Molecular characterization of wheat (Triticum asetivum L.em.Thell) under terminal heat stress
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Date
2012
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CCSHAU
Abstract
The objectives of present investigation were to determine the genotypic variation for grain yield, its components and morpho-physiological traits to study the DNA polymorphism in recombinant inbred lines (RILs) grown under terminal heat stress conditions. The characters observed were grain yield per plant, number tillers, 100-grain weight, grain weight per spike, number of grains per spike, spike length, number of spikelets per spike, days to heading, days to physiological maturity, plant height, harvest index, biomass per plant, canopy temperature depression, membrane thermostability, chlorophyll fluorescence and stomatal conductance. Results revealed that the mean sum of squares due to genotypes were significant for all the characters indicating sufficient magnitude of variations. Correlation coefficients showed that genotypes having high grain yield were also better in number of tillers per plant, number of grains per plant, grain weight per spike, number of grains per spike, biomass per plant, plant height, harvest index and have high canopy temperature depression and membrane thermostability indicating the importance of these characters for high grain yield under heat stress conditions. The magnitude of direct effects showed that biomass, harvest index, numbers of grains per plant and 100-grain weight were important for improvement of grain yield under heat stress conditions. Based D2 values, eleven clusters were formed by grouping all the 125 RILs and their parents. Molecular characterization of RILs revealed that grouping of RILs was not similar to that of morpho-physiological traits. This may be due to the fact that the markers of molecular characterization may not be sufficient to explain the total variation on the basis of morpho-physiological characters. Major group I consisted of WH 147 and 21 RILs, while the major group II had WH 730 and 104 RILs. Cluster as well as PCA analysis clearly indicated that the RILs were scattered between both parents. Genotypes, WH147 and WH 730 indicated a wide special distance.
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Keywords
Grain, Wheats, Planting, Yields, Genotypes, Genetics, Developmental stages, Biological phenomena, Tolerance, Bakery products