Genetic Diversity Studies in Coloured Pericarp Sorghum Genotypes (Sorghum bicolor L. Moench)

Abstract

A total of 81 genotypes were evaluated to estimate genetic diversity using Mahalanobis D² statistics and Tocher’s clustering method for morphological and shoot fly tolerance traits. Based on the D² analysis, the genotypes were grouped into eight clusters for morphological traits and six clusters for shoot fly-related traits, indicating substantial genetic divergence among the material studied. Among the 13 morphological characters, the highest contribution to total genetic diversity was recorded for glume colour (39.10%), grain color (32.75%), plant height (11.33%), and number of primaries per panicle (10.96%). For the six shoot fly tolerance traits, adaxial (69.23%) and abaxial (24.69%) trichome density, followed by shoot fly dead hearts (4.72%) and seedling glossiness (0.51%), contributed most to the observed variability. The maximum inter-cluster distance was recorded between clusters V and VII (D=57.91) for morphological traits and between clusters V and II (D=80.81) for shoot fly traits, suggesting that genotypes in these clusters are genetically most distant and offer high potential for hybridization to obtain desirable recombinants. Cluster mean analysis revealed considerable variation particularly for plant height, days to 50% flowering, trichome density, and dead heart percentage at 28 DAS. These traits may serve as effective selection criteria for further breeding and for developing transgressive segregants with enhanced shoot fly tolerance and improved agronomic performance.

KEYWORDS

D² statistics, trichome, clusters, Genetic diversity.