Development of superior hybrids for fibre quality based on heterosis and combining ability in upland cotton (Gossypium hirsutum L.)

The cultivated Gossypium spp. represents the most important, natural fibre crop in the world. Breeding for high cotton yield is still the primary goal of cotton breeding programs, but improving fibre quality has become increasingly important. The enhancement of fibre quality traits like fibre length, strength, and fibre fineness is an essential requirement for the modern textile industry. The objective of this study was to facilitate the selection in cotton breeding program and estimate the general combining ability (GCA) of the parents and specific combining ability (SCA) of hybrids considered for the development of high yielding and better fiber quality in early generations. The study was carried out at cotton research area, CCS Haryana Agricultural University, Hisar (India) during 2014 and 2015 kharif season. Fifteen cotton lines (which have maximum diversity) and four testers (which are known as well adapted and high yielding) were crossed in a line x tester mating design in 2014. Nineteen genotypes and 60 F1 hybrids were planted in the randomized complete block design with three replications at the same experimental area in 2015. The ratio of δ2 GCA /δ2 SCA was less than unity for all the nine characters indicating preponderance of non-additive gene action (dominance and epistasis), which is an important in exploitation of heterosis through hybrid breeding. The best general combining ability was detected from the parent H1470 for seed cotton yield, H1464 and H1098-i for fiber quality traits. SCA was significant for AC726 x H1236, ISR12 x H1226, HR1 x H1117 hybrid combinations for yield and fiber quality. The crosses H1470 x H1236 and H1470 x H1098-i were reported good heterosis for seed cotton yield as well as for fibre quality, selected the best hybrids were H1464 x H1098-i and H1463 x H1226. These cross combinations involved at least one parent with high or average GCA effect for a particular trait. The cross combination involving H1470, H1098-i and H1464 parents’ recorded significant positive heterosis with acceptable SCA effect for both yield and fibre quality parameters. This investigation concluded that the parents H1470, H1098-i and H1464 can be used in hybrid development programme with better fibre quality.