Physiological and biochemical characteristics of glossy/non-glossy sorghums developed under three stress factors

Five selected genotypes (three resistant and two susceptible) were evaluated under combined conditions of drought, salinity and high temperature. CO2 assimilation rate, transpiration and water use efficiency were the variables considered. High genetic variability was found among genotypes. IS-22201, IS-4473 and IS-8311 (resistant) showed a small difference in CO2 assimilation and transpiration between stress treatment and control, while IS-5484 and IS-1096 (susceptible) showed larger differences. Proline in roots, HCN, chlorophyll and epicuticular wax in leaves were evaluated. IS-22201 and IS-4473, showed increase in proline and HCN under stress conditions, while in IS-5484 and IS-1096, there was no change in these compounds. Chlorophyll decreased under stress in resistant genotypes; in susceptible ones no significant change was observed. Physiological and biochemical adaptations permit resistant sorghum genotypes to be productive in environments affected by several stress factors.