Effect of Heat Stress on Growth, Physiology and Productivity in Different Wheat Species
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Date
2012
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UAS, Dharwad
Abstract
A field experiment was conducted during rabi season of 2011-12 at Main
Agricultural Research Station, University of Agricultural Sciences, Dharwad to
evaluate the effect of heat stress on growth, physiology and productivity in different
wheat species under normal irrigated conditions. The experiment consisted of 12
genotypes (UAS-320, NIAW-1415, NIAW-34, HI-1571, DWR-1006, UAS-415,
UAS-428, UAS-439, DDK-1025, DDK-1029, MACS-2971 and HW-1098) belonging
to cultivated species viz., Triticum aestivum, Triticum durum and Triticum dicoccum
and were laid out in a factorial randomized block design (FRBD) with three
replications. The different temperature regimes were maintained by manipulating the
date of sowing.
Significant differences were observed in morphological, growth,
physiological, biochemical, yield and yield parameters with different temperature
regimes. Among the treatments, low temperature regime exhibited superiority over
high temperature regime, while giving a better response to most of the yield
contributing characters such as more number of branches, more number of nodes,
more leaf area, more TDM, higher percentage of dry matter partitioning into
economically useful parts, higher AGR, CGR, SLW, LAI, LAD, BMD, higher
photosynthetic rate, higher chlorophyll content, higher chlorophyll stability index,
maximum membrane thermostability, higher canopy temperature, higher heat stress
index, higher protein content and higher b-carotene content ultimately resulting into
more number of spikes, more spike length and weight and 1000- grain weight, thus
resulting in higher grain yield.
The grain yield was found positively and significantly correlated with
chlorophyll stability index, canopy temperature, membrane thermo stability index,
wax deposition, relative water content, and 1000- grain weight. The genotypes UAS-
439, UAS-415 and UAS-428 performed better both in low and high temperature
regimes, thus indicating their use in breeding the wheat genotypes for tolerance to
heat stress.