Introduction

Blackjack belongs to the sunflower family, Asteraceae in the genus, Bidens which comprises around 200 species of annual or perennial herbs. Blackjack (black jack) in the African region may refer to any of the four or more species of related plants that are used as vegetable in various parts of the continent and especially Southern Africa: Bidens pilosa, Bidens bipinnata, Bidens biternata and Bidens schimperi. Young plants of blackjack may be confused with Galinsoga parviflora (Gallant soldier (English) but the leaves are a good distinguishing feature. The leaves of Galinsoga parviflora have a short stalk, and not divided into 3 leaflets. It is native of South America, but naturalized in tropical, subtropical and temperate parts of the world. It is also occasionally used as a leaf vegetable.

General information (Species account and ecological information)

In B. pilosa, the leaves are divided into 3 leaflets and the conspicuous peripheral petals are white. Bidens bipinnata (yellow-flowered blackjack) is similar to Bidens pilosa except that the former has yellow petals and more narrow leaflets that are divided (lobed). B. bipinnata is a cosmopolitan weed originating in Europe and Asia. B. biternata can be distinguished by the leaves, which are usually divided into 5-7 leaflets. The flowers are yellow. B. biternata is less frequently encountered and is believed to of African origin. B. schimperi has ribbed stems that are often purplish. The leaves are deeply divided into leaflets that are further divided into deep thin lobes and these may be lobed again. The peripheral flower petals are yellow. It is considered native with a distribution from Ethiopia to South Africa.
Bidens pilosa, is the more common of the four. This species is a highly adaptable and widespread, being found especially in tropical and warm temperate regions worldwide. In Africa, it is particularly prevalent and has a cosmopolitan distribution. The plant is known to thrive in various habitats, including disturbed areas, agricultural fields, grasslands, and along roadsides. In Africa, it is considered a widespread weed and an invasive species in many countries. Its reputation as a weed stem from its ability to outcompete native vegetation and reduce biodiversity in affected areas. Moreover, Bidens pilosa serves as a reservoir for plant viruses that can infect crops, posing a threat to agricultural productivity.
Despite being categorized as a weed, blackjack has been regarded as an edible plant by the Food and Agriculture Organization of the United Nations since 1975, and has been traditionally used as a food and medicine in America, Africa, and Asia. In Africa, the plant's fresh or dried tender shoots and young leaves are collected from the wild and utilized as a leaf vegetable, particularly during times of food scarcity. It is commonly consumed as a potherb, with its culinary use reported in countries such as Sierra Leone, Liberia, Côte d'Ivoire, Benin, Nigeria, Cameroon, DR Congo, Kenya, Uganda, Tanzania, Malawi, Botswana, Zambia, Zimbabwe, and Mozambique. The plant exhibits culinary diversity in its preparation and consumption and provide valuable nutrients such as vitamins A and C, iron, and calcium.
In addition to its role as a food source, Bidens pilosa holds a prominent position in African traditional medicine. For centuries, various communities and tribes have utilized different parts of the plant, such as roots, leaves, and seeds, to treat a wide range of ailments. Its medicinal properties are reported to include antibacterial, anti-inflammatory, antimicrobial, antimalarial, diuretic, hepato-protective, and hypotensive activities. Across Africa, different regions have their own traditional uses for Bidens pilosa. Examples include using crushed leaf sap to promote blood clotting, employing leaf decoctions to alleviate headaches, utilizing leaf powder decoctions to address kidney problems, and preparing herbal teas from the plant to reduce flatulence. The plant's extracts are even used to combat malaria in certain areas of southern Africa (Mvere, 2004, Kuo et al, 2021, Sarker et al, 2018, CABI, Xuan & Khanh, 2016).

Species accounts

Bidens pilosa - is a perennial plant that grows up to 0.5 m high and can reach up to 1.5 m in favorable environments. Stem: slender, stiff, and four-angled stems with spreading branches. Stout roots are similar to bulbous roots and spread by underground rhizomes. Leaves: arranged oppositely and feature petioles that extend noticeably beyond the leaf margin. Flowers: Flower-heads are 7-8 mm across with yellow central (tubular) florets. Some plants have flower-heads with white or cream 'petals. Fruits: capsules are about 5 mm long and flat-topped into a beaked shape with three to four valves. Seeds: Black, slender (1-1.5 cm long), ribbed, dry, one-seeded, 2–4 yellowish barbed bristles or awns at terminal end. 

Black jack has a high reproductive potential, with a single plant producing up to 6000 seeds per year. Seeds are also widely dispersed through the fruits hook-like bristles that embed themselves in clothing and the fur of mammals and feathers of birds. They are also spread by wind, water and soil and may remain viable for 5-6 years. The plant thrives in diverse habitats and soil types, benefiting from disturbances like fire and tillage. It forms dense stands that outcompete crops and native vegetation. Its allelopathic properties inhibit the growth of native plant seedlings. Additionally, it poses nuisances for transportation and recreation areas. Bidens pilosa is listed as a troublesome agricultural weed impacting at least 31 crops in over 40 countries. It is considered one of the most noxious annual weeds in East Africa. (Mvere, 2004, CABI, Bartolome et al., 2013).

Related species 
a.    Bidens bipinnata L. commonly known as Spanish needle is a widely distributed weedy species in North and South America, Europe and Asia. It is introduced in Africa and known from Cape Verde, Guinea, Sierra Leone, Côte d’Ivoire, Ghana, Togo, Nigeria, Cameroon, Malawi, Zimbabwe, Madagascar and South Africa. Bidens bipinnata can be distinguished from its close relatives, Bidens pilosa and Bidens biternata by its bipinnatisect leaves. The young leaves of Bidens bipinnata are sometimes consumed as a vegetable. In southern Africa, the young shoots are known for their spicy or tangy flavor and are consumed fresh or dried for storage. It is common for Bidens bipinnata to be mistaken for the more widespread black jack (Bidens pilosa) and is used as a substitute, often in mixtures. In Sierra Leone the leaves are squeezed over boils and are also eaten to cure them. Bidens bipinnata is widely used in South-East Asia as an emmenagogue, expectorant, stimulant, antidiarrhetic and antispasmodic. It is also used in the treatment of conjunctivitis, asthma, insect stings, wounds, earache and snakebites (Bosch, C.H., 2004).

b.    Bidens biternata, commonly known as the yellow flowered blackjack is a very widespread plant, growing wild in the temperate regions of eastern China, through to the subtropical and tropical regions of Africa, Asia and the Pacific. It is adventive in temperate regions of western Europe. It can be found in diverse habitats, including wetlands, marshes, fields, gardens, roadsides, thickets, teak forest and along the edges of lakes and rivers. This erect annual herb grows to a height of 1 meter. A distinguishing characteristic lies in its leaves, which commonly exhibit 5-7 foliolate patterns, with the basal pair occasionally exhibiting further divisions. The flowers of this herb manifest a vibrant yellow coloration and incorporate ray-florets. In the case of B. pilosa, the leaves are 3-foliolate, and if there are ray-florets, they will be white. The young leaves of the plant can be harvested and used as a leafy green vegetable. They are often cooked or added to salads, bringing a slightly bitter flavor to culinary preparations. The plant is also extensively used in traditional medicine against inflammation, infections, diabetes, malaria, leprosy, ulcers and diarrhea and digestive disorders (Tropical Plants Database, Zahara et al, 2015, Hyde et al, 2023).

Ecological information

Black jack grows freely in disturbed places, or as a weed in crops such as cereals, pulses and cotton, in sunny or slightly shaded places, from sea level up to 2400 m altitude. The optimum temperature for germination is 25–30°C. Temperatures below 15°C and above 45°C are not favorable. It thrives in soils with a pH ranging from 4–9 and can tolerate a very high salinity, up to 100 mM NaCl. Flooding reduces seed emergence (Mvere, 2004).
Agronomic aspects

Bidens pilosa can be propagated from seeds, cuttings or divisions making it relatively easy to multiply. The seeds of this plant exhibit non-dormancy and typically sprout within a short span of 3 to 4 days when placed in moist topsoil. The harvested fruits tend to cluster together, forming large, intertwined balls, which can pose a challenge for separation. However, after undergoing a drying and storage process lasting over three weeks, the barbed hooks on the fruits become more fragile and break off easily. The dry seeds themselves are resilient and can remain viable for at least three years. The emergence is good when seed is buried not more than 4 cm in the soil. The seed will not germinate if buried at more than 6 cm. Soaking of the seed in water increases germination. (Mvere, 2004).
Planting 

Black jack is a partially cultivated plant found in areas where selective weeding practices are implemented. Its cultivation is straightforward, involving broadcasting or row sowing of seeds, followed by thinning out the seedlings to a spacing of 10-15 cm. When grown for consumption as a vegetable, the plants reach harvest maturity within 4-6 weeks after emergence, prior to seed formation. Multiple plantings, typically 4 or 5 per year, may be carried out. If black jack is cultivated for its leaves, which are used as an antimalarial medicine, removing the flowers becomes necessary to delay senescence and promote continual growth (Mvere, 2004). Care must be taken while growing blackjack since it is a potential weed. Plants could be harvested early before seed formation.

Harvest and post-harvest practices

Harvesting

In cultivation, the initial harvest of B. pilosa typically takes place around 4-6 weeks after sowing, when the plants have reached a height of 15-30 cm. Harvesting methods include manual picking, cutting, or uprooting of the plants. If the plants are pruned or topped, a second harvest can be obtained approximately 2 weeks later. (Mvere, 2004).
Post-harvest practices
Tender leaves, shoots or whole young plants are washed and tied into bundles, after which they may be taken to the market. Although they are not as perishable as most leafy vegetables, the leaves intended for marketing are harvested late during the day or early in the morning so that they remain fresh for marketing. Leaves may also be parboiled and then dried in the sun for later use. Leaves, stems, roots and seed intended for medicinal purposes do not require any delicate handling (Mvere, 2004).
Market value 

As a vegetable and medicinal plant, blackjack is commonly found in limited quantities at local markets. It is obtained from young plants, leaves, and shoots collected from the wild or during field weeding. In southern African countries, it appears early in the rainy season when other fresh vegetables are scarce. Dried black jack leaves are significant during periods of food scarcity in the dry season. Nigeria, Benin, and Zimbabwe have reported small-scale cultivation, but there are no available statistics regarding the cultivated area or traded volumes. International trade of black jack has not been documented. (Mvere, 2004).

Nutritional value and recipes

Black Jack, is a nutrient-rich plant containing a range of essential nutrients like vitamins, minerals, and antioxidants. Black Jack is a good source of vitamin A, benefiting vision and skin health. The plant is abundant in minerals such as potassium, calcium, and magnesium. Potassium helps regulate blood pressure and maintain heart function, while calcium and magnesium are crucial for strong bones and teeth.
B. pilosa is known for containing over 40 bioactive compounds with various beneficial effects. While there has been significant research on the phytochemistry and biology of B. pilosa and its compounds, there is currently no comprehensive review available on its potential dietary role in managing metabolic syndrome (Kuo et al, 2018, CABI International, 2023)

Table 1 Nutritional value of 100 of Bidens pilosa leaves

	Black jack leaves stew, with groundnut flour, (Chisoso chotendela)	Recommended daily allowance (approx.) for adultsa
Proximate composition and dietary energy
Moisture (g)	80.1	2000-3000c
Energy (kCal)	109	2300
Energy (kJ)	457	9623
Protein (g)	5.9	50
Fat (g)	6.9	<30 (male), <20 (female)b
Carbohydrate available (g)	1.32	225 -325g
Fiber (g)	2.8	30d
Ash (g)	1.5
Mineral composition
Ca (mg)	582	800
Fe (mg)	9.3	14
Mg (mg)	203	300
P (mg)	76	800
K (mg)	317	4,700f
Na (mg)	111	<2300e
Zn (mg)	3.32
Cu (mg)	1.32	0.9
Mn (mcg)	7057
Se (mcg)	3.2	60
Bioactive compound composition
VitA-RAE (mcg)	7	800
VitA-RE (mcg)	270	800
Thiamin (mg)	0.14	1.4
Riboflavin (mg)	0.07	1.6
Niacin (mg)	1.6	18
Vit B6 (mg)	0.201	1.3
Folate (mcg)	91	400f
Vit B12 (mcg)	0	3
Vit C (mg)	7	60
Vit D (mcg)	0	5 – 15*
Vit E (mg)	2.11	9

Source (Nutrient data): ^hThe Malawi Food Composition Database (MAFOODS). https://dl.tufts.edu/downloads/g158bw806?filename=d217r336d.pdf

Draining the water several times leaches away water soluble nutrients significantly.

a Lewis, J. 2019. Codex nutrient reference values. Rome. FAO and WHO, b NHS (refers to saturated fat), c https://www.hsph.harvard.edu/nutritionsource/water/, d British Heart Foundation, e FDA, f NIH, g Mayo Clinic

Complimentary recipes
a.    Mutsine (Blackjack leaves)
Ingredients 
•    1 bunch tsine (blackjack leaves), chopped
•    1 large tomato, chopped
•    1 medium onion, chopped
•    250 ml boiling water
•    1/2 tsp salt
•    3 tbsp oil
Cooking procedure
•    Get your ingredients together. These include; 1 bunch tsine (blackjack leaves), chopped
•    1 large tomato, chopped
•    1 medium onion, chopped
•    250 ml boiling water
•    1/2 tsp salt
•    3 tbsp oil
•    Put boiling water in pot. Add the blackjack leaves. Boil for 5 min then drain the water, reserving just a tablespoon.
•    Put the blackjack leaves back into the pot. Add the tomatoes, onions, salt, oil and reserved water. Allow to simmer until the tomatoes and onions are cooked through.
•    Taste for seasoning and adjust accordingly. 
Source: (ZimboKitchen, 2019

Complimentary recipes
a.    Mutsine (Blackjack leaves)
Ingredients 
•    1 bunch tsine (blackjack leaves), chopped
•    1 large tomato, chopped
•    1 medium onion, chopped
•    250 ml boiling water
•    1/2 tsp salt
•    3 tbsp oil
Cooking procedure
•    Get your ingredients together. These include; 1 bunch tsine (blackjack leaves), chopped
•    1 large tomato, chopped
•    1 medium onion, chopped
•    250 ml boiling water
•    1/2 tsp salt
•    3 tbsp oil
•    Put boiling water in pot. Add the blackjack leaves. Boil for 5 min then drain the water, reserving just a tablespoon.
•    Put the blackjack leaves back into the pot. Add the tomatoes, onions, salt, oil and reserved water. Allow to simmer until the tomatoes and onions are cooked through.
•    Taste for seasoning and adjust accordingly. 
Source: (ZimboKitchen, 2019)

Introduction

Solanum macrocarpon is a species of flowering plant in the Solanaceae family, which is native to Africa. It belongs to the genus Solanum, which includes over 1,400-1,500 species of plants, including popular foods such as tomatoes, potatoes, and peppers. Within the Solanum genus, S. macrocarpon is part of the Leptostemonum clade, which includes other edible plants like S. aethiopicum, S. anguivi, and S. torvum.

