2019 ASHS Annual Conference

Cowpea is a legume species that can better withstand drought conditions compared to other legumes, so it can be used as a model crop to enhance our understanding of drought tolerance. Witling status and leaf chlorosis have been previously demonstrated to be a good indicator of drought tolerance in cowpea at early vegetative stage. Being provided with these phenotypic information would help cowpea breeders improve elite genotype being deficient in drought tolerance trait and scientists better understand the mechanism underlying drought tolerance. Therefore, this study aimed at evaluating a total of 331 cowpea genotypes for wilting status, leaf-related traits, and plant greenness score under drought stress at early vegetative stage. A total of 331 cowpea genotypes were evaluated for drought tolerance in a greenhouse using a Randomized Complete Block Design (RCBD) with 3 blocks. A tolerant control (PI293568) and a susceptible control (PI255774) as previously reported were used to validate the experiments. Data on plant greenness score, wilting status, plants showing chlorotic unifoliate leaves, chlorotic first trifoliate leaves, ratio between chlorotic trifoliate leaves and green trifoliate leaves, and plants displaying dead growing point were recorded. Data will be analyzed using ANOVA in SAS v. 9.4 and mean separation will be done using a protected LSD at α=0.05. The preliminary results showed a large variation in those traits among the 331 cowpea accessions. Weak to strong Pearson’s correlation coefficients were identified among the traits. These findings can be applied in cowpea breeding programs to improve tolerance to water deficit conditions.