*Corresponding author:A Nishant Bhanu, Department of Genetics and Plant Breeding, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India; Email: firstname.lastname@example.org
Received: December 12, 2017; Published: January 08, 2018
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Twenty genotypes of wheat were undertaken for assessment of direct selection parameters (variability, heritability, and genetic advance), indirect selection parameter (correlation) and their relation with heat tolerance. This investigation was carried out at the Agriculture Research Farm of Institute of Agriculture Sciences, Banaras Hindu University, Varanasi during the Rabi season of 2011-12 and 2012-13 in randomized block design with 3 replications. Observations were recorded on grain yield and its related traits, viz., days to heading, days to anthesis, days to maturity, grains per spike, 1000 grain weight. Besides these, chlorophyll content at heading and at anthesis stages as well as canopy temperature depression (CTD) from vegetative stage to dough stages were studied. All the traits like days to heading, days to anthesis, days to maturity and 1000 grain weight exhibited high heritability, which was coupled with high genetic advance as per cent of mean was recorded for 1000 grain weight and yield per plot. That indicated effectiveness of selection for the improvement of these traits.
The 1000 grain weight, i.e., test weight, as the most important yield attribute was found positively and significantly associated with CTD at early and late milking stages suggesting that higher seed weight is possible in varieties which show high CTD, i.e., low canopy temperature in heat stress conditions. Among the component traits, days to heading had positive and significant correlation with days to anthesis, and days to maturity. Interestingly, this result suggests that for the selection of early heading genotypes, days to anthesis and days to maturity should be invariably considered for wheat improvement. Further, plot yield had non-significantly negative association with days to maturity indicating that the early genotypes in semi-arid condition are capable of escaping the terminal heat stress, which is the major yield reducing factor. The twenty genotypes studied, represented considerable and diverse variability for different traits evaluated and significant associations on yield which could be utilized in breeding programme for varietal improvement in wheat.
Keywords: Wheat; Canopy Temperature Deficit; 1000 Grain Weight; Days to Heading; Days to Anthesis
Abbreviations: CTD: Canopy Temperature Depression; PCV: Phenotypic Coefficient of Variation; GCV: Genotypic Coefficient of Variation