cowpea - final

8/3/2019 Cowpea - Final

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LIWANAG, IRISH D.AGRONOMY 152-T 1L

A GENETICRESOURCES:STATUS,PROBLEMS,

ANDPROSPECTS



•Cowpea•Vigna unguiculata

L. Walp

•Paayap•Considered to haveoriginated in Africa

•Widely grown inafrica, latin America,Southeast Asia,

Southern UnitedStates

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•Order: Fabales

•Family: Fabaceae

•Genus :Vigna

•Species: unguiculata

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Four cultivated subspecies arerecognised:

1. Vigna unguiculata subsp. cylindrica Catjang2. Vigna unguiculata subsp. dekindtiana AfricanCowpea

3. Vigna unguiculata subsp. sesquipedalis Yardlongbean

4. Vigna unguiculata

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BIOLOGY

Warm-season annual legumeLeaf is somewhat shiny and flower

color is either purple, white or yellowSeed color is diverse, ranging fromwhite, black, brown, purple to

various types of mottled seedPod length is from 20 to 30cmPod attaches sideward or downwardto the peduncle.Length of seed is 6 to 10mm

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Uses

Weed control•grows quickly and will shade

and smotherWeeds•may outcompete them for

soil moisture andnutrients

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Attract beneficialinsects•extrafloral nectaries onpetioles and leaflets;

− nourishes beneficial

insects such ashoneybees,

lady beetles,

predatory wasps, ants,-

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Feed and Food

when grown to maturity can be

used as a feed (grazedor harvested for fodder), or itspods can be harvestedand eaten as a vegetable

seed is valued as a nutritionalsupplement to cereals and anextender of animal proteins.

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Protein 24.8%

Fat 1.9%

Fiber 6.3%Carbohydrate 63.6%

Thiamine 0.00074%

Riboflavin 0.00042%Niacin 0.00281%

Table 1. Nutrient content of mature cowpea

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Germplasm diversity

• IITA holds the largestcowpea germplasm

collection− 15,115 accessionswere collected all

over the world− 10, 814 werecollected from Africa

alone

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Germplasm

diversity

•Improved varieties in 63

countries−some of which have beengiven popular local namessuch as ‘Vijaya’ (victory) and

‘Varuni’ (breeze) in Sri Lanka;‘Akash’ (sky) and Prakash(light) in Nepal; ‘Big Buff’ in

Australia; ‘Fahari’ (hope) and

‘Tumaini’ (pride) in Tanzania;

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Germplasm diversity

Various tools arecurrently used to

analyze Vignadiversity:

• Isozymes forwild Vigna• SSR for primary

gene pool

• SNP for

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Extent of Genetic

Erosion

•diseases,insect pests,nematodes,

and parasitic

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Extent of Genetic

Erosion Every stage inthe life cycle ofcowpea has at

least one majorinsect pest.

•Aphids (Aphiscraccivora)attack cowpea

especially in the

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Extent of Genetic

Erosion• flower thrips(Megalurothrips

sjostedti) at flowering,pod borer (Marucavitrata) at flowering and

pod formation,

•a complex of pod-sucking bugs atpodding, and the weevil

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Extent of Genetic

Erosion

Cowpea issusceptible toseveral fungal,

bacterial, and viral

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•Cercospora leaf spot,• ashy stem blight,•bacterial blight,•blackeye cowpea mosaic

potyvirus (BICMV),•cowpea aphid-bornemosaic potyvirus (CABMV),•and cowpea mosaic

comovirus (CPMV).• Cowpea plants are alsoattacked by the parasiticflowering plants Striga

gesnerioides and Alectra

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GERMPLASM CONSERVATION

IITA’s Genetic Resources Center (GRC) 28,000 accessions

Over 50% of the collection is made of cowpea collected from 89countries, mainly in Africa, and other Vigna spp. It is also the mostshared, with 54 of all the germplasm materials being distributed.

IITA maintains a collection of about 15,000 accessions of cultivated

cowpea and 1,500 accessions of wild cowpea relatives in its genebank.

cowpea is maintained in two storage conditions, medium (5°C) andlong-term (-20°C) at an optimal water content of 7−8% fresh weight

basis. The viability of most accessions stored at –20°C for 25 yearsremains as hi h as 90%.

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US$358,143 and$28,217 was spent

annually on theconservation andmanagement of cowpea

and wild Vigna.

Each accession costabout $72 for cowpeaand only about half ofthat for wild Vigna

Seed health testing

PEA PROBLEMS IN

GERMPLASMCONSERVATION

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estimated the annualworld cowpea crop at

12.5 million ha,

the total grain

production at 3 million t

64% of the estimated 3million t of cowpea seed

roduced annuall

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PEA ECONOMICALAND POLITICALASPECTS OF

CROPGERMPLASM

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One way to reduce these costsis by increasing the number ofaccessions, thus lowering theunit cost. Also, upgrading andexpanding the current

infrastructure to improve theefficiency of the genebank wererecommended.

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PEA RECOMMENDATION

cowpea - final

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