Grasspea

Grasspea (Lathyrus sativus) has been cultivated in Ethiopia for more than 2500 years for food and fodder. Today, the crop is grown on about 110,000 ha, producing 0.8–1.0 million tonnes annually. It is planted in rotation after barley in years when late-season rains are abundant.
     Grasspea is a very hardy, drought-tolerant crop with a deep penetrating root system. It can be grown on a wide range of soil types, including heavy clays where water-logging is common. When other crops fail, grasspea can become the principal, or only, food for the poor.
     This ability to provide economic yield under adverse conditions has made grasspea a popular crop in subsistence farming systems in many developing countries, and it has great potential for use in marginal, low-rainfall areas.
     Although grasspea seed is a tasty source of high-quality protein (often exceeding 30%), over-consumption for a prolonged period can result in paralysis of the legs (lathyrism), caused by the neurotoxin B-n-Oxalyl-L-2,3 diaminopropionic acid (B-ODAP). Farmers who grow grasspea are likely victims of this debilitating disease in years of famine, when they face the choice of starving or risking permanent paralysis. Ethiopia has suffered several lathyrism epidemics in the past 50 years. The most recent occurred in northeastern Ethiopia following the drought of 1995/96 and the subsequent widespread failure of crops. More than 2000 people in the area suffer lathyrism.
     Recognizing the importance of this crop, ICARDA and EARO scientists undertook a joint project financed by the Department for International Development, UK, to develop cultivars with low (less than 0.2%) B-ODAP, improve management strategies for safe consumption, and improve agronomic performance and yield.
     Lines with low B-ODAP and high yield potential were developed using conventional breeding methods and somaclonal variation technique at ICARDA. These were tested in Debre Zeit, Ethiopia, and several displayed excellent performance (Table 1). The Ethiopia study revealed that B-ODAP concentration in the seeds increases with reduced soil moisture. Thus, a combination of low B-ODAP lines and early sowing to avoid moisture stress can keep the neurotoxin at levels safe for human consumption.

     And there is some evidence that grasspea toxicity is related to certain soil micronutrients, notably iron and zinc. Addition of zinc in vertisols of Ethiopia, which are low in zinc and high in iron, reduces seed neurotoxin content.

Grasspea IFLLS 502, a new low-neurotoxin line, thrives in a farmer’s field in Ethiopia. This was the highest yielding of all lines tested by ICARDA and Ethiopian researchers. It had a neurotoxin level as low as 0.15%.

New low-neurotoxin grasspea lines, jointly developed by ICARDA and Ethiopian researchers, being evaluated at Debre Zeit Research Center. The performance of these lines has renewed the interest of Ethiopia in grasspea improvement research.