Genetic analysis of yield and heat stress related traits in wheat (Triticum aestivum L. em. Thell) using microsatellite markers
Microsatellite markers were used for genetic analysis of terminal heat tolerance in F2 (PBW373 × WH1081) population of wheat (Triticum aestivum L. em. Thell). Two parents were evaluated in field under normal sown and late sown conditions. For genotyping DNA from both parents PBW373 and WH1081 was amplified using 200 SSRs. Only 22 SSRs produced polymorphic bands, of size between 100 to 300 bp and an average of 1.45 alleles. The single marker analysis identified 19 markers indicating the putative QTLs for yield, its components and heat stress related physiological traits. The number of markers on these 16 linkage groups varied from one to four. On A genome 13 QTLs on B genome 5 QTLs and on D genome 9 QTLs were identified, respectively. The A, B and 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 on definitive location on chromosome 3A (QDh.CCSHAU-3A, QDa.CCSHAU-3A and QPm.CCSHAU-3A), chromosome (QBm.CCSHAU-5A, QCtd.CCSHAU-5A and QCl.fl.CCSHAU-5A), chromosome6A (QPh.CCSHAU-6A) and chromosome3B (QTgw.CCSHAU and QMts.CCSHAU-3B). Use of these markers save times, resources and energy that are needed not only for raising large segregating populations for sveral generations, but also for estimating the parameters used for selection.