Screening of Cowpea Lines for Drought Tolerance

Abstract

Drought is a major abiotic factor that reduces cowpea yield significantly. There is need to identify true drought tolerant cowpea genotypes to aid the breeding process. The aim of the study was to screen and identify drought tolerance genotypes of cowpea. A total of 39 cowpea lines were planted in triplicates and the seedlings were watered daily for two weeks until partial emergence of the first trifoliate leaves of all varieties was observed. Thereafter, watering was stopped for 35 days and wilted plants in each variety were scored. Watering was then resumed for another 14 days to ascertain regeneration potentials of each variety. Significant differences (p < 0.05) were observed among the cowpea lines for drought tolerance. Stress effect was first observed on the unifoliate leaves 12 days after watering was stopped, followed by the emerging trifoliates as well as the drying of the growing tip. Wilting percentage at different days indicated TVx 3236 (92%), NG/SA/07/132 (100%) and IT95K-193-12 (83%) to be the most susceptible to drought. The recovery percentage after watering ranged from 0% for NG/SA/01/09/004 to 100 % for IT81D-994 and Oloyin. Based on the findings from this study, group 1 comprising three lines (TVx 3236, NG/SA/07/130 and NG/SA/01/09/004) were found to be highly drought susceptible while Group 2 and 3 comprising of 14 and 22 lines respectively were tolerant at varying degrees. The current study provides information on cowpea lines that can be recommended in breeding for drought tolerant varieties.