Functional Characterization of Water Saving Traits to Enhance Drought Adaptation in Sorghum

Sorghum (Sorghum bicolor [L.] Moench), a key staple in South Asia and sub-Saharan Africa, is increasingly challenged by climate variability. In India, post-rainy sorghum remains a vital food and fodder crop. In alignment with the ICRISAT post-rainy sorghum product profile, this study characterized sorghum parental lines for key traits associated with drought adaptation in pot using the dry-down experiment. The atmospheric drought experiments revealed significant genotypic variation in transpiration rate (TR) under high vapor pressure deficit (VPD), with K359W showing restricted TR and R16 exhibiting high TR. In soil drought trials, transpiration decline began at an FTSW of 0.49 in K359W and 0.56 in R16. K359W consistently outperformed R16 in plant growth, water use, biomass, and showed higher transpiration efficiency (TE). Genotypes with greater vigor, reduced TR under high VPD, and higher TE offer strong potential for improving post-rainy sorghum drought resilience.