Investigation on various above-ground traits to identify drought tolerance in cowpea seedlings

Authors: RAVELOMBOLA, WALTRAM - University Of Arkansas; SHI, AINONG - University Of Arkansas; QIN, JUN - University Of Arkansas; WENG, YUEJIN - University Of Arkansas; BHATTARAI, GEHENDRA - University Of Arkansas; ZIA, BAZGHA - University Of Arkansas; ZHOU, WEI - University Of Arkansas; Mou, Beiquan

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2018
Publication Date: 12/27/2018
Citation: Ravelombola, W., Shi, A., Qin, J., Weng, Y., Bhattarai, G., Zia, B., Zhou, W., Mou, B. 2018. Investigation on various above-ground traits to identify drought tolerance in cowpea seedlings. HortScience. 53(12):1757-1765. https://doi.org/10.21273/HORTSCI13278-18.
DOI: https://doi.org/10.21273/HORTSCI13278-18

Interpretive Summary: Drought has been described as the effects of a sustained lack of soil moisture required for plants to properly grow and produce sufficient crop yields. Long period of drought conditions reduce plant growth and development, and in extreme cases result in plant death. As a result, impacts of drought stress on crop production can significantly impair farmer’s revenue, hence adversely affecting the gross national product growth. For cowpea [Vigna unguiculata (L.) Walp.], which is a legume of economic importance, effects of drought at early vegetative growth stages could lead to substantial yield losses. However, little has been done with respect to breeding for cowpea cultivars that can withstand drought during early vegetative growth period. In addition, previous investigations have been focusing on how plant morphology and root architecture can confer drought tolerance in cowpea, which is not sufficient in efforts to unraveling unknown drought tolerance-related genetic mechanisms, potentially of great importance in breeding, and pertaining to neither plant morphology nor root architecture. Therefore, the objective of this study was to evaluate above-ground drought-related traits of cowpea varieties at the seedling stage. A total of 30 cowpea varieties were grown in boxes in a greenhouse and the experiment had 3 replications. Drought stress was imposed for 28 days. Data on a total of 17 above-ground related traits were collected. Results showed that: 1) Significant variations in these traits were found among the varieties; 2) Most varieties were more tolerant to trifoliate leaf wilting/chlorosis than unifoliate leaf wilting/chlorosis; 3) Delayed senescence was related to the ability to maintain a balanced chlorophyll content in both unifoliate and trifoliate leaves; and 4) The varieties PI293469, PI349674, and PI293568 were found to be slow-wilting and drought-tolerant. These results could contribute to the breeding efforts for drought tolerance in cowpea.

Technical Abstract: Impacts of drought stress on crop production can significantly impair farmer’s revenue, hence adversely affecting the gross national product growth. For cowpea [Vigna unguiculata (L.) Walp.], which is a legume of economic importance, effects of drought at early vegetative growth stages could lead to substantial yield losses. However, little has been done with respect to breeding for cowpea cultivars that can withstand drought during early vegetative growth period. In addition, previous investigations have been focusing on how plant morphology and root architecture can confer drought tolerance in cowpea, which is not sufficient in efforts to unraveling unknown drought tolerance-related genetic mechanisms, potentially of great importance in breeding, and pertaining to neither plant morphology nor root architecture. Therefore, the objective of this study was to evaluate above-ground drought-related traits of cowpea genotypes at the seedling stage. A total of 30 cowpea genotypes were grown in boxes in a greenhouse and the experiment had a completely randomized design with 3 replications. Drought stress was imposed for 28 days. Data on a total of 17 above-ground related traits were collected. Results showed that: 1) Significant variations in these traits were found among the genotypes; 2) Most of the genotypes were more tolerant to trifoliate leaf wilting/chlorosis than unifoliate leaf wilting/chlorosis; 3) Delayed senescence was related to the ability of maintaining a balanced chlorophyll content in both unifoliate and trifoliate leaves; and 4) The genotypes PI293469, PI349674, and PI293568 were found to be slow-wilting and drought-tolerant. These results could contribute to the breeding efforts for drought tolerance in cowpea.