Combining ability for maturity traits was studied in pearl millet. Ten parents selected through a field screening technique for their different response to supra-optimal temperature tolerance were crossed in a diallel manner. Forty-five F1 hybrids along with their 10 parents were tested for their performance under supra-optimal temperature exposure at seedling stage with an objective to understand the nature of gene action and to identify parents for breeding programme. The experiment was conducted in three different environments created through different dates of sowing from May to July. The Griffings method of diallel analysis was used to obtain the genetic estimates. Variances due to general combining ability and specific combining ability for all the characters studied, viz., Seedling Thermo-tolerance Index (STI), Seed to Seedling Thermo-tolerance Index (SSTI), panicle emergence, effective tillers, plant height, ear length, ear weight, dry fodder yield, grain yield/plant and total biological yield/plant were highly significant in all the three environments (two stress and one normal) and on pooled basis indicating the importance of both additive and non-additive gene actions. The genotype CVJ-2-5-3-1-3 was identified as the best general combiner for STI as well as maturity traits, while, the genotype (77/371xBSECT CP-1) exhibited highest GCA effects for SSTI in both the stress environments. The genotype (77/371xBSECT CP-1) had high GCA effects for STI and SSTI as well as panicle emergence for earliness. Broad sense heritability (h2bs) was quite high for all the characters studied. However, the estimates of additive genetic variance and narrow sense heritability for STI and SSTI also indicated good chances of effective selection. Preponderance of non-additive (dominance component) was recorded for all the characters suggested the success of hybrid breeding by making use of the expected heterosis. Heat tolerance indices STI and SSTI were not showing any perceptible correlation with either of the maturity traits suggested that pearl millet has great resilience and recovery after stress period during seedling stage.
Ashok Kumar Yadav, M.S. Narwal and Rajesh Kumar Arya, 2012. Study of Genetic Architecture for Maturity Traits in Relation to Supra-optimal Temperature Tolerance in Pearl Millet (Pennisetum glaucum (L.) R.Br.). International Journal of Plant Breeding and Genetics, 6: 115-128.