Breeding High Yielding Cowpea Varieties with Improved Seed Quality and Enhanced Nutritional and Health Factors.

Cowpea [Vigna unguiculata (L.) Walp.] is a major source of dietary protein, vitamins, minerals and health promoting factors in the tropics and sub-tropics. It is consumed in a many ways using its tender leaves, immature pods and fresh seeds as vegetable and dry seeds for various culinary preparations.  However, the cultivars differ from region to region based on the regional preferences for seed size, seed color, seed eye pattern and seed coat texture.  Therefore, the early focus in the cowpea breeding programs was to breed for high yield with acceptable seed characteristics. With support from the HarvestPlus Bio-fortification program of CGIAR, a systematic improvement program for enhanced nutritional and health traits was initiated in 2003. Subsequent breeding efforts have resulted in the development of high yielding cowpea varieties with over 30% protein, 70 ppm iron, 45 ppm zinc, 858 ppm calcium, 14378 ppm potassium, 1987 ppm magnesium and much higher levels of antioxidants. Interesting relationships were observed between physical and nutritional properties of different seed types. The range in protein content was similar in all seed types but smooth seeds had higher seed coat content and thus richer in fiber content compared to the rough seeds; larger seeds took longer time to cook compared to smaller seeds; and colored seeds like black, red and brown  had 4-5 times more antioxidant activity compared to the white, green and cream colored seeds. Also, colored seeds germinated better than white seeds if it rained immediately after planting probably due to their antifungal and antibacterial properties.