Genetic studies of earliness in Gossypium hirsutum L.

Abstract

The present studies were designed to obtain suitable parents and crosses by estimating GCA and SCA of various traits relating to earliness, yield and fiber quality. The experiment comprised of eight genotypes including three male testers COKER310, LRA-5166 and CP-15/2 and five lines naming PB-899, FH1000, MNH-552, BH-160, CIM-496. These genotypes were crossed in a line x tester fashion and combining ability effects were computed for various traits. Both additive and non-additive genetic effects were present in controlling the plant traits. Among lines CIM-496 proved the best general combiner for almost all the traits followed by PB-899, FH-1000, BH-160 and MNH-552. Among testers best combining ability effects were shown by CP-15/2 for almost all the traits studied. The hybrids showing good specific combining effects are CIM-496 × CP-15/2 for days to squaring, days to flowering, number of bolls per plant and seed cotton yield, PB-899 × CP-15/2 for horizontal flowering interval, number of days taken to first boll opening and fiber fineness, BH-160 × LRA-5166 for boll maturation period, MNH-552 × LRA-5166 for node number for first fruiting branch, FH-1000 × COKER-310 for height of first fruiting branch, BH-160 × COKER-310 for mean maturity date and earliness index, FH-1000 × LRA-5166 for seed cotton yield and fiber length, FH-1000 × CP-15/2 for lint percentage. The results of present investigation will facilitate the selection in cotton breeding program to develop varieties possessing early maturity in early generations for the traits showing additive effects and later generation selection for the traits exhibiting non-additive genetic effects. Hybrid breeding might be fruitful in case of crosses showing vigor for yield, earliness and fiber quality.