JAISANI, B. G.VASHI, D. R.2018-06-062018-06-061990http://krishikosh.egranth.ac.in/handle/1/5810049289Cotton occupies second position for hectarage in the country and ranks first for total production. With a view to increase productivity, a better understanding of the genetics of seed cotton yield and its attributes as tell as resistance / tolerance to spotted bollworm a major deterrent factor in increasing productivity of cotton, is essential. Hence the present study was initiated. The experimental material comprised of the diallel set (excluding reciprocals) of nine elite cotton genotypes. In all , 36 F1s and nine parental lines were sown in randomised block design, replicated twice at Anand. The spacing used was 1.2 m x 0.6 m. The observations on ten characteristics were recorded the data were analysed using Method II , Model 2 of Griffing (1956). The genetics of yield as well as resistance / tolerance to spotted bollworm was studied under natural infestation at square stage using intravarietal recombinant. The inter character association as well as cause and effect relationship (Wright, 1921) were also studied for various traits.enPLANT BREEDING AND GENETICS, AGRICULTUREA STUDYThesis