Genetic diversity for yield and morpho-physiological traits in foxtail millet (Setaria italica (L.) P. Beauv.)

Genetic diversity is a cornerstone of successful plant breeding programs, particularly for enhancing yield and stress tolerance in crops like foxtail millet. This study evaluated the genetic divergence among 40 foxtail millet genotypes based on 18 yield and morpho-physiological traits using Mahalanobis D² statistics. The analysis revealed significant genetic variability, with genotypes grouped into six distinct non-overlapping clusters using Tocher’s method. Cluster I was the largest (14 genotypes), while Cluster II was monogenotypic, indicating high heterogeneity. Inter-cluster distances (506.52–3158.48) consistently exceeded intra-cluster distances (0–353.56), highlighting greater diversity between clusters. Cluster means varied significantly for traits such as days to 50% flowering (32.50–58.75 days), plant height (38.67–108.89 cm), and grain yield per plant (2.68–7.82 g). Cluster VI exhibited superior means for traits like days to maturity and panicle length, while Cluster IV excelled in grain yield and harvest index. Protein content (29.49%), transpiration rate (24.36%), and grain yield per plant (11.54%) were the primary contributors to genetic divergence. The results suggest that strategic hybridization between accessions from divergent clusters, particularly Clusters II and V, could generate superior recombinants with enhanced genetic potential for yield and stress tolerance in foxtail millet breeding programmes.