Characterization of recombinant inbred wheat (Triticum aestivum L.) lines for heat tolerance using physiological traits and molecular markers
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Date
2017
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CCSHAU
Abstract
A mapping population of eighty lines derived from the cross between WH1021 (heat tolerant) ×
WH711 (heat susceptible) were genotyped and phenotyped under timely and late sown during 2015-16 and
2016-17 crop seasons. The present investigation was conducted to evaluate the various morpho-physiological
traits, their association with each other and to explore of the SSR markers related with heat tolerance during
terminal heat stress. Data were recorded for various morphological traits including plant height and stem
solidness at 70 and 100 days after sowing, number of days to heading, number of days to maturity, number of
tillers per plant, spike length (cm), number of spikelets per spike, grain yield per plant (g), biological yield per
plant (g), number of grains per spike, 100-grain weight (g) and physiological traits observations were recorded
at anthesis and 10 days after anthesis including canopy temperature, transpiration rate, photosynthetic rate,
stomatal conductance, intrinsic water use efficiency, chlorophyll content and NDVI. HSI for grain yield was
determined for heat stress effect assessment. Analysis of variance showed significant variation among genotypes
and reveal the genetic diversity among RILs. CTAB method was used for DNA isolation. Total ninety four
markers were used to detect polymorphism in parents out of which parental polymorphism was found 23.5%.
Genetic diversity analysis of RILs and parents was done using NT SYS-pc software based on twenty two SSRs
and Linkage map constructed using these 22 polymorphic markers consist of seven linkage groups. Composite
interval mapping (CIM) identified 14 quantitative trait loci (QTL) with significant phenotypic variation. Out of
fourteen QTLs two QTLs were detected for plant height at 70 days after sowing , two for days to heading, two
for days to maturity, two for photosynthetic rate, one for transpiration rate, four for intrinsic water use efficiency
(iWUE) and one for NDVI. Out of these QTL and photosynthetic rate were consistent and stable over the
condition and year respectively. Photosynthetic rate reported maximum phenotypic variation (78.13%) flanked
by the two markers barc24 & Xgwm102 with an interval of 27.9 cM. Two QTLs for iWUE were also consistent
and stable flanked by the markers Xgwm512 & Xgwm448 with 35.5 cM interval another Xgwm512 also flanked
the another QTL for iWUE with 5.2 cM interval. These markers can be useful for the improvement through
marker assisted selection for developing the better genotypes for heat tolerance.
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