Evaluation of Cowpea Varieties for Drought Tolerance in Katsina State

This study evaluates cowpea varieties for drought tolerance under the semi-arid conditions of Katsina State, North West Nigeria. Cowpea is the most important grain legume in northern Nigeria, providing dietary protein for millions of households, but recurrent drought stress during the short rainy season significantly reduces yields. Identifying drought-tolerant varieties that maintain yield under water stress is essential for food security in this climate-vulnerable zone. This study evaluates eight cowpea varieties: IT97K-499-35, IT90K-277-2, SAMPEA 7, SAMPEA 11, SAMPEA 14, IT89KD-391, Dan Gero (local), and IT85F-2687 under two irrigation treatments: well-watered and terminal drought stress imposed at flowering in a split-plot design at Umaru Musa Yaradua University Katsina research farm. Leaf water potential, relative water content, chlorophyll content, days to maturity, number of pods per plant, and grain yield under each water regime are measured. Drought tolerance indices including stress susceptibility index and yield stability index are computed. Findings reveal that SAMPEA 14 and IT90K-277-2 maintain the highest grain yields under drought stress, with yield reductions of 18 and 22 percent respectively compared to 58 percent reduction in the most drought-susceptible local variety. These varieties also show the highest relative water content under stress, indicating superior osmotic adjustment. The study concludes that SAMPEA 14 is the most drought-tolerant variety evaluated and recommends its adoption for Katsina State's rain-fed production areas.

Keywords: cowpea varieties, drought tolerance, Katsina State, yield stability, semi-arid.