SomveerVekariya, Rajesh Dhanji2016-10-242016-10-242016http://krishikosh.egranth.ac.in/handle/1/81568The present study comprised eighty Gossypium arboreum L. genotypes viz., sixty hybrids, their parents (i.e. four females and fifteen males) and one check hybrid AAH 1. The crosses were attempted in Line x Testers mating design. All the hybrids along with parents and check were grown at research area of Cotton section, Deptt. of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar, in a randomized block design with three replications during kharif 2015. Observations were recorded for thirteen characters namely, days to first flower, number of monopods, number of bolls per plant, plant height, boll weight, seed cotton yield per plant, number of seeds per boll, ginning out turn, seed index and lint index and biochemical parameters like oil content, protein content and gossypol content. Out of sixty hybrids studied, a total thirty three hybrids showed positive heterobeltiosis and seventeen hybrids showed positive economic heterosis over standard check, AAH 1 and thirty nine crosses showed positive average heterosis for seed cotton yield. In order of merit of F1 hybrids DGMS 34 x HD 517 (53.19%), DGMS 34 x HD 523 (40.00%), DGMS 2 x HD 528 (39.96%) and DGMS 1 x HD 432 (39.97%) recorded highest positive standard heterosis for number of bolls, seed cotton yield and lowest gossypol content, while the maximum heterobeltiosis for seed cotton yield per plant was exhibited by the hybrids DGMS 2 x HD 528 (121.82%) followed by DGMS 1 x HD 432 (114.48%) and DGMS 1 x CNA 398 (84.62%). Hybrids DGMS 1 x HD 432 and DGMS 2 x HD 528 showed good heterotic performance over mid parent, better parent and standard check (AAH 1) for number of bolls and seed cotton yield. DGMS 34 x HD 517 for reducing level of gossypol and DGMS 1 x LD 1026 for high level of protein while DGMS 9 x CNA 398 for high level of oil content over standard check AAH 1. The combining ability study revealed that male parent HD 517 was best general combiner for seed cotton yield, number of bolls, boll weight, number of monopods, days to first flower and gossypol content. The second best combiner for seed cotton yield was CNA 398, which was also found to be best combiner for number of bolls, boll weight, number of monopods and ginning out turn. Among male parents HD 534 was found best combiner for ginning out turn, boll weight, number of seeds per boll and days to first flower for earliness, HD 528 for protein content, CNA 398 and HD 532 for oil content and HD 523 and HD 432 and among female parents, DGMS 34 was found highest GCA effects for reducing level of gossypol content. For seed cotton yield and yield related traits the good SCA effects were observed in the cross DGMS 2 x HD 528, DGMS 1 x HD 432, DGMS 34 x HD 517 and DGMS 34 x HD 523 along with good per se. DGMS 1 x LD 1026 for oil content, DGMS 1 x HD 503 for protein content and DGMS 34 x HD 534 for reducing gossypol content exhibited significant SCA effect.enHeterosis, Combining ability, Gossypium arboreum L. Cotton.Thesis