Gboma eggplant is a highly variable plant species, with different varieties grown and consumed throughout Africa. The plant is a shrub that can grow up to 2 metres tall, and its leaves, young shoots, and fruits are the most commonly consumed parts. Gboma eggplant leaves, and young shoots are cooked and consumed as a vegetable. These leaves are used in a variety of dishes, including soups, stews, and sautés, and are known for their rich nutritional content. The taste is more or less bitter and very much liked. The leaves can either be steamed as practised in Uganda or fried in oil with onions. They are a good source of vitamins A and C, calcium, and iron, making them an essential dietary component for many people in Africa.
In addition to its use as a leafy vegetable, Gboma eggplant also produces fruit commonly consumed raw or cooked. The fruit is large and has a long storage life of up to three months, making it an important food source in areas with limited access to fresh produce. It can be stuffed or used as a pasta substitute, and is an essential ingredient in many traditional African dishes. In addition to its culinary uses, Gboma, has been used in traditional medicine for treating a variety of ailments such as skin infections, asthma, rheumatic diseases, constipation, diabetes, and weight reduction. Its uses vary across different African countries. In Sierra Leone, the boiled leaves are chewed to treat throat problems, while in Kenya, the crushed leaves are taken to treat stomach problems. The fruits are consumed in Nigeria as a laxative and to treat cardiac diseases. Additionally, the juice of the boiled fruit is consumed in Kenya to get rid of hookworms. Recent studies have suggested that Gboma eggplant may have anti-inflammatory and antioxidant properties, which makes it a promising candidate for further research. In Ghana and Nigeria, the fruits of the Gboma plant are considered symbols of blessings and fruitfulness and are often offered as tokens of goodwill during social events such as visits and marriages.
(Bukenya. & Bonsu, 2004, Specialty produce, 2021, Food from Africa., 2021).

General Information (Species account and Ecological conditions)

Species account

Gboma eggplant plant can grow up to 1.5 meters tall. It has smooth stems or stems with small hairs, and its leaves are simple and alternate. Leaves can grow up to 46cm long and 30cm wide and may have parts that stick out up to 8cm long. The flowers have five or six parts, and the female flowers are bigger than the male flowers. The fruit is round and can be green when it's young and yellow or brown when it's ripe. The fruits are of different shapes and colors depending on the choice of the farmer. The first leaves are narrow and almost without stems (Schippers, 2000).

The Gboma eggplant plant can be divided into two main groups: the leafy group and the fruity group. The leafy group is commonly found in West and Central Africa, while the fruity group is mainly found in the humid coastal areas of West Africa, with less frequency in East Africa. However, the distinction between the two groups is not strict, as the leaves of the fruit varieties are also consumed.
The leafy group can be recognized by its mature fruit, which can be yellow, brown, or orange-brown in color. These fruits are often cracked and filled with seeds, making them bitter and unsuitable for eating. The leaves of this group are relatively small, not divided into lobes, and usually don't have thorns.
On the other hand, the fruity group has larger fruit with a round shape and a smooth, uncracked surface. The calyx (the part at the base of the fruit) is soft and wide, and the fruit has fewer seeds. The large leaves of this group are edible when young and may have prickles, usually along the midrib or larger veins. Some leaves may also have hairs, especially along the veins and on the lower surface.  (Schippers, 2000).

Ecological information 
Optimal growth of Gboma eggplant is dependent on favourable climatic conditions, proper soil management, and efficient water management. Climatic conditions suitable for growing Gboma eggplant include a tropical sub-humid climate with a temperature range of between 20°C to 30°C. It requires well-drained soils with good organic matter content, a pH range of 5.5-6.5, and moderate soil fertility. 
Water management is critical for Gboma eggplant cultivation. Irrigation should be done at optimal intervals and depths to ensure the crop receives the required amount of water to support growth and development. Organic matter can be used to improve soil water retention capacity and reduce water loss through evaporation. Proper water management reduces the risk of waterlogging, which can negatively affect the growth and yield of Solanum macrocarpon.

Agronomic aspects

a. Seed sources
African eggplant seeds can be obtained from seed companies or directly from farmers. It is advisable for farmers to produce their own seeds to ensure self-sufficiency. When cultivating plants for seed production, it is best to isolate them from other solanaceous plants such as tomatoes and potatoes, preferably on soils that have not recently grown these crops. For optimal seed production, a wider seed spacing of 60 cm x 20 cm is recommended, resulting in a seed rate of 1.5 kg seed/ha (Kalb et al., 2002).. 

b.  Planting 
African eggplants are typically cultivated from seeds, which can be directly sown or started in a nursery. They can be grown alone or as intercrops with other food crops. To ensure optimal growth, it is important to properly prepare the land. This involves digging to loosen the soil and remove any hardpan. In drylands, terracing is recommended to retain rainwater within the farm. After digging, well-decomposed manure is incorporated into the soil to create a well-drained structure with fine particles.
The prepared land is then divided into beds, preferably one meter wide. In wet and humid areas, raised beds are suitable, while sunken beds work well in dry areas or seasons. Additionally, farmyard manure or compost is applied and thoroughly mixed. To sterilize the soil, prevent soil-borne diseases, and control weeds, a layer of grass or similar material can be burned on top of the bed. This also adds a nutrient-rich ash, especially potash, to the soil. (Kalb et al., 2002).

c. Nursery Bed management 
African eggplants thrive when initially grown in a nursery bed and later transplanted to the main garden. To create the nursery bed, select a location away from drainage channels or slopes, yet accessible to a water source. In humid areas, raise the nursery bed at least 20cm above the ground to prevent waterlogging, while in arid and semi-arid regions, make it sunken to reduce water loss. Loosen the soil and incorporate well-decomposed manure before sowing the seeds.
Seeds can be sown by broadcasting or in rows (row planting). Mix the seeds with fine soil at a ratio of about 1:10 (seed to soil). If broadcasting, combine the seeds with dried poultry manure, ash, fine soil, or sand at a ratio of 1:10 to 1:20. Create 2cm deep furrows spaced 15cm apart. Sow the seeds and lightly cover them with soil. Apply mulch and water through it, preferably in the evening. Within 10-14 days, the seeds will germinate. Remove the mulch from the seedlings and place it between the rows. Provide shade over the nursery using light materials that allow sunlight to reach the seedlings.
Transplant the seedlings after 1-1.5 months of germination. Space the plants 1m apart between rows and individual plants. Prior to transplanting, add two handfuls of well-decomposed manure per planting hole (Kalb et al., 2002).

d. Transplanting and spacing 
To ensure successful transplanting, use the water stress method to harden off the plants. Gradually reduce watering and expose the seedlings to outdoor conditions over 4-6 days before transplanting. Select strong and disease-free seedlings for transplantation. Late afternoon is the preferred time for transplanting. Transplant when the seedlings are around 8 to 15 cm tall with six true leaves, typically after four weeks.
Before transplanting, thoroughly water the soil. Dig holes 30 cm x 30 cm apart and add well-decomposed manure to the holes. Alternatively, an initial spacing of 20 cm within the row and 40 cm between rows can be used. Ensure the roots are covered with soil and gently pressed for good root-to-soil contact. Avoid damaging or breaking the roots during transplanting. A hand fork can be used to carefully remove seedlings from the nursery bed, and if needed, a basin with water can be used for transportation. Replace any missing plants to maintain an even crop (Kalb et al., 2002).

Direct sowing
Direct sowing either in irrigation systems or rain-fed results in taller plants and when there is adequate room, in more and larger leaves and branches and better dry-matter content when compared with transplanting. The seeds are planted by broadcast or in lines. If by broadcast, one should ensure even distribution. A seed rate of 1.5kg/ha is used (Kalb et al., 2002).

Row planting 
To use the furrow gardening method, start by making shallow furrows with a stick or finger, leaving about 30 cm between rows. Drop your seeds evenly as you move at a steady speed along the row. After sowing, the bed should be covered with a thin layer of soil to prevent ants from carrying away the seeds or birds from picking them. Typically, it takes 5-10 days for the seeds to germinate. Water your seeds using a watering can and avoid washing them out of the furrows. Once the plants have germinated, the bed can be mulched with tall grass or a similar material to retain moisture, which can be removed later. 
Thinning
After germination, the strongest plants are retained, and the others removed for transplanting or consumption. Thinning should be done with the type of nightshade and hence its growth habit and size in mind. Four weeks after planting, the crop is thinned (starting with taller ones) to leave a spacing of about 15 cm from one plant to the other during the dry season. Thinning can be continued on regular basis until the desired spacing is reached, which depends a lot on the species. During thinning, the whole plant is uprooted. Thinned plants should be brought to the marketplace with their roots attached and moistened to retain their fresh appearance.

Harvest and post-harvest practices

Harvesting

The Gboma leafy vegetable is typically harvested 6-9 weeks after transplanting, generally within a week of flowering. Periodic leaf collection continues throughout the year, depending on water availability. During the initial harvest, the entire shoot, including the terminal bud and sometimes the flowers, is picked. Subsequent harvests occur every two weeks and involve gathering side shoots. This method promotes ongoing growth, allowing for extended harvesting. For Gboma eggplant, unripe fruits should be harvested 2-4 months after planting for consumption, while ripe fruits should be collected a month later for seed extraction (Bukenya & Bonsu, 2004).

Post harvesting practices 
Proper post-harvest practices are important to ensure the longevity and quality of Gboma eggplant leaves and fruits. Freshly harvested leaves and fruits can be easily transported and kept in good condition for an extended period, particularly in shaded or cool areas. To maintain the freshness of the leaves, sprinkling them with water can be effective. This not only helps to keep the leaves hydrated but also slows down their respiration rate, which can ultimately extend their shelf life.
There are various methods available for preserving vegetables. One such way is through local refrigeration. This involves constructing a 1-meter-high brick structure with two separate walls, filled with sand or charcoal dust in between. The structure should be placed under a shade and an elevated water tank installed nearby. A small pipe should be used to keep the sand or charcoal dust moist, and racks placed inside to hold the vegetables.
Another method of preservation is through the use of a pot. After harvesting the vegetables, they can be stored in a pot placed under a shade. The pot should be surrounded by sand or charcoal dust, which should be kept moist by regularly adding water. It is important not to pour water into the pot.
A third method is through the use of a solar dryer. This involves drying the vegetables using solar dryers and then packaging them for future use during the dry season. Although vegetables can be dried traditionally under the sun, using solar dryers is a more efficient method as it helps to retain more nutrients (Bukenya & Bonsu, 2004).

Value addition, value chain and markets 

Solanum macrocarpon is a widely consumed vegetable in Africa, commonly found in local markets. It is highly nutritious and valued as a food source for both humans and animals. While statistics on its production and trade are not available, some Gboma fruits are exported from countries like Senegal and Uganda to European markets such as Paris and Brussels. Similarly, Santo Domingo and Suriname export gboma fruits to the United States and Europe, including Amsterdam.
(Bukenya R. & Bonsu, K.O., 2004)

Nutritional value and recipes 

Solanum macrocarpon leaves offer a range of significant nutrients and associated benefits. They contain a moderate amount of protein, supporting muscle growth, repair, and cellular functions. The high fiber content promotes digestion, regular bowel movements, and can aid in weight management while supporting heart health. These leaves are also a notable source of calcium, contributing to the development and maintenance of healthy bones, teeth, and facilitating muscle function and nerve transmission. The leaves have a significant amount of iron, necessary for red blood cell production, preventing iron-deficiency anaemia, and supporting oxygen transport throughout the body.
Being a good source of potassium, these leaves help maintain fluid balance, support nerve function, and assist in muscle contraction. 
Additionally, Solanum macrocarpon leaves contain vitamin A, vital for vision health, immune function, and maintaining healthy skin. Vitamin A also acts as an antioxidant, protecting cells from damage. Furthermore, the presence of vitamin C in these leaves contributes to a strong immune system, collagen synthesis, antioxidant activity, and aids in the absorption of iron from plant-based sources. They also contain various B-vitamins, including thiamine, riboflavin, vitamin B6, and folate, which play essential roles in energy metabolism, neurological function, and the synthesis of DNA and red blood cells.
Table 1: Approximate nutritional content of 100 g of African eggplant (Solanum macrocarpon) leaves

Proximate composition and dietary energy	African eggplant leaf	Recommended daily allowance (approx.) for adults
Energy (Kcal)	48	2300
Protein (g)	4.4	50
Fat (g)	0.8	<30 (male), <20 (female)b
Carb (g)	3.7	225 -325g
Fibre (g)	4.2	30d
Ash (g)	1.7
Mineral composition
Ca (mg)	332	800
Fe (mg)	4.3	14
Mg (mg)	81	300
P (mg)	44	800
K (mg)	443	4,700f
Na (mg)	26	<2300e
Zn (mg)	0.73	15
Bioactive compound composition
Vit A-RAE (mcg)	297	800
β-carotene equivalent (mcg)	3,560	600 – 1500g
Vit A RE (mg)	0.42	800
Thiamin (mg)	0.08	1.4
Riboflavin (mg)	0.17	1.6
Niacin (mg)	0.7	18
Vit B6 (mcg)	0.29	1.3
Folate (mcg)	69	400f
Vit C (mg)	69	60

Source: (Nutrient data): FAO/Government of Kenya. 2018. Catalogue of Selected Indigenous Vegetables in Ghana. (Oboh et al., 2005)
$ Draining the water several times leaches away water soluble nutrients significantly.
a Lewis, J. 2019. Codex nutrient reference values. Rome. FAO and WHO
b NHS (refers to saturated fat)
c https://www.hsph.harvard.edu/nutritionsource/water/
d British Heart Foundation
e FDA
f NIH
g Mayo Clinic

Complimentary Recipes
a.    African eggplant leaves with pumpkin kernels
Cameroon recipe. 
Ingredients 
• 3 bunches African eggplant leaves 
• 1 g limestone 
• 4 cups (800 g) of pumpkin kernels/seeds 
• 1 kg meat 
• Dried shrimps (optional) 
• 1/4 refined vegetable oil 
• 1 clove of garlic, 1 small piece of ginger, 2 large onions, 1 large leek, 1 stalk celery, two yellow peppers 
• 15 - 20 grains white pepper 
• Seasoning (stock cubes, salt, pepper) 

Preparation 
•    Sort, wash, and cut the African eggplant leaves into small pieces.
•    Dilute 1 g of limestone in a cup of hot water, filter to remove grit, and pour the liquid into a pot with 1.5 - 2 litres of water. Add the leaves and cook until soft, stirring occasionally.
•    Once the leaves are soft enough, remove them from the heat, strain, and rinse with cool water.
•    Squeeze out excess water and shape the leaves into balls.
•    Boil the meat and prepare onions, leeks, and celery by slicing them.
•    Peel ginger and garlic, clean peppers, and crush them together.
•    Chop shrimps and grind pumpkin kernels/seeds.

