2019 ASHS Annual Conference

Crop losses due to salinity can cost 12 billion US dollars per year globally. Salinity has been reported to have negative impacts on cowpea [Vigna unguiculata (L.) Walp] production. These impacts are acute when salt stress occurred at seedling stage. Due to improper agriculture practices such poor irrigation quality and fertilization misapplication, cropland areas affected by salinity have kept increasing. Salinity has been shown to limit the use of cowpea as a cover crop in the western part of the U.S. Breeding for cowpea salt-tolerant cultivars would be an affordable solution to alleviate the impacts of salinity on cowpea production. Therefore, the objective of this study was to evaluate the variation in quantitative above-ground traits in cowpea genotypes under salt stress at seedling stage and to identify promising salt-tolerant cowpea genotypes. A set of 331 genetically diverse cowpea accessions were phenotyped in a greenhouse for salt tolerance using a Randomized Complete Block Design (RCBD) with 3 blocks and 2 replications within each block. Plant height, stem diameter, fresh leaf biomass, and total fresh biomass were recorded before applying the salt stress and when the susceptible control (PI255774) was completely dead. Salt tolerance index ((Non-stress – Stress)/(Non-stress)) X 100 ) and indicator of salt stress ((After Stress/Before Stress) x 100) were computed for each trait. ANOVA will be conducted using SAS v. 9.4 and mean separation will be achieved using a protected LSD procedure at α=0.05. Broad-sense heritability (H) will be computed for each trait. Our preliminary results showed a large variation in the aforementioned traits. The findings can contribute towards bettering breeding for salt-tolerant cowpea cultivars.