Morphological and Physiological Responses of Sorghum to Drought: Implications for Development of Climate-resilient Cultivars

Abstract

Drought is a significant environmental stress affecting crop productivity, particularly, in semi-arid regions where sorghum [Sorghum bicolor (L.) Moench] serves as an essential crop for food and fodder. Therefore, it is paramount to evaluate such crop varieties with potential for use in the development of climate-resilient ones through breeding and selection. A greenhouse pot experiment was carried out at Teaching and Research Farm of the School of Agriculture (A. G. Carlson Technology area), University of Cape Coast (UCC), to determine the morpho-physiological responses of seven sorghum varieties, focusing on the stay-green trait under drought-stressed (DS) and well-watered (WW) conditions. Parameters measured included green leaf area (GLA), relative water content (RWC), chlorophyll content, and grain yield. The results showed that the Dorado and Kapaala varieties exhibited greater drought resilience, maintaining higher GLA, RWC, chlorophyll levels and grain yield under drought stress conditions. Strong positive correlations between RWC, GLA, chlorophyll level, and grain yield parameters under DS highlighted these metrics as potential indicators for selecting drought-tolerant sorghum varieties. Thus, sorghum varieties such as Dorado and Kapaala could be employed in breeding programs for the development of climate-resilient varieties. The strong positive correlations between some morphological and physiological characters could be used to indirectly select for improved grain yields. This study underscores the importance of genetic diversity in crop resilience and provides valuable insights for breeding programs aimed at enhancing drought tolerance in sorghum.