Cooking
•    Heat some vegetable oil in a pan and sauté onions until brown.
•    Add leeks and cook for 3-5 minutes.
•    Add celery and cook for a few more minutes.
•    Mix garlic, ginger, and peppers, along with boiled meat and half a glass of water. Simmer for 10 minutes.
•    Add vegetables, stir, and pour a glass of water. Cover the pot.
•    Once the vegetables start boiling, add pumpkin powder and simmer for 10 minutes without stirring.
•    Stir the pumpkin powder into the vegetables.
•    Heat two spoonfuls of vegetable oil in another frying pan. Quickly brown the chopped shrimps for 5-10 seconds and pour over the vegetables.
•    Immediately cover the pan to allow the vegetables to absorb the aroma.
•    Boil for a few minutes.
•    Season with a teaspoon of ground white pepper and adjust the seasoning to taste.

Serving: Serve with tubers of your choice.
Source: (Chagomoka et al, 2004)

b.    Ngogwe

Ingredients
•    120 g African eggplant
•    80 g okra fruits
•    100 g carrots
•    80 g onions
•    100 g tomatoes
•    2 eggs
•    ½ cup cooking oil
•    Salt to taste
•    1 cup water
Preparation
•    Wash, peel and chop the tomatoes
•    Clean and chop the onions
•    Wash, peel and cut lengthwise the carrots
•    Wash and trim the pedicles of African eggplants
•    Wash and trim the end tips of the okra
•    Fry the onions lightly, add tomatoes, salt and stir until soft
•    Add okra, African eggplant, carrots and stir well
•    Whisk the eggs with 1 cup of water and add while stirring slowly for 5 minutes
•    Season to taste and serve while hot as a relish

Source: Traditional recipes. (AVRDC & IPGRI., 2006)

c.    African eggplant sauce 
(Kamga & Mecozzi, n.d.)
Ingredients 
• 1 kg African eggplant 
• 1 kg chopped meat or crumbled smoked fish
 • 2 large onions 
• 1/4-liter refined vegetable oil 
• 2 large tomatoes 
• 3 tablespoons mayonnaise 
• 1 clove garlic, 1 stalk celery, 1 large leek, two yellow peppers
 • Seasoning (stock cubes, salt, pepper

Preparation 
•    Wash the African eggplant, 
•    Soak for few minutes in hot water and remove the skin. 
•    Cut each fruit into four pieces. 
•    Crush together garlic, celery, leeks, peppers and tomatoes. Finely slice onions.
Cooking
•    Place a pan on the fire, add the vegetable oil, and heat. 
•    Brown the sliced onions in the oil. 
•    Add the crushed garlic, celery, leeks, peppers and tomatoes and simmer. After 3-5 minutes, add the meat or fish, and cook until done. Add African eggplant fruit and cook for about 30 minutes to reduce the amount of water. 
•    Add mayonnaise, salt and simmer to obtain the consistency you prefer. Adjust the seasoning as needed. 
•    Serve with rice or tubers of your choice.

Introduction

Gnetum africanum, commonly known as African joint fir or eru, is a plant species that belongs to the family Gnetaceae and the genus Gnetum. It is one of the several species within the genus Gnetum. The genus comprises approximately 35 species of small trees, shrubs, or most often lianas, found in tropical South and Central America (about 7 species), Africa (2 species), and Asia (about 25 species). They look much like dicotyledonous flowering plants (having opposite leaves with a net venation and cherry-like seeds), although they are gymnosperms. The 2 African species G. africanum and G. buchholzianum, are very similar and have been classified in section Gnetum. They are found in humid tropical forests ranging from Nigeria to Cameroon, the Central African Republic, Gabon, the Democratic Republic of the Congo, and Angola. The two species are quite similar and can only be distinguished by the shape of the leaf and the characteristics of the reproductive structures. In its cultivation zones, Gnetum leaves form a very popular and highly valued vegetable; they are often picked from the wild and sold at local markets, where they are frequently a significant commodity. The plant is highly regarded for its nutritional value, as it is rich in essential nutrients such as vitamins, minerals, and proteins. The leaves of Gnetum africanum are commonly used in traditional African dishes, including soups, stews, and sauces. The plant is highly regarded for its nutritional value, as it is rich in essential nutrients such as vitamins, minerals, and proteins.
In addition to its culinary applications, Gnetum africanum also possesses medicinal properties. It has been traditionally used in African herbal medicine for various purposes, In Nigeria, eru is used for treatment of piles and high blood pressure and also as medicine against enlarged spleen, sore throat and as a purgative. In the Central African Republic, the leaves are eaten to treat nausea and as an antidote to arrow poison made from Periploca nigrescens Afzel. In Cameroon the leaves are chewed to mitigate the effects of drunkenness and they are taken as an enema against constipation and to ease childbirth. They are also used to treat boils and fungal infections on the fingers. The supple stem is sometimes used as rope. Gnetum africanum often commands lower market prices than G. Buchholzianum because of its thinner and paler leaves. Additionally, the leaves are exported to ethnic marketplaces throughout the world. Current harvesting methods are unsustainable, so research is being conducted on economically producing the plant. (Schippers & Besong,, 2004, Mialoundama, 1993).

Species accounts

Both African Gnetum species (Gnetum africanum and Gnetum buchholzianum are dioecious (with plants being either male or female) lianas with two different types of stems. The orthotropic (vertical) ones have small, scale-like leaves and rapidly grow vertically, reaching main branches of a tree where they produce stems with fully developed leaves. The stem continues climbing until it reaches the canopy where it branches into several leafy stems. Female plants often show more vigorous growth with stronger stems than male plants. Eru continues to grow during the dry season and new shoots may develop where the stem has been cut or where side shoots have been removed. Under wild conditions, both species grow and form underground tubers or roots that store plant food reserves. These can remain alive for many years when the vegetation and the Gnetum vines above ground are cleared and the soil surface is laid bare. The distinctly coloured drupe-like seeds are probably dispersed by birds and other animals.

G. africanum leaves are relatively thin, light to pale green, and ovate to oblong in shape. The male catkins are of equal width from the base to their tip. G. buchholzianum leaves are elliptic to oblong in shape, thick and dark green. It produces catkins with a diameter decreasing from the base to the top internode (Schippers, 2004). The dry matter content of fresh Eru leaves is much higher than for other dark or medium green leafy vegetables. This gives a feeling of firmness during preparation, leading some customers to view eru as a meat replacement. Gnetum africanum is threatened with disappearance because of intensive gathering and cultural activities which are destroying the forests that support the plants. Possible adoption into farm systems is a step on the right way to conserving this plant (Orwa et al., 2009, Schippers, 2004).
Ecological requirements
Eru can be found in the rain forest from sea level up to about 1200 m altitude and prefers an annual rainfall of about 3000mm. 
Gnetum africanum and Gnetum buchholzianum thrive in a wide range of habitats, including farm fallows or abandoned farmland, secondary forests, and closed forest. The vines of both Gnetum species climb supporting big and small trees, dead trees, saplings, shrubs, other climbing vines such as rattan palms, and a host of other plant materials in the complex tropical humid forest, where they grow luxuriantly and produce significant quantities of leaf biomass. It is usually found on middle and under-storey trees together with other climbers and frequently forms thickets. It can also be found in riverine forest areas that are otherwise too dry for the species. Gnetum africanum is mainly found at the periphery of primary and secondary forests. Gnetum buchholzianum is primarily found in the forest, especially near openings created by fallen trees (Asaha, 2000, Mialoundama 1993, Shiembo, 1996, Shiembo, 1999, Schippers, 2000).
Agronomic aspects 
Seed germination is slow and irregular; germination periods of 1 year or more are pretty normal. Even so, the germination percentage is very low in a nursery. It is assumed that seeds need pretreatment, such as passing through the intestines of a bird, fruit bat, squirrel, or other animals, before they germinate. Seed is typically found only in the tree canopy. Seed collection is thus far from easy, a reason why eru is hardly cultivated.
The cheapest propagation method available is rooted cutting. Fresh stem cutting is taken, for which a stem with a single pair of leaves is adequate. These cuttings are placed in well-decomposed sawdust as a rooting medium, and care is taken to keep the leaves moist. A mist system is ideal for this purpose, although not essential, and other means of keeping the leaves wet with a fine spray if water can also be used.
Evapotranspiration of the new cuttings should be minimized and it is recommended that the plant bed be covered with fine gauze, nylon net, or a loosely woven piece of cloth. Once rooting has taken place, which may take about a month, the new plantlets should be transferred to a proper growing medium with forest soil. Polythene sleeves filled with soil can be used for this purpose. Once side shoots have developed from the nodes, plants should be given more space to create an adequate flow of air 
After about 6 weeks, the rooted cuttings are transferred to polythene sleeves, bamboo pots, or other containers, where they remain for a further 2-3 months. The soil mixture for these containers consists of 25% sand and some compost, supplemented with forest soil. Field planting occurs at the beginning of the rainy season, preferably next to a young tree or shrub.

Management
Eru is mainly collected from wild stands; farmers often retain it when clearing fields. If cultivated, farmers need to provide support, e.g., by using commercial plantations of rubber trees, oil palm, and other crops. The use of fences was only found to be successful when there is enough shade, and it is generally too expensive. Fully exposed plants do not grow well; their leaves are thin and pale green. In experiments, nutrients, especially nitrogen, have shown a positive effect on growth and rate of leaf development.

Harvest, post-harvest practices

The current method of harvesting, especially for export trade, is by either uprooting whole plants or pulling the stems from the trees. This leads to large-scale destruction of natural stands. Occasionally, trees have to be cut to reach leafy stems in the canopy. This is mainly done during the dry season when the forest is more accessible and where there is little work on the farm. Controlled harvesting in which only side shoots or parts of stems are collected is clearly better than destructive harvesting. After such harvesting, new shoots may develop where a stem has been cut or where side shoots have been removed. Preliminary observation indicates that 3-4 harvests per year are possible, whilst still allowing substantial regrowth. More frequent harvesting will result in thin leaves that are considered inferior. 
The first harvest may take place 6-9 months after planting and the total lifespan of eru is estimated at over 10 years.

Post-harvest practices
Leaflet stems of eru remain fresh for at least a week. Branches collected from the forest are brought to collecting points from where they are sold in the local markets or exported. For this trade, whole leafy stems are packed in large bales. Selection takes place on the size and texture of the leaves, which is mainly dependent on the species. Gnetum buchholzianum is more popular with consumers and expensive because its leaves are generally thicker than those of Gnetum africanum. The fresh leaves are somewhat leathery and are thus tough to eat whole. The leaves are therefore shredded into strips about 2 mm wide. This product can be prepared directly or dried for later use after reconstitution by soaking in water. This shredding process is done by placing several leaves on top of each other and cutting them with a sharp knife. It is a tedious job that is often done before export, mainly to black communities of Nigerian and Cameroonian origin in the U.S. and the U.K. (Schippers and Feeday, 1998).
Gnetum is often eaten as part of a mixture in a groundnut-based stew. It often replaces meat because of its high protein content and is thus much appreciated. To soften the otherwise tough product, people mix Eru with waterleaf, Talinum fruticosum, and these two vegetables are always eaten together.

Value addition, and market value 
Preservation of Gnetum
Chopped well-dried leaves are packaged in containers e.g. in polythene bags and stored in room temperature. They may keep well for about 1 year. The stored leaves are soaked in hot water prior to cooking.
In trade, consignments of Gnetum africanum and Gnetum buchholzianum are often mixed. Traders will pay more for the thick dark green leaves of the latter, but much variation is also caused by growing conditions. Most eru is consumed locally, but intensive trade has developed from Cameroon and more recently also from Gabon and the Central African Republic to meet the large demand in Nigeria. Most eru from Cameroon, Gabon and the Central African Republic is transported to Idenau, a coastal village in Cameroon, and from there by boat to Nigeria. Estimates for the annual export of eru leaves (both species) to Nigeria range between 2500 t and 4000 t. Another major marketing centre is the Koilo Region in Congo. Other marketing centres in Cameroon are Campo near Kribi for export to Gabon and the Mfoundi market in Yaoundé. Dried shredded leaves are exported, mainly from Nigeria to the United States and to a lesser extent from other countries to France and the United Kingdom (Schippers, R.R. & Besong, M.T., 2004).

Nutritional value and complimentary recipes 

Gnetum africanum is rich in fiber (28–37%) and protein (13–18%). The plant is high in carbohydrates -38–44% dry matter. Other values based on 100 g dry weight of leaves indicate: carbohydrates 70 g, of which 40 g is cellulose, protein 16.5 g, lipids 6 g and ash 7 g. The caloric value for G. africanum leaves therefore is much higher than in most vegetables, 248 to 307 kcal/100 g (Ali et al. 2011). The high protein and fat content of eru leaves explain why it is often used as a substitute for meat. The protein of Eru has all eight essential amino acids (isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine). This nutrient composition of Gnetum varies depending on the variety. The nutritional value of Gnetum buchholzianum is often higher than that of Gnetum africanum.

Proximate composition and level of nutrients in Gnetum leaves prepared in different ways

Proximate composition and dietary energy	Leaves (note superscript)	Recommended daily allowance (approx.) for adultsa
Water	37.391, 12-133	2000-3000c (g)
Protein	10.181, 13–183	50 (g)
Fat	14.21, 2–103	<30 (male), <20  (female)b (g)
Carbohydrates	38-443	225 -325g (g)
Fibre	28–373 g	30d  (g)
Ash	4.721, 2-33	(g)
Mineral composition
Ca	28.352, 130-2494	800 (mg)
Fe	5.232, 76-1214	14 (mg)
Mg	14.752, 39-894	300 (mg)
P	300 mg in 100 g of dry matter.	800 (mg)
K	1262, 0.08 mg/100 g of dry matter	4,700f (mg)
Na	262	<2300e (mg)
Zn	0.492, 0.8-1.34	15 (mg)
Se		60 (mcg)
Cu	0.062
Bioactive compound composition
Vit A-RAE		800 (mcg)
Vit A RE		800 (mcg)
β-carotene equivalent	400 mcg/100 mL	9600 (mcg)
Thiamin		1.4 (mg)
Riboflavin		1.6 (mg)
Niacin		18 (mg)
Vit B12		(mcg)
Folate		400f (mcg)
Vit C	1134 mg	60 (mg)

1Data in %. Source: AVRDC & IPGRI, 2006
2 Data in ppm. Source AVRDC & IPGRI, 2006. To convert to %, divide by 10000.
3Chemical composition of G. africanum (% of dry matter), Ali et al. 2011 (Ali, Fadi & Assanta, Mafu & Robert, Carole. (2011). Gnetum africanum: A Wild Food Plant from the African Forest with Many Nutritional and Medicinal Properties. Journal of medicinal food. 14. 1289-97. 10.1089/jmf.2010.0327.)
 4Chemical composition of G. africanum in %. Source: Ali et al. 2011.
RE=retinol equivalents. 
RAE =Retinol activity equivalents. A RAE is defined as 1μg all-trans-retinol, 12μg beta-carotene, or 24μg α-carotene or β-cryptoxanthin.
a Lewis, J. 2019. Codex nutrient reference values. Rome. FAO and WHO
b NHS (refers to saturated fat)
c https://www.hsph.harvard.edu/nutritionsource/water/
d British Heart Foundation
e FDA
f NIH
g Mayo Clinic

Complimentary recipes

1. Fumbwa (Kikongo, Lingala)
(DRC recipe of Gnetum)
Ingredients
1 teaspoonful salt
1 green pepper
4 tablespoonfuls of palm oil
8 tomatoes 
1 magii cube (seasoning)
10 teaspoonfuls peanut butter
2 onions, medium size 
300 g smoked fish
4 cups water

Preparation
Wash leaves and cut them into small pieces
Bring water to boil and then soak the leaves
Wash the leaves 3 times in the hot water
Heat palm oil and add all ingredients at once i.e. tomatoes, peanut butter, flavoring cube and smoked fish
Mix all the ingredients, add salt to taste and then add water
Cook in low fire till the vegetable is soft. This may take up to 2 hours
Serve with manioc or maize fufu. One may also eat with chikwangue

Remarks 
The Bakongo people of west DRC like this vegetable. They have however influenced other communities living in the capital, Kinshasa. Note also that, this preparation requires a lot of peanut butter and cooking because it is coarse.

