Despite many years of research, drought is still a major factor affecting crop productivity globally and presents a challenge to plant breeders. Understanding the genetic variability among sorghum genotypes is key to the development of improved sorghum cultivars for drought-prone environments. A set of 72 sorghum genotypes advanced from a pedigree breeding approach was used in this study. The result showed that Grain yield varied from 2.10 t/ha to 6.32 t/ha. Genotypic and phenotypic coefficient of variation ranged from 0.56% (stay green score) to 23.88% (harvest index) and 0.66% (stay green score) to 28.99% (harvest index), respectively. Broad sense heritability ranged from 25.56% (drought tolerance score) to 86.87% (grain filling rate) while genetic advance as a percent of mean ranged from 1.11% (drought tolerance score) to 43.40% (grain filling rate). Principal component analysis (PCA) revealed that five principal components with Eigenvalue greater than unity accounted for 74.1% of the total variation. The first two PCs accounted for a cumulative 39.5% of the total variation indicating most of the important yield and yield-attributing traits were present in these first two PCs. Cluster analysis grouped the test genotypes into five clusters. Cluster I, II, III, IV, and V accounted for 41.667%, 6.944%, 26.389%, 16.667%, and 8.333% of the tested genotypes in that order. The highest intra-cluster distance was observed for cluster V whereas the maximum inter-cluster distance, to be used as a source for the hybridization program was observed between cluster IV and V. The lowest intra-cluster distance was observed for cluster III, whereas clusters I and III showed the lowest inter-cluster distance.

Keywords: Genetic Advance, Heritability, Principal Component and Cluster Analysis