ADAPTABILITY OF COWPEA (Vigna unguiculata) LINES IN COASTAL REGION OF KENYA

Abstract

Cowpea (Vigna unguiculata L. Walp.) is one of the most important grain legumes grown in sub-Saharan Africa. About 12.5 million tonnes of cowpea grain are produced worldwide each year with the majority (over 94%) of the production taking place on low input, subsistence farms. This crop is most important in the semi-arid and warm areas of Africa where other crops may fail due to poor adaptation to heat, drought and low soil fertility conditions. This study aimed at developing high yielding, drought tolerant and farmer acceptable cowpea genotypes in coastal Kenya to contribute to increased food production.. The experiment was conducted Kenya Agricultural and Livestock Research Organization (KALRO), Mtwapa and replicated in its sub-centres at Msabaha and Mariakani in coastal lowlands of Kenya. Fifteen cowpea genotypes were sourced from the KALRO Gene bank which included three improved cultivars that have been tested in central and eastern regions of Kenya. The lines included; K033057, K033073, K003731, K005169, K026753, K027092, K003962, K046781, K028613, K047079, K047078, K047121, KVU 27-1, M 66 and with K 80 and local variety (Mnyeza) as the checks Planting was done at a spacing of 60 cm × 30 cm, the trial was laid out in a randomized complete block design (RCBD) with three replications and planting was done during the short and long rain season of 2012 and 2013 respectively. After harvesting pod weight, grain yield, 100 seed weight was determined in different lines. The year effects were clearly manifested in the agronomic traits and seed quality of the cowpea genotypes evaluated. K005169 was superior in grain yield in all the agroecological zones making it a candidate for consideration in the breeding with others to introgress the genes for high yield potential. The 16 genotypes attained maturity within 70 to 76 days after planting and were therefore classified as early maturing types. Of the 16 genotypes tested five (K005169, KVU 27-1, M66, K003962 and K046781) showed outstanding performance across the test environments. The genotypes manifested their adaptability and stability across test environments and were recommended for introduction in the region to contribute to increased cowpea production.