Genetic Divergence in Sorghum [Sorghum bicolor (L.) Moench] Genotypes under Contrasting Moisture Environments

Sorghum is one of the most important cereal crops in Ethiopia which is grown most dominantly in the low land area where drought predominates. In this area farmer’s preference to improved sorghum variety is dependent on earliness and drought tolerance traits. The objective of the study was to evaluate the genetic diversity of early maturing sorghum genotypes for drought tolerance by using principal component and cluster analysis. Twenty three early maturing sorghum genotypes were phenotyped under post-flowering moisture stressed and non-stressed environment using RCBD design in adjacent experiment. The analysis of variance revealed significant variation among genotypes for most of the traits for both moisture environments. Post-flowering drought reduce the value for all of the traits except flag leaf area and average grain yield was reduced by 21%. Five genetically divergent clusters which showed significant inter cluster distance were observed in both environments. Genotypes in cluster one showed best performance for grain yield and yield components under non-stress environment. Under stressed environment, genotypes under C1, and C2 revealed best performance for drought tolerance and yield traits, respectively. Therefore, the performance of genotypes under these clusters and different clustering pattern observed depicts the divergence of genotypes for drought response which creates opportunity for further improvement through selection and hybridization. Principal component analysis revealed five and seven PC captured 80% and 87% of total variation observed under stressed and non-stressed environment, respectively.