Evaluation of morpho-physiological characters in sorghum (Sorghum bicolor (l.) Moench) genotypes under post-flowering drought stress

Post-flowering drought adaptation in sorghum is associated with the stay-green phenotype. Plants with stay green resist droughtinduced premature plant senescence. Sorghum varietal improvement for drought conditions could be achieved more efficiently if the trait associated with drought resistance could be identified and utilized as selection criteria. Hence, field studies were carried out in a randomized block design with two replications during the post-rainy season to evaluate responses among 100 sorghum genotypes under post-flowering drought stress which include B35 and CO26 as a drought resistant and susceptible check respectively. A total of 15 morpho-physiological characters putatively related with crop performance under drought were studied. Significant variations were found in all the traits among the sorghum genotypes studied. Based on the per se performance the genotypes MS73, CO21, CO22, Tenkasi1, AS2059, AS5078, AS2752, AS5057, AS4289, MS7819, IS5379, AS8038, AS6616, K3, MS7837, Murungapatti local, Uppam chloam, VS1564, VS1560, CO24 and CO1 exhibited high mean values for relative water content, SPAD chlorophyll reading, root length, root volume, root dry weight, 1000 grain weight, grain yield, and lower score for stay-green when compared to other genotypes under stress. These genotypes also recorded low drought susceptibility index, high relative yield, stress tolerance index and yield stability ratio and they can be used as the parents for future breeding programmes.