2. Gnetum africanum with palm oil and peanut. 
Ingredients
•    500 g (or more) of Gnetum africanum, or substitute any other greens: Cassava leaves, collards, kale, turnip greens or similar; or spinach; cleaned, stems removed; and shredded, finely cut, or pounded in a mortar with a pestle 
•    one cup peanuts (or peanut butter) 
•    one or two ripe tomatoes, peeled and chopped (or canned tomato paste, or canned tomato) 
•    one leek (or one onion), finely chopped 
•    one piece of dried, salted, or smoked fish (the size of your hand), bones and skin removed, cleaned, soaked in water, and rinsed 
•    one cup red palm oil

Preparation procedure
•    Place the greens in a large pot. Add enough water to partially cover. Bring to a boil. Reduce heat, (do not cover), and simmer until greens begin to become tender. (Cooking time varies considerably depending on type of greens used.) Add water if pot becomes dry.
•    Grind, chop, or pound peanuts into a fine paste. (Or you can start with natural, sugar-free peanut butter.)
•    When greens are mostly tender and liquid is reduced, add tomatoes (or tomato paste), leek (or onion), and dried fish. Continue to simmer, on low heat, stirring occasionally. Simmer until everything is tender and ready to eat. 
•    Remove a cup of the pot liquid and combine it with the peanut paste in a bowl. Stir to obtain a smooth sauce. Stir the peanut sauce into the greens, and reduce heat to as low as possible. Top with red palm oil and simmer for a few more minutes. 
•    Serve with boiled yams or sweet potatoes and/or cassava tuber, banana leaf or rice. 
Source: http://www.congocookbook.com/c0219.html

Genetic resources
Eru is hardly cultivated at all at present. There is still massive exploitation of the remaining natural stands, which have almost disappeared in Nigeria and are becoming scarce in Cameroon, Gabon, and the Central African Republic. There is an urgent need to collect and preserve the diversity found within the two African Gnetum species, preferably throughout their natural range (AVRDC & IPGRI, 2006.) 

Prospects
Alternatives to destructive harvesting of eru should be found. Once the new methods of propagation and cultivation have been adopted, there will be scope for the development of eru as a new crop, for which there is already high demand and an attractive price could be paid. The diversity found between accessions is considerable, offering scope for improving quality and productivity (AVRDC & IPGRI, 2006).
 

General Information and Agronomic Aspects of Crotalaria 

Introduction

Crotalaria ochroleuca is a plant species belonging to the Crotalaria genus in family Fabaceae. The genus includes around 600 species mostly found in the tropical and subtropical regions, with Africa having the highest number of species at approximately 400. These plants can be found in various habitats, such as damp grasslands, floodplains, and along the edges of rivers and swamps. Crotalaria juncea, commonly known as sun hemp, is the most well-known species of the genus due to its use as a fiber crop and green manure. Apart from the cultivated C. brevidens, C. ochroleuca, and C. natalitia, some wild Crotalaria species, such as C. anthyllopsis Welw. ex Baker and C. Florida Welw. ex Baker, are occasionally collected as potherbs. C. ochroleuca and C. brevidens are two closely related African species used as vegetables. However, it can be difficult to distinguish between them as some information cannot be attributed to a specific species with certainty. C. ochroleuca can be identified by its pale-yellow flowers and fat pods, whereas C. brevidens has bright yellow flowers and a narrow diameter. Additionally, C. ochroleuca has a mild flavor, while C. brevidens is bitter. Despite their similarities, both species are commonly referred to as rattle pod, rattlebox, sun hemp, or slender leaf.

Crotalaria ochroleuca is a versatile plant species that has been used in various ways across Africa. In countries like Tanzania, Kenya and Uganda, the young leaves and shoots of the plant are cooked and consumed as a vegetable, similar to spinach. Apart from its culinary uses, the plant has also been traditionally used in medicine to treat various ailments like diarrhea, wounds, coughs, and rheumatism. This is due to the presence of alkaloids, flavonoids, and saponins that have potent medicinal properties. Furthermore, the plant has the ability to fix nitrogen in the soil, making it a valuable crop as a green manure and cover crop in areas with poor soil fertility. Its aesthetic appeal has also made it a popular ornamental plant in gardens and parks. The plant has recently been used as an agent to promote the germination of Striga, the parasitic plant that is a significant concern for maize and millet growers in Africa, and subsequently dies due to the lack of a suitable host plant. C. ochroleuca is also known to suppress Meloidogyne root-knot nematode populations and is locally used by East African farmers either in crop rotations or as a companion crop with nematode-susceptible vegetables such as tomatoes Additionally, oil extracted from its seed is sometimes used as an insect repellant.

(Abukutsa-Onyango, M.O., 2004, Sheahan, C.M. 2012, Schippers, R.R., 2004

Species account

Crotalaria ochroleuca is a tall, erect herb that can be either an annual or a short-lived perennial plant. It typically grows to a height of 0.5-1.5 m and has leaves divided into three narrow leaflets that are usually smaller than 13 cm long by 3 cm wide. The plant's stems have ascending branches and are ribbed. The flowers are yellow and have a noticeable purple vein. The plant produces fat pods that are shortly stalked and have blunt ends. These pods can grow up to 7 cm long by 2 cm wide and are slightly longitudinally compressed on one side. C. ochroleuca is mainly cultivated for its vegetables in tropical Africa, specifically from West Africa to the Sudan and south to Angola, Mozambique, Zimbabwe, and Botswana. The plant is distinguished from the Crotalaria brevidens species by its pod size and mild taste.

Related species

Crotalaria brevidens is a drought-tolerant species that grows up to 1.2 m tall. It has bluish-green leaves divided into three narrow leaflets, bright yellow flowers with conspicuous reddish-purple veins, and long, thin black pods. Native of tropical Africa from Nigeria to Ethiopia and south to Tanzania, it has been introduced in trials for use as a green manure crop. Its roots nodulate profusely, making it useful as green manure to improve soil structure and add nitrogen through the activity of Rhizobium bacteria. Native of tropical Africa from Nigeria to Ethiopia and south to Tanzania, introduced in trials for use as a green manure crop elsewhere. Its bitter taste is appreciated by older adults and it is usually cooked with Corchorus or milk to mask the bitterness.
(Maundu et al., 1999, Schippers 2002, Abukutsa-Onyango, 2007).

Characteristic	C. ochroleuca	C. brevidens
Leaf color	Bright-green	Bluish-green
Leaf length x width in mm	55x20	70x15
Standard of the flower	Pale-yellow/creamish	Bright-yellow
Pod length + diameter in mm	40-5- x15-20	50-70 x 7-10 (12)
Seed color	Light yellow	Light brown
No. of seeds/pod	60-70(-100)	(80-) 100-120
No. seeds/g	180g	210g

 

 

 

 

 

 

 

 

 

Adapted from AVRDC & IPGRI, 2006

 

2. Crotalaria juncea; is generally considered native to Bangladesh, Bhutan, and India, India but is now widely cultivated in the drier areas of the tropics and subtropics and many temperate regions as a green manure crop, often in rotation or as an intercrop with rice, maize, sorghum, tobacco, cotton, sugarcane, pineapple, coffee, and in orchards. The plant is also used to suppress weeds, prevent soil erosion, and reduce nematode numbers. It is a good indicator plant for potassium and calcium deficiencies. The dried stalks and hay are used as forage, while the woody stems remaining after fibre removal are used as fuel. Seeds are used to produce an adhesive for plywood and as a coffee substitute. They are also used medicinally to purify the blood, to cure impetigo and psoriasis and as an emmenagogue. However, it should be noted that the plant has been reported to be poisonous to livestock, and caution should be taken when feeding it to animals (Maroyi, 2011).

Climatic conditions, soil and water management

Ecological information

Crotalaria ochroleuca is a warm-weather plant that does well in temperatures between 20 – 30 °C for germination and 25 – 35 °C for growth. It adapts to a wide range of soil conditions, but it does not tolerate cool temperatures. The plant thrives in areas with high rainfall (above 600 mm/year) and altitudes of 500-2000 meters. It does best when cultivated under organic conditions due to its ability to fix nitrogen in the soil.

Propagation and planting

Planting

Crotalaria seeds are small in size and require thorough land preparation and a well-prepared bed for good growth. It is recommended to prepare 20 cm high beds during the dry season and 30 cm high beds during the wet season. Land should be prepared to a fine tilth for easy germination. Well-decomposed cattle manure is applied at the rate of about 1-2 kg/m if broadcasting or if sowing in rows, about 0.5 kg/m along the row. If using chicken manure, ¼ - ½ the rate of cattle manure is used.

Seeds are usually sown broadcast or in rows 30cm apart at a seed rate of 4-5 kg/ha. The seed germination capacity is usually good and it germinates in 3-4 days. Thinning is done 6-8 weeks after sowing to a spacing of 10-20 cm x 10-20 cm, depending on both soil fertility and moisture level. Under dry conditions, the spacing may be up to 30 cm x 30 cm. The thinned material can be used as the first harvest. When grown for a single harvest, 4-5 crops per year can be grown, but most farmers prefer to rotate rattlepod with other crops.

Currently there is no selection made to obtain the optimum variety and crops observed represent a mixture of landraces. However, there are clear differences in plant size and architecture, the branching capacity, the shape and the size of the leaves and several other characteristics that may well warrant basic breeding efforts. It is mainly self-pollinating so that a good level of varietal purity could be obtained within a few generations.

Companion crops

Crotalaria is a versatile crop that can be grown as a monocrop or intercropped with other crops that benefit from nitrogen fixation and nematode suppression. The roots of Crotalaria host numerous nodules that convert atmospheric nitrogen into ammonia, which boosts soil fertility for subsequent crops. As a mulch crop, it is sown in rows between the main crops such as bananas, sweet potatoes, kenaf, maize, or coffee. It is an ideal plant for crop rotation because its soil fertility effect lasts up to a year. Crotalaria is commonly used for subsistence farming and sometimes for market gardening. It thrives in semi-arid regions due to its deep taproots and lateral roots that tap into lower soil moisture levels. Broadcasting seeds is the preferred method for growing it as a fallow crop or green manure.

Husbandry

To ensure proper growth of Crotalaria Ochroleuca, it is recommended to thin the seedlings to a spacing of 15cm within the rows after one month of sowing. The excess plants can be consumed or sold. Weed control is essential, and hand weeding is the preferred method to maintain nutrient efficiency and good sanitation for healthy crops. Additionally, hand weeding will help control the parasitic weed Cuscuta suaveolens, which feeds on the roots of this crop and can hinder healthy growth if not kept under control. For optimal growth of slender leaf (Crotalaria brevidens), it is more effective to use farmyard manure instead of artificial fertilizers. Applying 20 tons of cattle manure per hectare is recommended. Inadequate rainfall can be supplemented with irrigation, especially in the early stages. Despite its ability to fix nitrogen, Rattlepod (Crotalaria ochroleuca) responds well to manure and biofertilizers.

Harvest, post-harvest practices and markets

1. Harvest

The first harvest of Crotalaria ochroleuca occurs about 4-6 weeks after sowing. At this time, the seedlings are thinned to 15cm within the rows. These thinned plants are used for the first harvest, and farmers can use ratoon systems from there to maintain desired spacing. To induce side shoots, the main stem is picked 15cm above the ground. Side shoots can then be harvested at 2-week intervals, with nitrogen fertilizer applied as topdressing to enhance their growth. This system has the advantage that some shoots can always be harvested, making it the preferred method for subsistence farming. The crop can continue to be harvested for over six months, and some farmers have been known to harvest a crop for a full year. As long as plants are cut for their shoots, no flowers, and therefore no seed, will be formed. Most farmers stop harvesting with the onset of the dry season, allowing the plant to flower and produce seed. Alternatively, farmers can harvest Crotalaria by uprooting it just before flowering when the stems are about 40cm tall and 8 weeks old. This method is commonly used when growing the crop as a catch crop between other crops. For mulching, the plants are uprooted or cut at soil level and placed between the crop rows.

(AVRDC & IPGRI, 2006, Grubben et al., 2004).

2. Post-Harvest

Fresh products are highly perishable, which is why they are so expensive in cities far away from the production areas. The leaves are picked up early or late in the afternoon, depending on when the product is delivered to the market. Once picked, roots should be washed in the case of uprooted plants. The shoots are tied in bundles and regularly sprinkled with water to reduce deterioration. Once tied up into bundles, the product should be put on a wire mesh if having to stay overnight. The product should not be stacked on one another as the leaves would be easily damaged. At 20-30ºC, they will last for 1 day; for longer storage, they should be kept below 20ºC. The leaves are often dried to be sold during the dry season. Drying in the sun takes 3-4 days during the dry season and 6-7 days during the rainy season. The flowers of Sunhemp can be dried under a shade for later use. These dried flowers retain their special flavour and are highly valued for use in soups (AVRDC & IPGRI, 2006).

