The potential of pigeonpea
A legume that has been revolutionized in recent years is pigeonpea (Cajanus cajan). For years it was looked on only as a poor man's
crop - useful only in very dry areas where farmers can only scratch a living. But now plant breeders have transformed this subsistence crop of
the semi-arid tropics into a versatile and high-yielding crop that is resistant to disease and can be
grown in high and low rainfall areas. For rural people pigeonpea provides food, fuel, forage and - as a legume - enhances soil fertility.
Furthermore, it is exported as a whole range of products providing extensive benefits for smallholder farmers and
consumers.
The majority of pigeonpea production is in India (~85%) but the distribution of the crop is global and it is an important source of protein for over a billion people. An ICRISAT study located pigeonpea, which is prepared and consumed in a wide variety of forms, in 37 African countries and across most of Central and South America and the Caribbean. The innovative research carried out by ICRISAT in partnership with a number of collaborating organizations over the last twenty-five years has therefore had a significant impact far beyond India. Through their continuing efforts, ICRISAT scientists hope to expand the production of pigeonpea into new areas (see In Print 'Pigeonpea in Sri Lanka') as an affordable alternative to meat-based protein.
Disease resistance
Collections of pigeonpea landraces and wild species from 72 countries have provided extensive germplasm for breeders to incorporate new traits into breeding populations. Genetic studies of this material have not only revealed resistances to pests and disease but has also enabled scientists to determine Asia as the centre of origin for pigeonpea. ICRISAT's first major impact in disease resistance was to release a Fusarium wilt resistant line in India in 1986. Known as 'Maruthi' (name of a Hindu hero), the variety has been widely adopted and its resistance has remained durable and its success resulted in the establishment of resistance germplasm and wilt screening methodology for the Pigeonpea Improvement Project for Eastern and Southern Africa. Newly developed resistant varieties yield far higher than traditional varieties and adoption of these in Malawi alone, where Fusarium wilt is a particular problem, would enable farmers to produce extra grain worth US$ 2 million every year.
A wide variation
Further impact has been achieved by ICRISAT and partner organizations in the productivity of pigeonpea. Traditional varieties are tall, take 6-10
months to mature and are usually grown as an intercrop with cereals such as sorghum, millet and maize. But through the breeding efforts of pigeonpea
scientists short-duration varieties, which mature in under four months and on less than 200mm of rainfall, can be grown as a monocrop.
These varieties are shorter and more compact, are usually resistant to drought, frost and disease, and provide
higher yields. The short maturation of the crop also means that farmers can still sow their post-rainy cereal crop.
There are now four distinct durations for pigeonpea varieties - extra short (mature in <100 days), short (100-120 days), medium (140-180) days and long duration (>200 days). Each group is suited to a particular agro-ecosystem, which is defined by altitude, climatic temperatures, latitude and daylength. Over the last five years 21 improved varieties have been developed for Africa, of which two have been released in Kenya and one in Malawi and another is shortly to be released in Uganda, Kenya, Malawi and Tanzania. In Asia, the potential for the extra short varieties is being explored for growing within the rice-wheat systems of the Indo-Gangetic Plains. This high-input system, which has begun to show signs of instability, could become more sustainable with the inclusion of pigeonpea into the rotation by providing farmers with an alternative to rice during periods of water shortages, price incentives and problems of soil fertility.
Improved production packages are also being developed to help farmers improve their cropping systems and harvested yields. One recommendation for intercropping involves planting paired rows of medium and long duration pigeonpea combined with three rows of maize. In on-farm trials in Kenya and Tanzania, this system increased pigeonpea yields by 55% with no accompanying decline in maize production and no increase in labour. Optimal spacings for short duration pigeonpea are also being developed for Kenya, Tanzania and Uganda.
Possibilities for export
Farmers, including women who are involved in post-harvest processing and marketing, are also recognizing the versatility of short duration pigeonpea for green pea production. Immature (green) pigeonpea is consumed fresh as a vegetable in many regions where it attracts high prices and delivers a crop more quickly than dried peas. The short duration varieties are relatively photo-insensitive so, if irrigated, can be sown at different times of the year to reap higher off-season prices for fresh produce. If pods are removed continuously, several crops can be harvested from the same plant. Alternatively, the whole grain can be harvested, frozen or dried for split peas, for export to North America and Europe. Demand is such that a full-scale production scheme has been established with Kenyan smallholder farmers for export of fresh and frozen green pigeonpeas to the UK.
