Genetic diversity analysis for high temperature stress tolerance in pearl millet [Pennisetum glaucum (L.) R. Br]

The present study was conducted to evaluate the genetic divergence among thirty-eight elite pearl millet genotypes using Mahalanobis D2 statistics for thirteen different agronomic, morphological and thermotolerance traits, under rain-fed condition. Analysis of variance indicated considerable diversity among genotypes showing significant variability for all the characters including thermo-tolerance. D2-clustering grouped the genotypes into 3 clusters, in which leaf sheath length (11.95 %), leaf blade length (11.61 %), leaf blade width (9.48 %) and MSI (9.33 %) contributed significantly for the genetic divergence observed among genotypes. Cluster II was characterised with genotypes having higher values of MSI and other leaf characters which got associated with higher yield and yield contributing characters. Screening genotype for seedling thermo-tolerance suggested, 841B as most tolerant (MSI = 71.2 %) and PPMI 69 as most susceptible genotype (MSI = 52.5 %). Maximum inter cluster distance was observed between clusters II and III (4.132), while maximum intra cluster distance was observed in group III (3.079). The pattern of distribution of genotypes belonging to same eco-geographical areas was random, which indicated that there was no association between genetic diversity and eco-geographical distribution of genotypes. The clustering of genotypes will help to identify divergent genetic material for obtaining highly heterotic pearl millet hybrid with thermo tolerance through hybridisation.