Physiological parameters governing drought tolerance in maize

Sixty diverse genotypes of maize comprising of inbreds, hybrids and composites were evaluated under drought environments for different physiological parameters viz. chlorophyll stability index, stomatal diffusive resistance, leaf temperature and transpiration rate. Results revealed that flowering and grain filling were the critical growth stages, at which the drought had the maximum adverse effects. Under severe stress, the anthesis-silking-interval range for resistant and susceptible genotypes was 3–5 and 9–17 days, respectively. Chlorophyll stability index decreased with increasing water stress in most of the genotypes. Tolerant lines showed less leaf temperature under stress but transpiration rate was comparatively high. The drought tolerant inbreds and hybrids identified for various physiological traits were HI-209, 295, 536, 1040 (inbreds), 536 × 295, 552 × 645, 1035 × 645, 1027 × 745 (hybrids). These lines can be used in the future breeding for developing drought tolerant maize genotypes.