Subhadra SinghGollen, Babita2017-06-032017-06-032013http://krishikosh.egranth.ac.in/handle/1/5810014584A total of 103 F10 RILs of bread wheat derived from HUW-510 x WH-730 were evaluated for their grain filling process under normal sown (NS) and late sown (LS) field experiments conducted in Rabi seasons of 2010-11 and 2011-12.An á-design in replicates with 15 block each was used for evaluation. The grain filling was studied by sampling the developing grains at 5 - day intervals after days to anthesis (DAA) till physiological maturity. The process of grain filling was characterized by estimating 3 parameters of grain development, namely final grain weight (W), maximum grain filling rate (R) and grain filling duration (GFD) by fitting non-linear logistic regression. Highly significant genotypic differences existed for all the three grain filling traits. However, a comparisons of : RILs with that of parents, between parents and among RILs revealed gene dispersion between parents. This inference was substantiated by the observation of transgressive segregants in both positive and negative directions for all the traits in the RIL population. Selective genotyping method of QTL detection was used and a total of 300 SSR primers were screened in a sub-population of 37 RILs and 112 primers were found to be polymorphic. Linkage map was constructed using 99 unambiguous polymorphic markers. QTL detection for W, R, GFD and also TGW and KPS was performed using single marker analysis (SMA) and composite interval mapping (CIM). A total of 61 putative QTLs using SMA and a total of 23 major QTLs were detected using CIM. Some QTLs in coupling and some in repulsion phase were observed and explained positive and negative associations respectively between traits. A number of QTLs for increasing the grain filling rate (R) and reducing the grain filling duration (GFD),were found to be useful to counteract the terminal heat stress . These QTLs may be exploited for genetic improvement of the wheat. Markers Xgwm95 and barc21 were found to be closely linked to QTLs for R and GFD and can be used for MAS after validation.enGrain, Developmental stages, Packaging, Wheats, Research methods, Genetics, Genotypes, Chromosomes, Seasons, DiseasesThesis