3. Markets

Despite their nutritional benefits, the market value of crotalaria leafy vegetables in Africa is relatively low compared to other popular vegetable. Crotalaria is primarily grown in rural areas, where they are consumed locally or sold in local markets. Key factors contributing to its low market value include lack of consumer awareness about its nutritional benefits, misconceptions about its toxicity, and competition from other popular vegetables. To improve its status, consumers need to be educated about its nutritional benefits and new recipes and cooking methods need to be developed to make it more appealing. Additionally, more investment is needed in commercial production and distribution to increase availability in African markets

Nutritional value and recipes

Crotalaria leaves are a nutritious food source containing pro-vitamin A, calcium, iron, magnesium, protein, and fibre. They are particularly valuable in rural areas as they provide 100% of the daily requirement for some nutrients. Although bitter due to phytochemicals, they are an appealing dietary option. Furthermore, it is low in fat and calories, making it a healthy option for individuals who desire to maintain a balanced diet. Harvesting during the flowering stage optimizes nutrition value for some nutrients.

Table 1: Nutrient content of Crotalaria brevidens/100 g edible portion

Proximate composition	Nutrient content of /100 g edible portion	Recommended daily allowance (approx.) for adultsa
Proteins (g)	4.2 – 4.9	50
B-carotene (mcg)	2900 – 8700	600 – 1500g
Vitamin C (mg)	115 – 129	60
Calcium (mg)	270	800
Iron (mg)	4	14

Source: African Leafy vegetable market and Gardening practices by IPGRI & AVRDC 2006 (Unpublished)

a Lewis, J. 2019. Codex nutrient reference values. Rome. FAO and WHO

g Mayo Clinic

(Heuzé et al., 2017, AVRDC & IPGRI, 2006).

 

Complimentary recipes

The preparation of Crotalaria ochroleuca vegetable varies greatly across different African regions. There are various processing techniques for this vegetable, including boiling, mashing with maize, and cooking with cereals or dried tubers flour. In boiling, the leaves are softened and may be salted or mixed with butter before being fried to add flavor. The vegetable is often eaten with starchy foods such as stiff porridge. To enhance its mildly bitter taste, it is often cooked with other vegetables such as amaranth, cowpea, or pumpkin leaves, or with milk. 

In mashing with maize, the vegetable is cooked with maize, a mixture of maize, a pulse, pumpkins, or a starchy tuber like potato. These are mashed together, and butter may be added or the food fried. In cooking with cereals or dried tuber flour, the vegetable is boiled together with flour, and the mixture may be solid or semi-solid. In times of famine, the vegetable may be boiled and eaten with nothing else. In some communities, young pods and flowers are used in soups, but excessive consumption of the latter can cause drowsiness. 

a) Mitoo (Crotalaria sp.) and Mlenda (Corchorus sp.) with groundnut 

 

 

 

 

 

 

 

 

 

 

Ingredients

100 g Crotalaria leaves 
40 g jute mallow leaves 
2 tablespoonful traditional salt
1 tablespoonful or 20 g ghee or cow fat
1 tablespoonful groundnut 
½ cup water
Salt to taste
Preparation

Remove stalks off the leaves
Wash the vegetables and allow draining
Chop the vegetables roughly and mix them 
Add the traditional salt to the water and place on fire to boil
Add the vegetables, and boil them for 5 minutes. Keep stirring them as they cook 
Add the groundnut paste and ghee/cow fat then cook for 3 minutes
Serve hot with ugali
Variation

The same recipe is used when cooking Crotalaria and amaranth. However, two ingredients are eliminated i.e. traditional salt and groundnuts. Traditional salt is not used when cooking Amaranthus as it is a soft vegetable. Sour milk could however be used in place of ghee

Source: Cookbook for traditional vegetables (IPGRI, 2006). 

b) Mitoo 
Ingredients

2 bunches Crotalaria leaves (Crotalaria ochroleuca)
2 bunches of jute mallow leaves
1 bunch cowpea leaves
5 tablespoonful plant traditional salt 
2 cups water
Salt to taste
Preparation:

Remove the stalks off the vegetables, mix them all together and wash 
Add plant ash filtrate to water and let it boil for 5 minutes
Add vegetables to the boiling water and boil for 10 minutes under moderate heat
Add salt to taste
Serve with ugali
Remarks:

Frequent and continuous stirring causes mitoo to become more bitter. However, some people appreciate the taste. 

Crotalaria brevidens has been found to be more bitter than Crotalaria ochroleuca.

Many farmers do not recommend the use of the ordinary bicarbonate of soda, (Magadi soda) as they say it can be bad for the bones in the long run. This vegetable is common among the Luhya and Luo communities of Kenya. The dish is slimy and slightly bitter due to the 2 vegetables crotalaria.

Source: Cookbook for traditional vegetables (IPGRI, 2006). 

c) Fried mitoo

 

 

 

 

 

 

 

 

 

Ingredients

100 g Crotalaria
20 g onions 
30g (1 tablespoonful) butter/margarine
1 Cup  water
¼ cup fresh cream
Seasoning (optional)
Preparation

Remove the leaves off the stems and wash them
Bring the water to boil and add salt
Blanch the vegetables for 3 minutes
Drain the hot water, run cold water through the vegetable and drain
Heat the butter and fry the chopped onions slightly, without letting them brown
Add the vegetables, stir and allow cooking for 2 minutes
Add cream and seasoning of choice, stir
Serve with preferred starch and stew
Source: Cookbook for traditional vegetables (IPGRI, 2006).

 

 

Introduction

Cowpeas is an annual crop mainly grown for its leaves and seed. The growth habit is climbing, spreading, or erect. Cowpea is a very old crop. Africa is cited as the probable origin of the species based on the large genetic diversity of the cultivated and wild types. The crop exhibits much variation in growth habit, leaf shape, flower color, pod and seed size, shape and color. Cowpeas are important in warm marginal rainfall areas because they are well adapted to dry climates. Cowpeas are cultivated for the green or dried seeds and pods, leaves, pasture, hay, silage and green manure. Tender cowpea leaves and shoots contain about 4% protein and 4% carbohydrates and are rich in calcium, phosphorus and vitamin B. Dried seeds contain about 22% protein and 61% carbohydrates.

Cowpea leaves are widely consumed as vegetables in Africa. The vegetables may be cooked alone or with other vegetables. Jute mallow (Corchorus olitorius) is preferred because it helps soften the cowpea leaves. The vegetables are typically eaten with stiff porridge or mashed with maize, potatoes, or other pulses. In Botswana and Zimbabwe, boiled cowpea leaves are kneaded to a pulp, squeezed into small balls, dried and stored. Cowpea leaves may be preserved by sun drying or blanching and stored for several months.

In Africa, where cowpeas are the preferred food legume, the mature cowpea seeds may be cooked with vegetables, spices and often palm oil to produce a thick pulse soup, which accompanies the staple food (cassava, yams, plantain). In West Africa, the seeds are decorticated and ground into flour and mixed with chopped onions and spices and made into cakes that are either deep-fried or fried (Akara balls). The Immature, green and still soft seeds are cooked in a thick soup and used as a relish.

In addition to its use as human food, cowpea is used as a fodder crop for green feeding, haymaking, grazing and ensiling in a mixture of sorghum or maize. The roots are reportedly very poisonous. Various medicinal uses of cowpea have been reported. The root is used as an antidote for snakebites. For more on medicinal uses, see Grubben et al., 2004 and Madamba et al., 2006 (AVRDC & IPGRI, 2006).

Geographical distribution

Geographical distribution of cowpea. Source. https://www.gbif.org/species/2982583© OpenStreetMap contributors, © OpenMapTiles, GBIF

Vigna unguiculata originated in Africa, where a large genetic diversity in wild types occurs throughout the continent. It is the most important legume in the warm sub-humid and savanna areas of Africa. The greatest genetic diversity is found in West Africa, particularly in the savanna regions Vigna unguiculata originated in Africa, where a large genetic diversity in wild types occurs throughout the continent. It is the most important legume in the warm sub-humid and savanna areas of Africa. The greatest genetic diversity is found in West Africa, particularly in the savanna regions of Burkina Faso, Ghana, Togo, Benin, Niger, Nigeria and Cameroon. It has been introduced in Madagascar and other Indian Ocean islands. It is however less prominent in humid central Africa and the cooler highlands of Africa (Madamba et al., 2006; Schippers, 2000).of Burkina Faso, Ghana, Togo, Benin, Niger, Nigeria and Cameroon. It has been introduced in Madagascar and other Indian Ocean islands. It is however less prominent in humid central Africa and the cooler highlands of Africa (Madamba et al., 2006; Schippers, 2000).

General Information (Species account, Ecological Information)

Species account

Cowpea is an erect, trailing, or climbing annual or perennial herb. The flowers are of various colors, from pale green to light blue or purple, sometimes white or yellowish. The long, nearly cylindrical pod can range between 8 and 120 cm in length and may be straight or slightly curved, cream to brown or reddish purple when dry and 8-30-seeded. Seeds can be mottled or varying uniform colours ranging from white or cream to maroon or brown to black. The seeds of popular cowpea varieties, such as "black-eyed pea" and "pinkeye purple hull" typically have a white color with a circular, asymmetrical black or red pigmented region surrounding the hilum that gives the seeds the appearance of an eye (Madamba et al., 2006, AVRDC & IPGRI, 2006, Timko & Singh, 2008, Schippers, 2000).

Cowpea varieties and their characteristics

Cowpea has several subspecies that include both wild and cultivated types. Cowpea varieties may differ in habit, maturity period, yield, drought tolerance, resistance to disease and pests and weather good for seed or leaves and leaf and seed size. Preference may vary with the farmer (Omoigui et al., 2018, Madamba et al., 2006).

Examples of cowpeas varieties in Kenya

Variety	Days to Maturity	Target areas of production	Potential grain yield (t/ha)	Remarks
"Machakos 66" (M66)   Cowpea seed 'M 66.' (c) A.A. Seif, icipe	85-95	Mid altitudes 1200-1500 m above sea level	1.5-1.8	Dual purpose; creamy brown grains and suitable for intercropping; tolerant to cowpea yellow mosaic virus (CYMV) and scab; moderately tolerant to Septoria leaf spot and powdery mildew
"Katumani 80" (K80)    Cowpea seed 'K 80.' (c) A.A. Seif, icipe	75-85	Drier areas or areas below 1500 m above sea level receiving less than 200 mm of rain per season	1.8-2.0	Dual purpose; grains creamy brown; resistant to aphids; moderately tolerant to thrips, pod borers and leaf hoppers; susceptible to CYMV
"KVU 27-1"   Cowpea seed 'M 66.' (c) A.A. Seif, icipe	70-90	600 - 1200 m	1.5-1.8	Dual purpose; dark red grains; moderately tolerant to aphids, thrips, pod borers and leaf hoppers; moderately resistant to foliar fungal diseases and CYMV
"KVU-419"	65-72	Areas below 1200 m receiving less than 200 mm of rain per season	1.2-1.5	Grain variety; smaller seed than both "M66" and "K80"; tolerant to cold and recovers very fast from drought
"KVU HB 48E 10"	85-95	Medium and higher altitudes 1200-1500 m above sea level	1.2-1.4	More vegetable type than grain type; tolerant to virus diseases
"KCP 022"	60-75	0-1200 m	1.2-1.5	Drought tolerant
"MTW 63"	60	1-1500 m	2.5	Pest tolerant
"MTW 610"	60	1-1500 m	2.5	Large grains
"Kunde 1"	75-90	Below 2000 m	1.2-2.5	Dual purpose
"ICV"	75	1-1500 m	2.2	Pest tolerant
"Ngombe"				Semi-spreading, suitable for green leaf production, sweet taste of grain
Local varieties(land races)			0.3-0.5	Varying colors and spreading or semi spreading

Examples of cowpea varieties in Tanzania

• "Fahari" (altitude recommended: 0-1500 m; days to flowering: 50; yellowish grain brown; grain yield: 2.4 t/ha; resistant to CYMV
• "Tumaini" (altitude recommended: 0-1500 m; days to flowering: 48; grain cream; grain yield: 2.4 t/ha; resistant to CYMV and moderately resistant to bacterial blight
• "Vuli 1" (altitude recommended: 0-1500 m; grain red; grain yield:1.8-2.0 t/ha; resistant to CYMV and moderately resistant to bacterial blight
• "Vuli 2" (altitude recommended: below 1500 m; grain creamish white; grain yield: 2.0-2.5 t/ha; resistant to CYMV and bacterial blight; moderately susceptible to pests

Examples of cowpea varieties in Uganda

• "Amul" (local variety: regions: eastern and northern districts of Uganda; yield potential; 0.5 t/ha)
• "Apei" (local variety: regions: eastern and northern districts of Uganda; yield potential; 0.5 t/ha)
• "Apio" (local variety: regions: eastern and northern districts of Uganda; yield potential; 0.5 t/ha)
• "Ebelat" (local variety: regions: eastern and northern districts of Uganda; yield potential; 0.5 t/ha)
• "Icinkukwa" (local variety: regions: eastern and northern districts of Uganda; yield potential; 0.5 t/ha)
• "Katumani 80" (as in Kenya)
• "Kisyanka" (local variety: regions: eastern and northern districts of Uganda; yield potential; 0.5 t/ha)
• "IT82D-522-1" (new variety; yield potential: 4.5 t/ha)
• "IT85F-1987" (new variety: yield potential: 2.1 t/h"Amul" (local variety: regions: eastern and northern districts of Uganda; yield potential; 0.5 t/ha)
• "Apei" (local variety: regions: eastern and northern districts of Uganda; yield potential; 0.5 t/ha)
• "Apio" (local variety: regions: eastern and northern districts of Uganda; yield potential; 0.5 t/ha)
• "Ebelat" (local variety: regions: eastern and northern districts of Uganda; yield potential; 0.5 t/ha)
• "Icinkukwa" (local variety: regions: eastern and northern districts of Uganda; yield potential; 0.5 t/ha)
• "Katumani 80" (as in Kenya)
• "Kisyanka" (local variety: regions: eastern and northern districts of Uganda; yield potential; 0.5 t/ha)
• "IT82D-522-1" (new variety; yield potential: 4.5 t/ha)
• "IT85F-1987" (new variety: yield potential: 2.1 t/ha)

Examples of cowpea varieties in Nigeria

Variety	Yield (t/ha)	Other qualities	Agroecological zones
IT99K-573-1-1 (SAMPEA14)	2.6	Resistant to fusarium wilt and striga, tolerant to drought	Northern Guinea savanna, Sahel, Sudan savanna
IT99K-573-2-1 (SAMPEA15)	2.6	Tolerant to drought, resistant to striga	Northern Guinea savanna, as well as Sahel and Sudan savanna
UAM09 1055-6 (FUAMPEA 1)	1.9	Tolerant to drought, resistant to striga, short cooking time	Sudan savanna and Sahel region
UAM09 1051-1 (FUAMPEA 2)	2	Short cooking time, resistant to striga. Good for intercropping	Sudan and Northern Guinea savanna
IT89KD-288 (SAMPEA 11)	2	Resistant to nematodes. Good for intercropping	Northern Guinea savanna
IT07K-292-10 (SAMPEA16)	2.5	Tolerant to drought	Sudan savanna and the Sahelian region
IT07K-313-18 (SAMPEA17)	2.5	Tolerant to striga	Sudan savanna and Sahelian region
UAM14 130-20-4	2.2	Suitable for confectionary, Resistant to striga and alectra. Good for intercropping	Sudan and Guinea savanna
UAM14 127-20-	2	Suitable for confectionary, resistant to striga and alectra, Good for intercropping	Sudan and Guinea savannas
UAM14 123-18-3	2	Suitable for confectionary, resistant to striga and alectra,	Sudan and Guinea savannas
UAM14 126 19-2	2.5	Suitable for confectionary, resistant to striga and alectra. Good for intercropping	Sudan and Guinea savannas
UAM15 127-1-7	2	Suitable for confectionary, resistant to striga and alectra. Good for intercropping	Sudan and Guinea savannas
UAM15 137-1-7	2	Suitable for confectionary, resistant to striga and alectra. Good for intercropping	Sudan and Guinea savannas

Source: Guide to cowpea production in West Africa. (Published 2013) https://hdl.handle.net/10568/108728

Ecological information

Cowpeas are generally tolerant to drought and low light conditions but are very susceptible to various insects and diseases and do not do well in poorly drained and cool areas. Local landraces of cowpeas grown by farmers in West Africa are well adapted, so they start to flower at the end of the rains in a particular locality. The optimum temperature for their growth and development is 20 to 35 deg. C. Cowpeas can grow in a wide range of soils, are well adapted to light sandy soils where most other crops produce poorly and do well on acid soils. They show vigorous vegetative growth on heavily fertile soils but not necessarily a good grain yield. Most varieties need a minimum rainfall of 200 mm during a growing season.

