Patil, Rajesh S.Sankeshwar, Mahantesh2021-10-042021-10-042016-08https://krishikosh.egranth.ac.in/handle/1/5810176623An investigation was carried out to identify QTLs for trichome traits implicated in jassid resistance of cotton. A set of 200 recombinant inbred lines derived from the cross Gossypium hirsutum var. DS-28 and Gossypium barbadense var. SBYF-425 was evaluated separately under both protected and unprotected conditions for trichome traits study and jassid incidence respectively, during kharif 2015-16 at the Agricultural Research Station, Dharwad Farm, Dharwad. The mean data of leaf pubescence and yield traits were subjected to analysis of variance and QTL mapping. Analysis of variance revealed significant differences among the RILs for leaf pubescence and productivity traits indicating the presence of substantial variation among the recombinant inbred lines. The jassid population and injury grade were significantly and negatively correlated with leaf pubescence traits viz., abaxial leaf pubescence count, leaf mid-rib pubescence count and leaf vein pubescence count. Notably, the trichome length did not show any relation with either trichome density or jassid numbers on the leaf. Seed cotton yield recorded positive phenotypic correlation with number of bolls per plant and boll weight. The genetic linkage map using 178 recombinant inbred lines constructed earlier was used to analyze and map the QTLs for leaf pubescence, jassid injury resistance and yield traits. QTL mapping software QciMapping was used to analyze the data by single marker analysis, simple interval mapping and composite interval mapping. A total of forty two QTLs were detected on eleven chromosomes, each explaining 7.61 to 18.88 per cent phenotypic variation with peak LOD score of 3.04 to 5.79. Out of forty two QTLs, fifteen affected the leaf pubescence traits, three affected jassid injury resistance and twenty four affected the yield and yield contributing traits. These identified markers associated with leaf pubescence and yield traits can be effectively utilized for maker assisted selection after validation.EnglishThesis