Physiological Basis of Temperature Tolerance in Wheat (Triticum sp.) Genotypes
Loading...
Date
2016-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
University of Agricultural Sciences, Dharwad
Abstract
ABSTRACT
A field experiment was conducted during rabi, 2015-16. Different temperature regimes were maintained by manipulating the date of sowing. The experiment consisted of two dates of sowing viz., 211.2015, 15.12.2015 (D1, D2 temperature regimes respectively) and nine wheat genotypes. Most of morpho-phenological, physiological, biochemical and quality parameters indicated better performance under D1 temperature regime.
Various morpho-phenological parameters studied indicated that the genotypes HW-1098, UAS-459, UAS-415 and UAS-304 performed better under both D1 and D2 temperature regime over other genotypes. Under D2 temperature regime, maximum leaf area was recorded by DDK-1045 (36.86 dm2 hill-1). Similarly maximum total dry matter (16.41 g hill-1 at harvest), relative water content (64.28 % at 30 DAA), canopy temperature depression and growing degree days for physiological maturity (1608.98) were observed in HW-1098 under D2 temperature regime. Maximum cell membrane thermo stability (55.52 %) was observed in UAS-415 at 30 DAA under D2 temperature regime. The genotypes HW-1098, UAS-415 and UAS-459 recorded maximum osmolyte concentration. HW-1098 maintained highest photosynthetic rate under D2 temperature regimes which may be due to highest stomatal conductance and transpiration rate.
The genotypes DDK-1045, DDK-1046, NIAW-34 and HD-3090 had the maximum per cent reduction of chlorophyll a, indicating the sensitive nature of these genotypes to increase in the growth temperatures. The minimum reduction in chlorophyll stability index was observed in HW-1098 (3.22%). Reduction in yield due to high temperature was mainly attributed to the significant reduction in the number of tillers, 1000-grain weight, number of spikes and number of spikelet. HW-1098 maintained highest yield in both the temperature regimes with minimum per cent yield reduction (24.79) as compared to all other genotypes, substantiating that the genotype HW-1098 is relatively heat tolerant.