Agronomic aspects

Planting

Land should be prepared to a fine tilth for good root growth. Generally, deep ploughing followed by harrowing provides an adequate tilth. Farmyard manure application is at the rate of about 36 tonnes/ha (360 kg per 10x10 m square). Sowing rates depend on the type. Creeping types need more space. Erect types of cowpea seeds may be planted about 20 to 40 cm apart if erect intercropped with pearl millet, sorghum, or maize. Tillage typically follows the crop with which cowpeas are interplanted. When produced as a green vegetable, they are commonly grown as a monocrop in rows 30 to 40 cm apart, with 8 to 12 cm between plants. These are then uprooted and sold once they have attained the right height. Some very drought-resistant creeping types, may grow for two seasons on the farm and hence the spacing will be more.

Row planting

Cowpeas are commonly grown mixed with other plants but can also be grown as a monocrop in rows.

The following is a basic procedure for row-planting erect cowpeas for uprooting:

1.         Make shallow furrows e.g. with a stick or finger. Leave about 20-30 cm between rows.

2.         Drop your seeds evenly as you move steadily along the row.

3.         Cover the seeds lightly e.g. by sprinkling fine soil on top.

4.         Water your seeds. Avoid washing them out of the furrows

Dryland water conservation measures

In Africa's arid and semi-arid areas, cowpeas can be grown in sunken beds or Zai pits to conserve moisture. Drip irrigation is also getting popular.

Growing cowpeas in planting pits and furrows

Planting pits or Zai pits (Zaï pits (Burkina Faso), Chololo pits (Tanzania), tassa (Niger), agun pits (Sudan), kofyarpits (Nigeria)) are popular in dryland farming especially around water sources. They are considered to be water-efficient farming technologies as they optimize water utilization by a crop. The size and configuration of the Zai pits are tailored to the type of crop being cultivated. By collecting irrigation or rainwater that would otherwise be lost due to runoff or percolation into unintended areas, the pits facilitate prolonged water retention, thereby allowing for gradual and more efficient usage by the crops.

How to make a Zai pit:

• Remove the topsoil and set it aside
• Continue digging to a depth of 45 cm to break the hardpan.
• Make sure the holes are dug running perpendicularly to the slope then putting the soil from the holes downslope (to create a small soil wall/bund to keep the water in the hole)
• Mix the topsoil with manure or compost and return it to the pit. Leave a depth of about 15 cm.
• Water the soil in the pit and plant the vegetable.
• (Source: Greener Land, June 2023; Maundu et al., 2022)

In dryland irrigated systems, cowpeas may also be grown in a system of furrows or basins or sunken beds. Irrigation water is filled in the furrows or basins. The seed is placed on the sides of the ridge in the case of furrows and on the floor in the case of a basin.

Sunken beds or basins may vary in size from about a square meter to several square meters. The shape may also vary from square to rectangular. Closed systems may accumulate salt with time and hence the need to allow rainwater to flush out the salt when it rains.

Raised beds in humid areas

In humid areas, cowpeas should be grown in well-drained soils or on raised beds. Beds are only suitable for erect cowpea plants, particularly those that are meant for the market.

The following procedure can be used while planting on raised beds.

1. Dig deep to loosen the soil and break any hardpan.

2. Prepare your raised beds, each 1 m wide. Leave 30 cm furrows for drainage and stepping on while working, e.g., weeding and watering the plants.

3. Avail enough water and well-cured compost or manure. Cattle-based manure retains potency for much longer than most other domestic animals. Donkey-based manure is of poor quality.

4. Mix the topsoil with manure evenly. A bucket of manure per square meter is sufficient.

5. Level the bed again. A hoe handle does an excellent job of leveling.

Husbandry

Most cowpea crops are rain-fed, a few are irrigated and others use residual moisture in the soil after the harvest of a rice crop or receding river or dam water. Cowpeas are particularly well suited for rice-based cropping systems. Parasitic weeds, such as Striga gesnerioides (Purple witchweed), generally associated with the continuous cropping of cowpeas in Africa, may also cause severe damage. One additional benefit of cultivating cowpeas is their ability to fix atmospheric nitrogen in root nodules through symbiosis with Rhizobium bacteria that are common in most soils. An effective Cowpea-Rhizobium symbiosis may fix more than 150 kg/ha of N and may supply 80-90% of the total N required.

Inoculation may be advantageous if the crop has not been grown for many years. In general, no fertilizers are applied. Cowpeas are commonly incorporated in crop rotations in most places where it is cultivated. A cowpea crop of the leafy types grown before a maize or millet crop and incorporated green into the soil can produce a good grain crop without any addition of more nitrogen. Intercropped cowpeas also share nitrogen with other crops, e.g., maize, millet, sorghum and cotton. For intercropping, choose a cowpea variety carefully - the spreading types may overpower other crops, such as cotton, by entangling their branches and interfering with fieldwork. Cowpeas do not normally respond to nitrogen or phosphorus fertilizers, so none need to be added. However, where soils are highly eroded, an application of 4.5 tonnes/ha of dry compost or manure is beneficial. Weed during the crop's early stages, the cowpeas will later cover the ground and suppress weeds, including purple witchweeds.

Introduction

The common bean, Phaseolus vulgaris, is a herbaceous annual plant in the family Fabaceae which is grown as a pulse and green vegetable. Beans are cultivated widely worldwide, forming one of the most significant food sources in Africa and Latin america. Beans were introduced to Africa from Latin America several centuries ago. To date beans are a vital staple in Africa, providing the main source of protein. Beans are consumed in many forms; the young leaves, green pods, and fresh bean grains are used as vegetables. Consumption of bean leaves is reported from the tropics from southern and eastern Africa: South Africa, Zimbabwe, Zambia, Malawi, Tanzania, Kenya and Uganda.

Pulse crop ; In tropical Africa common bean is primarily produced and consumed as a pulse. The mature dry seeds of common bean are eaten worldwide as a pulse and the immature pods and seeds as a vegetable. In tropical Africa the bean is most typically consumed boiled, often with seasoning and some oil added. It may also be mashed or made into soup. In many parts of the world the dry seeds of common bean are canned, either alone or in tomato sauce.

Leafy vegetable; Common bean leaves are eaten as a vegetable, e.g. during the hunger months of the year when not much food is available. Consumption of the bean leaves is more prevalent in the cooler highlands of east and southern Africa.

In South Africa, the leaves are commonly eaten as a cooked green called moroqo or m'fino. In the inland highveld, the bean leaves is dried in the sun to store for the dry season. Dried morogo is frequently available year-round, in urban as well as rural markets.

The Shona, Kaianga and Zezuru people of Zimbabwe eat Bean leaves as cooked greens regularly, with a peanut paste or stew when available. In Zambia, fresh bean leaves are cut up and boiled with salt or trona (crude sodium carbonate) and eaten immediately, or dried in the sun for two or three days. In Malawi bean leaves are harvested during the pod filling stage. The fresh leaves are sundried on mats and stored in sacks. Although young leaves are preferred, older leaves are also eaten, usually cooked with sodium carbonate, trona or potash to soften them. The Chewa and other peoples eat bean leaves with peanut paste or stew

In Uganda, bean leaves are commonly eaten fresh-cooked and are dried for dry season consumption. They are used to supplement the staple food dish as a sauce, a relish added to meat and fish, and mixed with the bean seed itself. In Kenya, bean leaves are important in the higher rainfall areas where most beans are grown. Intercropping is the standard practice, usually in rows between other crops, but sometimes in small patches. The leaves are steamed, boiled or fried alone or in combination with other vegetables, depending on use and availability.

Various local spices and trona may be used to alter the leaves' consistency. Most are eaten as an accompaniment to a high-carbohydrate food stuff such as maize, sorghum, cassava, banana, etc. However in Kenya, bean leaves are not an important market commodity, even at the local level, although some will be sold, particularly in drier areas or in periods of famine or shortage.(The Beannicowpea collaborative research support program (CRSP), n.d.)

Livestock fodder; Crop residues are often used as fodder.

General Information

The common bean is typically a climbing, trailing or erect and bushy annual herb,depending on the variety being grown. The leaves grow alternately on the stems, are green or purple in color and are divided into 3 oval leaflets with smooth edges. The leaves can grow 6–15 cm long and 3–11 cm wide. The common bean produces white, pink, lilac or purple flowers which are approximately 1 cm in diameter, and bean pods 8–20 cm long and 1–1.5 cm wide which can range in color from green to yellow or black to purple. Each pod contains 4-6 smooth, kidney-shaped beans. Common bean plants are annual plants and last only one growing season and range greatly in size from the bushy varieties 20–60 cm in height; to vines or runner beans which can reach 200 –300 cm in length. (Wortmann, C.S., 2006)

Common beans do well in regions with temperatures between 15 and 27°C. The crop can tolerate the maximum temperatures of about 29. 5°C. Temperatures close to or above 35°C, and stress due to moisture during the flowering stage and pod formation may cause abortion effects to several blossoms and under development of new pods. The sufficient conditions necessary for beans growing are; rainfall range between 350 and 500 mm and relatively low humidity. Low humidity and enough rainfall are significant in controlling the risks associated with bacterial and fungal diseases.

Common bean (dry bean) varieties in Kenya 

 

Variety	Optimal production altitude (m)	Maturity period (months)	Grain yield (t/ha)	Remarks
"Canadian Wonder (GLP 24)"	1200-1800	3.0	1.3-1.8	Seeds are shiny dark reddish purple, recommended for medium rainfall areas, resistant to angular leaf spot (ALS) and anthracnose but susceptible to common bean mosaic virus (CBMV) and rust
"KAT/B-1"   Dry beans seed KAT BI  Ⓒ A.A. Seif, icipe	1000-1800	2.5	1.4-1.9	Seeds creamish-green, tolerant to ALS, common bacterial blight (CBB) and CBMV, tolerant to drought and heat and grows well under tree/banana shades
"KAT/B-9"	900-1600	2.5-3.0	1.0-1.8	Seeds brilliant red, more drought tolerant than KAT/B-1, tolerant to CBMV and rust
"KAT X16"	900-1600	2-3	1.5-1.8
"KAT X56"	900-1800	2.5-3.0	1.5-1.8	Seeds brilliant red, tolerant to CBMV, charcoal rot and rust
"KAT X69"	1200-1800	2-3	1.5-1.8	Seeds red with cream flecks, resistant to CBMV and rust, tolerant to ALS and charcoal rot, susceptible to lodging
"Kenya Wonder"	1000-2000	3.0-3.5	1.1-2.1	Moderately resistant to ALS, CBB, CBMV and halo blight (HB)
"Kenya Red Kidney"    Dry beans seed Kenya Red Kidney Ⓒ A.A. Seif, icipe	1000-2100	2.5-3.0	1.1-2.8	Moderately resistant to ALS, CBB, CBMV and HB
"KK 8"	1500-1800	2.5-3.0	1.8-2.0	Tolerant to root rot
"KK 15"	1500-1800	2.5-3.0	1.8-2.0	Tolerant to root rot
"KK 22"	1500-1800	2.5-3.0	1.8-2.0	Tolerant to root rot
"Miezi Mbili"	1000-2000	2.5-3.0	1.2-2.3	Moderately resistant to ALS, anthracnose, CBB, CBMV and HB
"Mwezi Moja (GLP 1004)" Figure 2; Bean. Mwezi Moja (GLP 1004). Machakos.P Maundu	1200-1600	2-3	1.2-1.5	Well suited for the drier semi-arid low rainfall areas and also performs well in medium rainfall areas during short rains, seeds are large beige or light brown speckled purple, tolerant to drought and bean fly but susceptible to HB
"Mwitemania (GLP X92)"	900-1600	2-3	1.2-1.5	Wide adaptability to various agro-ecological zones of low to high rainfall areas, seeds broad with brown flecks on cream, susceptible to CBMV, drought tolerant
"New Mwezi Moja (GLP X1127)"	1000-1500	2.5-3.0	1.0-1.5	Wide adaptability, resistant to CBMV, tolerant to rust
"Pinto Bean (GLP 92)"	100-1500	3.0-3.5	1.2-1.7	Wide adaptability, resistant to HB
"Red Haricot (GLP 585)"	1500-2000	2.5-3.0	1.0-1.5	Suitable for high rainfall areas, resistant to CBMV
"Rose Coco (GLP 2)" Figure; Beans-rose coco (GLP 2) (Green P Maundu)	1500-2000	3.0	1.8-2.0	Wide adaptability, recommended for medium and high rainfall areas, seeds red with cream flecks, resistant to anthracnose and CBMV but susceptible to ALS and rust
"Wairimu Dwarf"	500-1700	2.5	1.5-1.7	Heat tolerant, good for maize intercropping, excellent cooking qualities

 

Examples of common bean varieties grown in Tanzania

• "Canadian Wonder" (characteristics as in Kenya) 
• "Cheupe" (recommended altitude:above 1500 m, potential yield: 2.5-3.0 t/ha, seeds light brown, resistant to anthracnose, CBMV, HB and rust)
•  "Lymungo 85" ((recommended altitude: 900-1800 m, days to flowering: 33, pod colour: yellow, potential yield: 1.2-1.5 t/ha, resistant to ALS, anthracnose, CBB and CBMV)
• "Lymungo 90" (recommended altitude: 900-1800, seeds are larger than Lymungo 85, colour deep mottled red purple, yield potential; 1.2-1.5 t/ha)
•  "Selian 05" (recommended altitude: 1000-1500, potential yield: 1.0-1.6 t/ha, seeds cream in colour, resistant to anthracnose, CBMV, HB and rust) 
• "Selian 06" (recommended altitude below 1500 m, yield potential; 2.5-3.0 t/ha, seeds white, days to flowering: 40, resistant to anthracnose, CBMV and HB)

