Characterization of cowpea genotypes for traits related to early-season drought tolerance

Authors: POUDEL, SUJAN - Mississippi State University; SANKARAPILLAI, LEKSHMY - Mississippi State University; SIVARATHRI, BALA - Mississippi State University; HOSAHALLI, VIJAYKUMAR - Mississippi State University; HARKESS, RICHARD - Mississippi State University; BHEEMANAHALLI, RAJU - Mississippi State University

Submitted to: Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2025
Publication Date: 5/16/2025
Citation: Poudel, S., Sankarapillai, L.V., Sivarathri, B.S., Hosahalli, V., Harkess, R.L., Bheemanahalli, R. 2025. Characterization of cowpea genotypes for traits related to early-season drought tolerance. Agriculture. 15(10)1075:1-21. https://doi.org/10.3390/agriculture15101075.
DOI: https://doi.org/10.3390/agriculture15101075

Interpretive Summary: Cowpea is an important legume crop valued for its nutrition and adaptability, but drought stress during early growth stages can adversely affect its growth and yield. Identifying drought-tolerant cowpea genotypes is crucial for maintaining yield potential. A study characterized 15 cowpea genotypes for physiological, pigment, and morphological traits linked to drought tolerance under two moisture regimes (100% irrigation and 50% irrigation) for 22 days. Drought-stressed plants showed a 79% decrease in stomatal conductance and a 2.9 °C increase in canopy temperature. Key findings included a 51% decrease in shoot biomass and a 32% decrease in root biomass under drought conditions, with leaf area and shoot weight correlating with root traits. Among the genotypes, those that exhibited superior rooting vigor under drought conditions were identified. The study highlights the potential for using drought-adaptive traits in cowpea breeding programs to enhance drought tolerance.

Technical Abstract: Cowpea (Vigna unguiculata (L.) Walp.) is a vital legume crop recognized for its nutritional value and adaptability to various growing conditions. However, exposure of cowpea to drought stress during the early growth stages can significantly restrict growth and yield potential. Therefore, identifying cowpea genotypes tolerant to drought during early growth and development is essential for maintaining yield potential. This study charac-terized 15 diverse cowpea genotypes for various physiological, pigment, and morphologi-cal traits that may contribute to drought tolerance. At the V2 stage, the cowpea genotypes were subjected to two moisture regimes: control (100% irrigation) and drought (50% irriga-tion) for 22 days to assess trait responses and their relationship to drought tolerance. Drought-stressed plants decreased stomatal conductance by 79%, negatively correlating with a 2.9 °C increase in canopy temperature. The photochemical reflectance index (PRI) was strongly associated with the quantum yield of PSII and electron transport rate under drought. Under drought, shoot biomass decreased by 51% and root biomass by 32%. Leaf area and shoot weight were correlated with root traits such as total length, surface area, and weight. Among all genotypes, 280785-11 and UCR 1004 demonstrated superior root-ing vigor under drought, emphasizing their efficiency in resource utilization. These find-ings highlight the potential to utilize drought-adaptive traits for selecting superior geno-types in cowpea breeding programs to improve stage-specific drought tolerance.