Mapping genetic gains: Broad-Sense heritability and trait variability in sorghum [Sorghum bicolor (L.) Moench] at Arba Minch, South Ethiopia

Genetic variation is vital for the plant breeding program. Eighty-one sorghum genotypes were tested in a simple lattice design at Arba Minch Agricultural Research Center in the 2020and 2021main cropping seasons with the objectives of assessing variability, heritability and genetic advance as a percent of the mean and genetic advance. The analysis of variance revealed that there were statistically significant differences among the genotypes for most of the studied traits. In terms of mean value performance, the genotypes showed noticeable variability in grain yield ranging from 95.6kg/ha to 7793.3kg/ha. The higher range of genotypic coefficient of variation values (GCV) (9.2–39.0) and phenotypic coefficient of variation (PCV) (11.5–39.4) were perceived. Relatively high phenotypic coefficient of variation (PCV) values (>20%) were attained for head length, head diameter, plant height, and grain yield. Similarly, high genotypic coefficient of variation (GCV) values (>20%) were also obtained for head length, height, and grain yield. The higher heritability estimates (> 80%) were realized for plant height and grain yield. Grain yield (GY) (98.20%) and head diameters (HD) (3.40%) were the highest and lowest broad sense heritable (H²) traits, respectively. The traits with the highest estimates of genotypic coefficient of variation, genetic progress as a percentage of the mean, and broad-sense heritability were GY (98.2%), plant height (81.4%), head length (78.5), days to 90% maturity (66.3) and days to 75% flowering (63.8). Because of their advanced heritable characteristics and high estimates of the genotypic coefficient of variation and genetic advance as a percentage of total genetic variation, these qualities are useful for selective breeding. Therefore, hybridization and selection of these genotypes for desired traits with high H² together with higher GCV and GAM (genetic advance as a percent of the mean) will be effective in developing superior sorghum cultivars. Further improvement of these genotypes for desired traits is an important criterion for the sorghum improvement program.