Heat stress is a major yield limiting factor of wheat productivity in India. Therefore, development of high temperature tolerant wheat
genotype is an important objective of wheat breeding. Significant differences for the years, genotypes and their interactions indicated
that the responses of genotypes under heat stress varied not only among themselves, but also over the years. This suggested the need
for evaluation of wheat genotypes over a wide range of environments/years for obtaining consistent expression for heat tolerance.
There was considerable influence of high temperature stress in both years as grain yield was reduced nearly about 50% under late
sown experiment as compared to that of timely sown conditions. Only one genotype, i.e., Raj 3765 have shown significantly high
yield under both conditions indicating a complementation of high yield and heat resistance genes. The genotypes DBW 88, HD
2967, HI 1563, HI 1571, NIAW 1951, Raj 4083 and UP 2425 were with significantly high yield under timely sown, while HD 2932,
PBW1 75, PBW 373, Raj 3765, UAS 320, WH1124, WH 1142 and WH1164 were promising for grain yield under heat stress and
for physiological parameters undertaken. Indices of heat tolerance, i.e., heat response index (HRI) and heat susceptibility index
(HSI) were the most promising traits because of their strong associations with heat tolerance parameters, namely, tetrazolium
triphenyle chloride test (TTC) and cell membrane stability (CMS), and due to their significance for their mean values for majority
of the genotypes under heat stress conditions. In addition, the above traits had a contribution of about 70% of the total variation for
heat tolerance as revealed by principal component analysis in the material under study. The diversity and spatial analysis revealed
that the contrasting genotypes in terms of heat tolerance and spatial distribution may generate the desirable segregating material for
improvement of heat tolerance in bread wheat.
Journal Section | Articles |
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Authors | |
Publication Date | January 31, 2017 |
Published in Issue | Year 2017 Volume: 3 Issue: 2 |