B. M. KhadiPatil Malagouda2016-07-262016-07-262013http://krishikosh.egranth.ac.in/handle/1/69873Cotton is one of the most important commercial crops grown in India. It is the world’s leading natural fibre crop and is the cornerstone of textile industries worldwide. Inspite of several competitions from synthetic fibres, cotton continues to enjoy a place of prime importance in textile industry. As diploid cottons are well suited to rainfed ecosystem and can fulfil the increasing demand for medium staple nature of fibres, it still necessitates having diploid cottons with improved fibre quality. The present investigation was undertaken to construct the genetic map and to identify QTLs for important yield contributing and fibre quality traits using 50 polymorphic SSR markers in 154 recombinant inbred lines (RILs) derived from the cross between G. herbaceum variety Jayadhar and G. arboreum variety DLSa17. Genetic variability components revealed higher magnitude of variation for most of the traits. This was evidenced by high range and mean performance for different traits in RILs. Per se performance of RILs indicated the improvement over parents for various productivity and fibre quality traits. Association among different traits under study revealed, significant association of seed cotton yield with ginning out turn and lint yield. Fibre length exhibited highly significant positive correlation with fibre strength (0.41) and fibre elongation (0.48). Genetic linkage map was constructed with 50 polymorphic markers. The total map length was 4033.95cM with average distance of 80.68cM between the markers. Out of 15 QTLs detected, seven QTLs were for seed cotton yield. The chromosome 6 harboured QTLs for more than one trait viz., ginning out turn, seed cotton yield, lint yield and uniformity ratio. Three QTLs each corresponding to seed cotton yield, lint yield and uniformity ratio were present between NAU2964 and MUSB1248. The construction of ‘A’ genome diploid map with SSR markers, can serve as a model for the advancement of cotton genetics and genomics. Adding additional markers to the existing map to saturate the map will assist in future map based cloning efforts and fine mapping studies.Thesis