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Genetic analysis of terminal heat tolerance in wheat using molecular markers

KrishiKosh

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Title Genetic analysis of terminal heat tolerance in wheat using molecular markers
 
Creator Gupta, Mamta
 
Contributor Chawla, Veena
 
Subject grain, developmental stages, yields, wheats, planting, tolerance, biomass, genotypes, biological phenomena, genetics
 
Description The present investigation was carried out for genotyping and phenotyping of F2 population for heat tolerance in wheat and identification of putative QTLs using F2 population of cross PBW373 x WH1081 and PBW373 x PBW343. Three parents and four check varieties (Raj3765, WH730, DBW17 and WH711) were evaluated in field under normal sown (29.Nov.2011)and late sown (3.Jan.2012) conditions. Two factor ANOVA exhibited highly significant differences for genotypes, environments, as well as for genotype x environment interactions for days to heading, days to anthesis, days to physiological maturity, grain filling duration, plant height, number of productive tillers/plant, number of grains/spike, 1000 grain weight, grain yield/plant, biomass/plant, harvest index and membrane thermostability. HSI (Heat susceptibility index) for 1000 grain weight and grain yield/plant was observed to be significantly low in all tolerant genotypes (PBW373, Raj3765 and WH730). The performance of sensitive parents was affected to more extent in late sown conditions as compared to that in tolerant parents. Grain yield/plant showed a positive correlation with plant height (0.69**, 0.28**), biomass/plant (0.98**, 0.94**) and number of productive tillers/plant (0.89**, 0.85**) in both the crosses. For genotyping DNA from three parents PBW373, WH1081 and PBW343 was amplified using 200 SSRs. 158 SSRs showed amplification in parents. Only 22 SSRs produced polymorphic bands, of size between 100 to 300 bp and an average of 1.45 alleles. No polymorphism was observed in parents of other population. SSR amplification profile of 152 F2plants was used for identification of QTLs using QTL Cartographer version- 2.5. The single marker analysis identified 19 markers indicating the putative QTLs for yield, its components and heat stress related physiological traits. A total 22 SSRs were used to construct the map and these were found to be mapped on 16 linkage group. The number of markers on these 16 linkage groups varied from one to four. On A genome 13 QTLs were identified, on B genome 5 QTLs and on D genome 9 QTLs recepectively. The A-, Band D- genomes had 1360.3 cM, 272.4 cM and 919.5 cM of linkage coverage with average interval distances of 104.63 cM, 54.48 cM and 102.16 cM/Marker. A total of nine QTLs were resolved following composite interval mapping,one QTL was detected at a LOD score equal to threshold value of 2.5 while eight at LOD scores above the threshold value. All the nine QTLs were shown to be definitive located on chromosome 3A (QDh.CCSHAU-3A, QDa.CCSHAU-3A and QPm.CCSHAU-3A), cromosome 5A (QBm.CCSHAU-5A, QCtd.CCSHAU-5A and QCl.fl.CCSHAU-5A), chromosome 6A (QPh.CCSHAU-6A) and chromosome 3B (QTgw.CCSHAU and QMts.CCSHAU-3B). Positive QTL effect suggested that an allele of the above QTL for heat stress tolerance is available in the tolerant parental genotype PBW373. These putative QTLs indicated by the SSRs may be used in MAS after further validation using another mapping population.
 
Date 2016-02-09T11:52:17Z
2016-02-09T11:52:17Z
2014
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/64233
 
Language en
 
Format application/pdf
 
Publisher CCSHAU