The present study was undertaken to determine effectiveness of selection for genotypes tolerant to heat stress using differences in tiller per plant (dTPP), grain weight per plant (dGWPP), grain number per plant (dGNPP), biomass per plant (dBMPP) and spike length (dSL) under the optimum and late sown field condition. A Recombinant Inbred Line (RIL) mapping population derived from theheat sensitive genotype Raj 4014 and heat tolerant genotype WH730 was evaluated for the heat stress over 2 years in a replicated trial under optimum or timely (TS) and late sown (LS) field conditions. Parents and their RILs clearly showing variation with respect to the dTPP, dGWPP, dGNPP, dBMPP and dSL. There was differential response of genotypes under LS as compared to the TS. The field data recorded under precision planting using the dibbling method was very effective in capturing the data under both conditions. Considering the two sowing condition viz., LS and TS, mean of difference in tiller per plant (dTPP) was 1.64. While for grain no. per plant (dGNPP) and grain weight per plant (dGWPP), the mean differences observed between TS and LSwere 76.55 and 3.02 g respectively. Difference in spike length (dSL) was 1.09 cm and biomass per plant (dBMPP) showed difference of 8.41 g.
The authors acknowledge the ICAR for financial support for carrying out the work under NPTC project: Functional Genomics in wheat. Authors also thankful to Prof. Aditya Shastri, Vice-Chancellor, Banasthali Vidyapith for providing opportunity to complete my manuscript writing.