Narrow genetic base, information on the genetic variation, early maturing and drought tolerant sorghum genotypes are the most important limiting factors for sorghum yield improvement under moisture stress areas. Therefore, the experiment was conducted to quantify the genetic variation available among sorghum genotypes for drought tolerance related traits. A total of 42 sorghum genotypes were evaluated using alpha lattice experimental design with two replications at Mieso and Kobo during the main cropping season of 2019. The combined analyses of variance revealed the presence of substantial genetic variation among sorghum genotypes for all the studied traits over locations. Among the traits with high genotypic coefficient of variation and heritability estimate, plant height, panicle exersion and panicle yield were linked with higher values of genetic advance as percentage of mean, reflecting the variability of these traits is controlled by additive gene action and environmental influence is less in phenotypic expression. The high heritability and genetic advance as percent of mean were obtained for plant height (95.63 and 45.39%), 100 seed weight (77.98 and 23.86%), panicle exertion (74.87 and 51.88%), and panicle yield (65.43 and 37.32%) in the same order. The maximum grain yield was obtained from a hybrid 4x14 (6.32 tha-1) followed by hybrid 8x15(5.92 tha-1), 1x15 (5.88 tha-1), 13x14 (5.78 tha-1) and 6x15 (5.57 tha-1) with the average value of 5.00 tha-1 which had higher mean value than the mean of the parents and the check (Melkam). Hence hybrids have been found to be better suited than their parents and open pollinated variety to drought stress environments as a result of earliness, better adaptation and yield performance. In general, this study showed the existence of genetic variability in sorghum genotypes for different traits grown under moisture stress condition, providing opportunity to select several promising genotypes with key traits related to drought tolerance. In conclusion, plant height, 100 seed weight, panicle exertion, and panicle yield could be improved through simple selection. The sorghum genotypes showed substantial genetic variation for studied traits under drought stress condition and could be utilized by sorghum breeders to develop new and economically important sorghum varieties.
Keywords: Genotypic co-efficient of variation; Phenotypic co-efficient of variation; Drought; Broad-sense heritability; Genetic gain as percent of mean