Inheritance studies for earliness, yield and fibre traits using simplified triple test cross in G. hirsutum

The simplified triple test cross analysis provides a precise test for epistasis along with unambiguous estimates of additive and dominance genetic variance. Different generations of simplified triple test cross analysis grown in a randomized complete block design with three replications were evaluated for major quantitative characters of earliness, yield and fibre quality. The analysis of variance for epistasis revealed the presence of epistasis for most of the characters studied. The analysis of variance for sums indicated the presence of additive genetic component in the inheritance of most of the characters except for number of monopods and sympods per plant, plant height, bolls at first sympod, bolls at sympod at 50 per cent plant height, boll weight, fibre strength and fibre quality index. Whereas the analysis of variance for differences indicated the involvement of dominance component in the inheritance of length of first sympod, days to maturity, seed cotton yield, number of bolls per plant, lint yield, ginning outturn, 2.5% span length, fibre fineness and fibre maturity. Both additive and dominance components of genetic variation were observed to be involved in the inheritance of length of first sympod, days to maturity, seed cotton yield, number of bolls per plant, lint yield, ginning outturn and 2.5% span length. Out of these, length of first sympod, days to maturity, number of bolls per plant, ginning outturn and 2.5% span length showed higher magnitude of dominance genetic component indicating degree of dominance to be in the range of over dominance. The appropriate breeding methods for the improvement of different characters have been discussed.