Genetic Variability and Character Association Studies for Root Traits and Charcoal Rot Disease in Sorghum

Twenty three advanced sorghum lines along with control/standard varieties were evaluated during rabi (post-rainy) season of 2012 and 2013. Genetic variability parameters were studied for 12 characters related to root and yield traits; reaction to charcoal rot disease. Analysis of variance indicated that significant differences existed among the genotypes for all the traits studied. The estimate of genetic variability parameters indicated that a wide range of variation was evident for root length (RL), root spread, primary root, fresh and dry root weight (FRW/DRW), yield traits and disease reaction. Moderate to high heritability (ranging from 26 to 87 %) along with genetic advance as percent mean (15.98–74.73) was observed for seed yield, root volume, fresh root weight, percentage lodging (CRL), mean node crossed and mean length spread (MNC and MLS). Correlation estimates indicated significant positive correlation between root traits, such as root weight and root length (0.53**), root volume and root length (0.36**), dry root weight and root length (0.47**). While, some of the other root traits (RL, SR and FRW/DRW) were significantly negatively correlated with disease contributing traits (CRL, MNC and MLS). Seed and fodder yield were also positively correlated (0.46**), while fodder yield was negatively correlated with number of seminal roots (0.21**). Cluster analysis based on the Euclidean distances grouped all the sorghum genotypes into five clusters with SPV-86 as diverse genotype. Among the genotypes studied, GS-22 and GS-23 were found to be high yielding with reduced charcoal rot incidence.