Examples of common bean varieties grown in Uganda

•  "K 132" (Seeds large kidney shaped red with white mottled colour, maturity period: 80 days, potential yield: 2 t/ha, resistant to CBMV but susceptible to anthracnose)

 Commercial varieties of French beans available in Kenya

Variety	Resistance to diseases
"Alexander"	Anthracnose, common bean mosaic virus, rust
"Amy"	Anthracnose / common bean mosaic virus
"Emelia"	Anthracnose / common bean mosaic virus / halo blight
"Julia"	Anthracnose / common bean mosaic virus
"Lausanne"	Anthracnose / common bean mosaic virus
"Paulista"	Anthracnose / common bean mosaic virus / common blight /
"Olivia"	Common bean mosaic virus
"RS 1389"	Common bean mosaic virus / bean rust
"RS 1391"	Common bean mosaic virus / bean rust
"RS 1518"	Anthracnose / common bean mosaic virus
"Samantha"	Anthracnose / common bean mosaic virus
"Tanya"	Anthracnose / common bean mosaic virus / halo blight
"Xera"	Anthracnose / common bean mosaic virus

                                           

Source: PIP Technical Itinerary French Beans. www.coleacp.org

Recently introduced French bean varieties in Kenya (HCDA)

• "Bakera"
•  "Bronco"
•  "Claudia" 
• "Coby" 
• "Cupert"
•  "Espadia"
•  "Gloria" 
• "Morgan"
•  "Pekera"
•  "Rexas" 
• "Sasa"
•  "Super Monel"
•  "Tonivert" 
• "Vernando" 

Agronomic aspects

Planting Time/Period

Beans are susceptible to extreme temperatures but do well in warm seasons. During low temperatures, plant growth is relatively low as compared to high temperatures, which records an accelerated growth rate. The plants have high adaptability to short days because they are very frost-tender, with an average minimum soil temperatures of about 18°C for better germination. Sowing of bean plants should therefore be after the last dates of frost-free. When sowing, it is essential to take account of the temperatures and the length of days to ensure favorable growing conditions. Most types of beans require a frost-free growing season of 85 to 120 days (Dulloo, M. E., et al., 2008, Claessens, n.d.)

Planting

Common bean is normally propagated by seed, the seeds may be sown by broadcasting and row planting. Sole-crop sowing rates range from 150,000–400,000 seeds per ha. With intercropping, sowing rates are less than for sole cropping (Wortmann, C.S., 2006).

Bush beans (Erect and bushy type) should be planted in rows 60–90 cm apart with 5–10 cm spacing within the rows. The climbing common bean (Pole bean type) is sown 3–6 seeds per planting hole in rows 100–120 cm apart with 40–50 cm spacing within the row. Seeds are normally sown 3–4 cm deep, but as deep as 7 cm if the soil surface is dry and not too heavy or prone to crusting. Climbing bean cultivars are more often produced in sole cropping than non-climbing types. The dense foliage in sole cropping easily creates a humid environment promoting diseases. Common bean is sometimes grown as a relay crop on residual moisture, e.g. in Malawi and southern Tanzania or intercropped with other annual or short-lived perennial crops like maize, bananas and root or tuber crops.(Wortmann, C.S., 2006, Bean | Diseases and Pests, Description, Uses, Propagation, n.d.)

Crop Management

The climbing bean type (Pole beans) should be provided with a pole or trellis to climb on to support the weight of the pods and allow light to penetrate to all parts of the plant, helping to prevent disease.

The crop is usually weeded once or twice, after which its canopy is sufficiently developed to suppress weeds. Earthing-up is often done at about 3 weeks after sowing. This should be done carefully, because common bean is liable to damage to the collar of the plant. Irrigation is uncommon except at higher latitudes with winter (dry season) production (Wortmann, C.S., 2006, Bean | Diseases and Pests, Description, Uses, Propagation, n.d).

Beans are comparatively light feeders and require as a guide line about 25-35 kg P/ ha (equivalent to 1-2 bags of Mijingu rock phosphate/ha) and 75-80 kg K/ha. Like all legumes, beans are able to fix nitrogen from the atmosphere, so do not require nitrogen fertilization. However, a soil conducive to nitrogen fixing with the natural nitrogen fixing bacteria present is preferable. Hard soils with little organic matter will not give good yields of beans, unless organic matter is provided, preferably in the form of good quality compost or well decomposed farmyard manure. For pure stands of beans, it is preferable to construct slightly raised beds of maximum 1 metre width in order to limit soil compaction around the bean plants. Application of good compost in the beds will improve yields as it will improve nitrogen fixation. Timely and thorough weeding is essential for French beans.

The first weeding should be done 2-3 weeks after emergence followed by a second weeding 2-3 weeks later. During weeding slight ridging of plants will help bean plants withstand attack of bean flies. Cultivating beans when the soil is wet encourages spread of soil-borne diseases such as anthracnose and fusarium root rot. Shallow tillage is preferred especially in the period before flowering as damage to the roots or the collar of the plant encourages soil borne diseases. Common bean can be rain-fed or irrigated. Irrigation is beneficial in semi-arid regions, with overhead irrigation preferred over flood irrigation. In peasant farming, the crop is seldom manured. Crop rotation is necessary to limit soil borne diseases such as root-knot nematodes and fusarium root rot. Fertilise the soil properly and plant French beans on hills or ridges where root rot could be a problem. Avoid furrow irrigation in areas prone to root rot and root-knot nematodes and fusarium. 

Mulching 

Mulching with straw and cut grasses helps conserve moisture, promote adventitious root development and enhances tolerance to bean fly maggot damage. 

Intercropping

Beans are excellent for intercropping with other food crops, such as maize, potatoes, celery, cucumber and can help supply the other crops with nitrogen to a limited degree. Longer season varieties of beans can fix higher amounts of nitrogen than short season varieties. Intercropping with chives or garlic helps repel aphids (KIOF - personal communication). 

Water management 

A regular water supply is essential for French beans as moisture affects yields, uniformity and quality. Water stress during flowering reduces yields, as does waterlogging. Irrigation in dry spells is recommended as 35 mm per week at planting and 10 days post emergence, followed by 50 mm per week thereafter till end of production. 

Pest and disease prevention with EM or BM 

EM (Effective Microorganisms) and BM (Beneficial Microorganisms) have been shown to prevent many diseases and a few pests in various crops when sprayed on a regular basis. These are commercial products and are readily available in Kenya. It is organically acceptable and quite cheap. 

Harvest/Post Harvest Practices

 

     a. Harvest

Common bean may be harvested while most pods are still green but near physiological maturity, for an early harvest of a fresh, easy to cook pulse product, but most crops are harvested when mature. French beans are harvested before the pods are fully-grown. Harvest starts 7-8 weeks after sowing in early cultivars. Pods should be picked every 2-3 days, and the number of pickings is greater in climbing than in bushy cultivars. Dry beans are harvested as soon as a considerable proportion of the pods (roughly 80%) are fully mature and have turned yellow. Some cultivars tend to shatter. Usually entire plants are pulled and further dried till ready for threshing. After threshing the beans are further sun dried to estimated 12 % moisture to avoid storage problems.

When leaves are used as a vegetable, the plant is usually not left to set seed but uprooted before flowering at three to five weeks of age. Occasionally, the leaves are picked just prior to senescence when the pods are full but not yet dry. In this case both leaves and seeds are used. The tender leaves are plucked and the shoots left to continue growing. Harvesting of the bean leaves should stop once the plants begin to flower. 

Farmer practices:

Solar drying of bean seeds before storage is essential. Also before storing, mix bean seeds with a) ashes or ash/chilli mixture b) diatomite (commercially available as Kensil Lagging from most hardware shops in Kenya) c) store completely dry seeds in a sealed container such as a metal or plastic bucket with air tight lid, checking regularly that no weevils are developing and closing tightly again.

     b. Post Harvest

The bean leaves is preserved through blanching to make them available during the dry season. To dry the bean leaves, spread themon a mat on the sun and regularly turn the leaves to allow them dry evenly. Store the dried leaves in a cool and dry place The dried leaves can be used any time of the year as a food resource.

 

Nutritional value information, Complimentary recipes

 

 1. Recipe 1- Bean Leaves in Groundnut Sauce (Chimpapila)

Ingredients

• 1.5 grams fresh beans leaves
• 400 grams groundnuts pounded
• 150 grams tomato
• 50 grams onion
• salt
• water

Cooking procedure

• Pluck leaves from the stems and wash in cold water
• Put in sauce pan, bring to boil and cook 15 minutes
• Make groundnut paste and add to the vegetables
• Add salt and keep stirring for 20 minutes to allow groundnuts to cook
• Add chopped tomato and onion and immediately remove from fire
• Stand 5 minutes and stir to blend the mixture together

Serving for 6

Recipe from Zambian Cookbook, by Sylvia C. Banda and Hector H. Banda published by CARE International in Zambia.

2. Recipe 2

Ingredients.

• Beans leaves 250gm
• 50 gm grated coconut
• 1 piece ginger
• 1 Onion
• 1 teaspoon Mustard seeds
• 1 Tablespoon Oil, preferably coconut oil
• 50 gm Raw peanuts 

Instructions.

1. Wash and cut the bean leaves into small pieces.
2. Fry mustard in the oil, once the seeds are broken, add onion, peanuts, and grated coconut into the pan.
3. Keep stirring until the grated coconut turns brown. Add the bean leaves and ginger bits into the pan.
4. Mix with salt, if you need, cover it and cook, low flame, in the steam from the leaves.
5. Shut the pan. Ready in 6 minutes It's a dry preparation.
6. If you have fresh curry leaves, chuck them in during the last two minutes of cooking.

 

Introduction

Adansonia digitata, commonly known as the African Baobab, is a highly adaptable and drought-resistant fruit tree found in the arid and semi-arid regions of Sub-Saharan Africa. It is the sole species of the Adansonia genus in tropical Africa, distinguishing it from the other eight species found in Australia, Madagascar, and various islands in the South Pacific and Indian Ocean. Despite being a softwood tree, the African Baobab stands out as one of the longest-living trees, with a lifespan of up to 3,000 years. It possesses exceptional traits that enable it to thrive in dry climates, including an extensive root system, high water retention capacity, and early leaf shedding. Its smooth bark provides excellent resistance to drought and fires.

Within African communities, the Baobab tree and its products hold varying significance for sustenance and income generation. The baobab leaves, which are highly nutritious and rich in essential nutrients such as calcium, potassium, and vitamin C, are a popular vegetable in local communities throughout Africa. In the savannahs south of the Sahara, baobab leaves are widely consumed, making them one of the most common food sources between Senegal and Lake Chad. It is worth noting that although baobab trees are found in Eastern and Southern Africa, the leaves are rarely consumed in these regions.

Baobab leaves are harvested fresh and cooked as a potherb in some areas, while in others, they are dried and crushed for later use. These leaves have a unique taste that is slightly sour, tangy, and sweet, with hints of nuttiness or earthiness. When cooked, their flavour becomes mild and reminiscent of spinach. They have a slightly tough and fibrous texture, and the mucilage released during cooking gives them a slightly slippery and slimy consistency. Baobab leaves are commonly added to soups, stews, sauces, and relishes, enhancing the flavour and nutritional value of the dishes while also thickening them. They are frequently served as a side dish, similar to spinach, and poured over various staple foods such as yam, cassava, maize, millet, sorghum, etc., to complete the main meal.

Baobab leaves have also been found to possess various medicinal properties. In traditional African communities, powdered baobab leaves are commonly used by traditional healers to treat ailments such as asthma, fever, malaria, smallpox, and diarrhoea. Studies have demonstrated their potential as anti-inflammatory, antipyretic, anti-diarrheal, and antiplasmodial agents. Furthermore, these leaves exhibit remarkable antioxidant properties, further adding to their therapeutic potential. Further research is necessary to determine the safety and effectiveness of using baobab leaves for medicinal purposes in humans.

During the rainy season, baobab leaves serve as a vital source of sustenance for domestic livestock and wild animals, including elephants and impalas, especially when grazing lands are depleted and new growth has yet to emerge.Furthermore, the baobab leaves are a significant source of food for animals, and the tree itself provides habitats for many wild animals, contributing to the preservation of biodiversity in the region. Additionally, the tree provides other ecosystem services such as carbon sequestration, soil enrichment, air and water quality improvement, and biodiversity conservation (Hankey, 2004).

(National Academies of Sciences, 2006, Hankey, 2004, Alao et al., 2016, Maundu & Tengnas, 2005).

 

General Information

Species account

Adansonia digitata is a succulent, deciduous tree that can grow up to around 20 meters tall, often with a very sparse crown, especially in the drier parts of its range. The swollen, urn-shaped bole eventually becomes very wide, often exceeding the diameter of the crown, and can be up to 10 meters across. The stem is covered with a bark layer, which may be 50-100 mm thick (Fern, 2021). Bark; is greyish brown and usually smooth but can often be variously folded and seamed from years of growth. Leaves; are hand-sized and divided into 5-7 finger-like leaflets. Flowers; The flowers are large, white, or yellow, with prominent stamen protruding over crinkled petals and sweetly scented. They emerge in the late afternoon from large round buds on long drooping stalks in early summer. Large, egg-shaped Baobab fruits develop at the early stages of growth. Fruits; are green in color, turning brownish-grey as the fruit ripens. Unlike the flowers, the fruits hang pendulously off the branches on long pedicels (Hankey, 2004).

 

The mature fruit consists of a hard, woody outer shell covered with yellowish-brown hairs that feel velvety. They exhibit different forms; small and big, tapered and rounded, and even the fruit skin hair hue. The fruit contains red-brown and coarse fiber that crisscross the fruits and holds creamy powdery fruit pulp. The fine pulp covers large kidney-shaped seeds. Roots; Baobab tree produces an extensive network of lateral roots that end in tubers. The seedlings produce prominent taproot, which is quickly replaced by laterals. Roots of mature trees rarely extend beyond 2 meters and are relatively shallow, which is one reason why old trees frequently fall over. 

 

Ecological information

Annual rainfall: Baobabs are most common, where mean annual rainfall is 200-1,200 mm. However, they are also found in locations with as little as 90 mm or as much as 2,000 mm of mean annual rainfall.

Altitude: The Baobab is usually found in elevations ranging from 0-1,300 m above sea level.

