title: Physiological traits associated with heat tolerance in bread wheat (Triticum aestivum L.).
abstract: Field experiments for evaluating heat tolerance-related physiological traits were conducted for two consecutive years using a mapping population of recombinant inbred lines (RILs) from the cross RAJ4014/WH730. Chlorophyll content (Chl) and chlorophyll fluorescence (CFL) were recorded under timely sown (TS) and late sown (LS) conditions. Late sowing exposes the terminal stage of plants to high temperature stress. Pooled analysis showed that CFL and Chl differed significantly under TS and LS conditions. The mean value of CFL (Fv/Fm) and Chl under both timely and late sown conditions were used as physiological traits for association with markers. Regression analysis revealed significant association of microsatellite markers viz., Xpsp3094 and Xgwm131 with coefficients of determination (R (2)) values for CFL (Fv/Fm) and Chl as 12 and 8 %, respectively. The correlation between thousand grain weight (TGW) with Chl and CFL were 14 and 7 % and correlation between grain wt./spike with Chl and CFL were 15 and 8 %, respectively. The genotypes showing tolerance to terminal heat stress as manifested by low heat susceptibility index (HSI = 0.43) for thousand grain weight, were also found having very low Chl, HSI (-0.52). These results suggest that these physiological traits may be used as a secondary character for screening heat-tolerant genotypes.
authors: Directorate of Wheat Research, Karnal, 132001 Haryana India.
authors: Girish Chandra
authors: GC
authors: Pandey
authors: Directorate of Wheat Research, Karnal, 132001 Haryana India.
authors: H M
authors: HM
authors: Mamrutha
authors: Directorate of Wheat Research, Karnal, 132001 Haryana India.
authors: Ratan
authors: R
authors: Tiwari
authors: Directorate of Wheat Research, Karnal, 132001 Haryana India.
authors: Sindhu
authors: S
authors: Sareen
authors: Department of BT and BI, Jaypee University of Information Technology, Solan, 173234 Himachal Pradesh India.
authors: Shrutkirti
authors: S
authors: Bhatia
authors: Chaudhary Devi Lal University, Sirsa, 125055 Haryana India.
authors: Priyanka
authors: P
authors: Siwach
authors: Directorate of Wheat Research, Karnal, 132001 Haryana India.
authors: Vinod
authors: V
authors: Tiwari
authors: Directorate of Wheat Research, Karnal, 132001 Haryana India.
authors: Indu
authors: I
authors: Sharma
keywords: Chlorophyll content; Chlorophyll fluorescence; Heat stress; Microsatellite markers; Wheat
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