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Know your Cowpea

Know your Cowpea - Introduction

  • The Cowpea (Vigna unguiculata), aka Field Pea, is one of several species of the widely cultivated genus Vigna
  • Four cultivated subspecies are recognised:
    1. Vigna unguiculata subsp. cylindrica Catjang
    2. Vigna unguiculata subsp. dekindtiana African Cowpea
    3. Vigna unguiculata subsp. sesquipedalis Yardlong bean
    4. Vigna unguiculata subsp. unguiculata Black-eyed pea
  • Cowpeas are one of the most important food legume crops in the semi-arid tropics covering Asia, Africa, southern Europe and Central and South America. 

Know your Cowpea - Common names

  • Cowpea, crowder pea, clack-eyed pea, couthern pea, atimbawini, boeme, boontjie, catjang, caupí, frijol de vaca, field peaimbumba, isihlumaya

  • A subcategory of field peas is crowder peas, so called because they are crowded together in their pods, causing them to have squarish ends.

Know your Cowpea - Botany

  • It is a herbaceous, prostrate, climbing, or sub-erect to erect legume, growing 15-80 cm high. 
  • Erect and bushy to prostrate and creeping growth habits exist depending on cultivar and growing conditions. 
  • Cowpeas develop strong root systems that have many spreading laterals in the surface soil. 
  • The stems have circular sections and are pock marked. They are sometimes slightly grooved and are glabrous. The texture is fibrous and hard, firm and not inflated when young. 
  • Leaves are alternate and trifoliolate and the leaflets are oval, pointed (6-15 cm x 4-11 cm). They are generally entire and sometimes lobed. 
  • Genotypes vary in the degree of pubescence, but all cultivated cowpeas are less glabrous than other legumes such as common bean and soybean. 
  • Stipules are spurred at the base, stipels are hardly visible. 
  • Inflorescence racemose, flowers white, cream, yellow, mauve or purple. 
  • Pods usually occur in pairs forming a V, and are non-dehiscent. 
  • Pod orientation is mostly pendant and vertical. 
  • Pod length ranges from 6.5-25 cm and the width ranges from 3-12 mm. 
  • Under warm conditions, pod development is rapid and may take only two weeks from pollination to pod maturation. 
  • Each pod holds from 8 to 20 seeds in a crowded orientation. 
  • Seed length is between 6-11 mm and the width is from 4-9 mm. The testa colour also varies from white, pinky-white, pink, tan, brown, and black. The hylum is often ringed black or brown, strongly contrasting with the shade of the testa and hence the name "blackeyed beans" of the Antilles. 
  • It is susceptible to frost. 
  • It is an annual. Some cowpea varieties may start flowering 30 days after sowing and are ready for harvest of dry seeds 25 days later; others may take more than 90 days to flower, and 210-240 days to mature. 

Know your Cowpea - Uses

  • Cowpea is one of the most important grain legumes in Africa and in parts of the Americas and Asia. 
  • In addition to its dry grain, fresh-shelled 'peas', fresh pods, and fresh and dried leaves and flowers are consumed in some regions. 
  • The plant is used as cut and carry forage, and for hay and silage. 
  • Cowpea forms highly effective associations with a wide range of native nitrogen fixing strains of Rhizobium bacteria and with mycorrhizae that allows the species to tolerate poor soils. 
  • Used as a green manure, it can be incorporated into the soil 8-10 weeks after sowing, and can provide the equivalent of 80 kg/ha N to a subsequent crop. 

Know your Cowpea - Origins

  • It is native of West Africa and cultivated throughout the tropics and subtropics between 40ºN and 30ºS at elevations between sea level and 2,000 metres. 
  • Occurs in areas with annual rainfall between 400-2000 mm and summer temperatures between 25-35°C. 

Know your Cowpea - Cultivation

  • Found on a wide range of very acid (pH 4) to strongly alkaline also low-fertility soils from sands to heavy, well-drained clays, with a preference for lighter soils. 
  • A drought-tolerant and warm-weather crop, cowpeas are well-adapted to the drier regions of the tropics, where other food legumes do not perform well. 
  • It does not tolerate extended flooding or salinity. 
  • Most cowpea accessions exhibit classic short-day responses with respect to time of flowering, although a range of sensitivities occur and the effect is modulated by temperature. 
  • It is mainly autogamous and in most environments out-crossing is low (less than 5%), but in the presence of bumble bees or other large insects, out-crossing can be much higher. 
  • Flowers open early in the morning, close by noon and may fall off during the same day. 
  • It also has the useful ability to fix atmospheric nitrogen through its root nodules, and it grows well in poor soils with more than 85% sand and with less than 0.2% organic matter and low levels of phosphorus. 
  • In addition, it is shade tolerant, and therefore, compatible as an inter-crop with maize, millet, sorghum, sugar-cane, and cotton. 
  • This makes cowpea an important component of traditional inter-cropping systems, especially in the complex and elegant subsistence farming systems of the dry savannah in sub-Saharan Africa. 

Know your Cowpea - Cuisine

  • Cowpeas are a common food item in the southern United States, where they are often called field peas
  • In Gujarati, these are called Chola/Chowla(ચોળા). In Marathi, these are called Chawali/Chavali(चवळी). (Kārāmani or Kārāmani Payir or Thatta Payir Tamil) are an integral part of the cuisine in southern region of India. 
  • In Tamilnadu during the Tamil month of Maasi (February) - Panguni (March) called Kozhukattai/Adai (steamed sweet cake) prepared with cooked and mashed cowpea bean mixed with jaggery, ghee and other sub ingredients. 
  • In Hindi, it is called 'Lobhia'.
  • According to the USDA food database, cowpeas have the highest percentage of calories from protein among vegetarian foods.