Soil type: The tree grows on a wide range of soils; however, A digitata shows a preference for acidic, well-drained soils (pH <6.5), preferably with sandy topsoil's overlaying loamy substrates (Orwa et al., 2009).

Temperature: Baobab thrives where the mean annual temperature is 20-30°C. It succumbs to frost. Reportedly, germination is achieved only when soil temperature exceeds 28°C (National Research Council, 2006).

 

Agronomic aspects

Natural propagation

The Baobab tree's natural regeneration process is impeded by multiple factors, including browsing animals, prolonged drought, and uncontrolled bushfires. Furthermore, the seeds exhibit low germination rates, with the process naturally taking several years to initiate, often requiring fire to break dormancy. In addition to this, the digestive tract of mammals such as elephants and baboons can facilitate seed dormancy breakage, thereby contributing to the Baobab's natural propagation (Maundu & Tengnas, 2005).
 

Growing Baobabs from seeds

The propagation of African baobabs is predominantly achieved through seed germination, which requires specific conditions to be effective. Mechanical scarification is a crucial step for successful germination, as the seeds have a hard and thick seed coat that hinders water absorption, resulting in a prolonged emergence period of up to several year.

According to Maundu and Bo Tengnas (2005), seed germination of Baobab trees can be induced by fire, as the heat softens the seed coat, thus allowing water to penetrate the seed. Other methods of scarification include soaking the seeds in hot water, cutting or sanding the seed coat, or exposing them to sulfuric acid. These methods have been found to increase germination rates and shorten the time required for seedling emergence. It is important to note that seedling growth can be slow, and seedlings require a well-draining substrate to thrive. Once the seedlings have developed into saplings, they can be transplanted into their permanent locations. Air layering, grafting, and cuttings also been successfully utilized and are considered less costly but less effective. (Sidibe & Williams, 2002; Arum, 1989).
 

Seed collection

To collect Baobab seeds, one can either retrieve them from fruits that have fallen off the tree or use poles and sticks to dislodge fruits from the tree's canopy. Once collected, the seeds should be air-dried and stored in clean, dry, and labelled containers in cool, dry places to prevent damage from moisture, insects, fungal infections, rats, and mice. However, collecting seeds from fallen fruits may not be effective as the seeds may have lost viability or become infected. For shorter trees, seeds can be harvested from the ground or by climbing up a ladder. It is important to note that the collection method can affect the seed's quality, and careful selection of seeds is necessary for successful propagation (Sidibe & Williams, 2002; Arum, 1989).
 

Planting

Seed pre-treatment is a crucial process that can significantly impact the germination rate of baobab seeds. Scarification with concentrated sulphuric acid for 6-12 hours is a common pre-treatment method that has been shown to result in a germination rate of over 90%. However, in rural areas, manual scarification or boiling seeds in water for 15 minutes can be used as an alternative.

Direct seeding into the field has not proven to be very successful, so it is recommended to raise seedlings in a nursery potting mixture of topsoil, sand, and compost. (3 parts topsoil, 1 part sand, and 1 part compost); they can be sown in beds, pots, or polybags. The germination of baobab seeds can be sporadic and take up to a month. Once seedlings emerge, they should be shaded for 8 days, given half shade for 4-7 days, and then exposed to full light after 12-15 days.

Baobab seedlings should be transplanted at the beginning of the rainy season when they are at least 3-4 months old and have reached a height of 40-50cm. Seeds should be sown 1 to 2 inches deep, and soil temperature should be maintained at a minimum of 15 degrees Celsius. Soil should be kept evenly moist but not wet. Planting should be done at a spacing of 10m x 10m. After transplanting, it is crucial to protect the baobab trees from game, livestock, and fire until they are well established (Sidibe & Williams, 2002, Arum, 1989).
 

Tree management

The tree should not be planted near houses. Lateral roots may reach over 100m. Pollarding can increase leaf production and prevent toppling of hollow trees, but may reduce fruit production for a few years.

 

 

Pest and disease management

Baobab trees have a natural resistance to pests and diseases and are able to withstand environmental stressors due to their thick bark, water storage capabilities, and adaptability. While baobab trees are generally hardy and resistant to pests and diseases, some pests, fungal and viral diseases can affect the tree, and several insect pests that can attack the wood, fruit, and young shoots.

 

Information on pests

The Baobab tree supports a diverse ecosystem with wide range of insects that do not significantly affect its productivity. While the Baobab tree itself may remain resilient, nearby cultivated crops or native plants could become susceptible to infestation or damage by these pests. It is crucial to monitor and manage pest populations to mitigate potential negative impacts on the surrounding flora. Some of the common Pest that inhabit pests include:
 

Cotton Bollworm (Helicoverpa armigera)

The cotton bollworm is a destructive pest that affects a wide range of crops, including cotton. The adult moth has a wingspan of around 3-4 cm and has mottled brown or gray wings. The larvae are caterpillars that vary in colour from green to brown or pinkish and have distinct longitudinal stripes along their bodies.

What to do:

• Encourage natural predators of the cotton bollworm, such as parasitic wasps, ladybugs, and birds, by providing habitat and avoiding the use of broad-spectrum insecticides.
• Regularly monitor the trees for signs of infestation and remove any affected fruits or larvae by hand.
• Proper sanitation practices, such as removing fallen fruits and plant debris, can also help reduce the population.
• Natural insecticides derived from plants, such as neem spray or a garlic-chilli-onion-repellent and Bt, can be used as organic alternatives to control cotton bollworms.

   

Cotton Strainer Bugs (Dysdercus spp.)

Cotton strainer bugs are true bugs that are primarily known for their damage to cotton crops. Stainer bugs are between 14 and 24 mm long. They are bright red, yellow or light grey with an orange tinge depending on the species, and with black bands. Stainer bugs are late season pests. They appear when the bolls are ripening. Female lays whitish yellow eggs in moist soil or in crevices in the ground. They hatch to produce reddish-orange nymphs. Initially the nymphs are wingless, but wings develop gradually as the nymphs grow. The nymphs are found together in the area where the eggs have been laid and later disperse to look for food. Both nymphs and adults feed on the bolls, but adults cause the most serious damage. They pierce through the boll and suck the seeds reducing germination capability and the quality of the seed oil and the cake. Furthermore, they cause severe indirect damage by transmission of a fungus (Nematospora sp.), which leads to internal boll rot and stain of the lint with typical yellow colour, hence the name 'cotton stainers'.

What to do: Cotton stainers are attacked by a range of natural enemies. The most important are assassin bugs, ants, spiders, birds and parasitic flies. If cotton is grown where baobab occurs, the soil and trunk of the baobab tree should be sprayed to kill the nymphs hatching from eggs laid around the stem. Introduce natural predators of cotton strainer bugs, such as predatory bugs and parasitic wasps, to the Baobab tree's ecosystem to help control the pest population. Neem oil or neem-based insecticidal sprays can be used as an organic control method. Ensure thorough coverage of the affected areas, including the undersides of leaves and stems.

 

 

Information on diseases
 

Sooty mould (Antennulariella sp.)

This disease manifests itself through the appearance of orange-brown spots primarily on the undersides of branches. As the infection progresses, these spots darken and merge to form larger patches, giving the affected areas a blackened appearance.

Reports of sooty mould affecting baobabs have emerged from various regions in southern Africa, including Malawi, South Africa, Zambia, and Zimbabwe. The presence of black mould on the stems and branches of African baobabs has been closely associated with a decline in the health of these remarkable trees. Fortunately, sooty mould fungi do not penetrate beyond the outer layer of the baobab's bark, known as the epidermis. While in severe cases, the extensive growth of the fungi on leaves can hinder the plant's photosynthetic ability, it does not directly interact with the plant cells to elicit a physiological response (Chomnunti et al., 2014, Hughes, 1976, Cruywagen et al, 2015).

What to do:

• Regular pruning helps remove heavily infested branches or parts of the tree where honeydew and sooty moulds are prevalent. Pruning also promotes better air circulation and sunlight penetration, creating an unfavourable environment for the growth of sooty moulds
• Maintain proper sanitation practices in the vicinity of the Baobab. This significantly reduce the chances of fungal spores being transported to healthy trees. This entails clearing away fallen leaves, debris, and other organic matter that may serve as potential breeding grounds for the fungi.
• Furthermore, promoting optimal tree health through appropriate watering, adequate nutrition, and preventing any physical damage to the baobabs can enhance their resilience against sooty mould infections.

 

 

Harvesting, post-harvesting practices and value addition

 

Harvesting baobab leaves

The baobab tree displays an impressive burst of foliage at the onset of the rainy season, remaining green throughout the rainy-to-harvest season. In healthy trees, the colour of the leaves is a strong green, in some even dark green. Freshly emerging leaves are light green, but darken over time.

Fresh young baobab leaves are harvested, with people often climbing the trees to pluck every tender leaf within reach. In some instances, ladders or steps are cut into the tree's side to allow easy access to the upper parts. While some trees are kept denuded throughout their life, others are pollarded, with their top branches cut back to the trunk, inducing dense growth of new shoots. Towards the end of the rainy season, the leaves are harvested and sun-dried for domestic use and marketing during the dry seasons. The drying process involves leaving the leaves whole or pounding and sieving them into fine powder (National Academies of Sciences, 2006, Sidibe & Williams, 2002).

 

Post-harvest practices

Different communities employ distinct methods of post-harvest handling. In Zimbabwe, Baobab leaves are harvested and sundried before being ground into a powdered form for utilization as a soup thickener. In Mali, the leaves are powdered and used in the production of a local soup known as Lalo, which is sold in West Africa. In northern Nigeria, the leaves are utilized in the preparation of Miyan Kuka, a soup commonly consumed by the Hausa tribe (Asogwa et al., 2021).

Effective post-harvest handling plays a critical role in preserving the quality of Baobab leaves. It is essential to store the leaves in a cool, dry, and well-ventilated environment to prevent moisture absorption and subsequent spoilage.

 

Value addition and market value

Baobab leaves are used in various ways such as in soups, stews, sauces, and as a vegetable. They can also be dried and ground into a powder that can be used as a food supplement or added to smoothies.

The market value of Baobab leaves is increasing due to the growing demand for natural and organic products. In some African countries such as Senegal and Zimbabwe, baobab leaves are sold at local markets for up to $10 per kilogram. The leaves are also exported to other countries such as Europe and the United States where they are used in the production of herbal teas and supplements (Rashford, J, 2018).

 

Nutritional value and recipes

Baobab leaves are a nutritional powerhouse, containing high amounts of calcium, magnesium, phosphorus, potassium, vitamins A and C, beta-carotene, and folate. Calcium is essential for maintaining strong bones and teeth, while magnesium is important for nerve and muscle function, regulating blood pressure, and maintaining a healthy immune system. Phosphorus is necessary for energy production and bone health, and potassium is crucial for maintaining healthy blood pressure and heart function.

Vitamin A plays a crucial role in maintaining healthy vision, skin, and immune system function. Vitamin C is a powerful antioxidant that helps protect cells from damage, supports immune system function, and aids in collagen synthesis for healthy skin, tendons, and ligaments. Beta-carotene is converted to vitamin A in the body and is important for maintaining healthy skin and vision. Folate is a B vitamin that is essential for healthy foetal development during pregnancy and helps to produce red blood cells. In addition to these essential vitamins and minerals, baobab leaves also contain a relatively high amount of fibre which aids in digestion and can promote a feeling of fullness.

(National Academies of Sciences, 2006).

 

Table 1: Proximate nutritional composition of 100 g of Baobab leaves

 

Source (Nutrient data): FAO/Government of Kenya. 2018. West African food composition table, https://www.fao.org/3/ca7779b/CA7779B.PDF 

$ Draining the water several times leaches away water soluble nutrients significantly.
a Lewis, J. 2019. Codex nutrient reference values. Rome. FAO and WHO
b NHS (refers to saturated fat)
c https://www.hsph.harvard.edu/nutritionsource/water/
d British Heart Foundation
e FDA
f NIH
g Mayo Clinic

 

Complimentary recipes

 

1. Baobab and Cassava vegetable

Mijikenda in coast Kenya recipe

Ingredients for Baobab/ Mpea dish (serves 6 people)

• One handful of tender Baobab leaves (Tender leaves picked from young Baobab shoots)
• Three handfuls of pounded Mpea (Cassava leaves). Tender leaves from cassava shoots.
• Two medium-sized Coconuts (if the coconut is fleshy, as is the case during the rainy season, a coconut is enough.)
• ½ teaspoonful of salt
• 3 cups of water

Cooking procedure

• Sort Baobab and cassava leaves
• The Cassava leaves are pounded in a mortar before cooking to improve palatability.
• Boil pounded cassava leaves in a pot for 3-4 minutes on high heat
• Add Baobab leaves to the pot and boil for 3 minutes.
• Prepare the Coconut Milk by mixing 1/2 a cup of water and grated coconut flesh. The mixture is squeezed tightly in the hands or strained through a fine cloth to wring all liquid from the coconut flesh.
• Add the Coconut milk and salt to the boiling vegetable mixture and boil for another 2 minutes

 

 

2. Miyan Kuka (Baobab leaves soup)

Traditional Nigerian soup

Ingredients

• 500g meat with bone or meat alternatives (veal, lamb, beef, chicken or Tofu)
• 4 tbsp ground baobab leaves (22g)
• 1 onion
• 1 tomato
• 3 garlic cloves
• 2 bay leaves
• 1 tbsp of ground soumbala (also called dawadawa is a fermented seed condiment in West Africa)
• 1 tsp dried shrimps
• 3 cups of water
• 1 hot pepper
• Salt and black pepper to taste
• Oil

Cooking procedure

• Chop onions and garlic. Cut meat into pieces
• Add 2 tablespoon full of oil into a pot, and adjust heat to medium- high
• Add meat and onions to oil, and sauté for about 2-3 minutes until both meat turn brown. Add tomatoes, garlic bay leaves and 3 cups of water
• Scrape the bottom of the pan with a wooden spoon if any residue are stuck
• Take care to have the meat covered with water. Add about ¼ tsp of salt
• Partly cover stew and cook for about an hour. Add soumbala and dried shrimp. Cook for 20 more minutes. Meat should be tender
• Add baobab leaf powder, about 1 tbsp at a time and mix after each addition to incorporate the powder
• Let simmer for about 10 more minutes

 

Source:

 

3. Fried Baobab leaves

Ingredients (yields 4 servings) I bunch (100 g) of tender Baobab leaves Onions (50 g) 2 tablespoonful cooking oil Tomatoes (80 g) 1 Cup  water Seasoning (optional)
Cooking procedure Chop the Baobab leaves Bring water to boil, add vegetables and boil for 3 minutes. (You may blanch the vegetable instead of boiling) Heat oil, add the diced onions and fry them lightly Add the vegetables and stir for a minute Add the diced tomatoes and cook for 2 minutes Add salt to taste then stir Serve with a starchy source e.g. ugali Serve with preferred starch and stew