Combining ability and heterosis for yield contributing traits in upland cotton (Gossypium hirsutum L.).

A 4x4 complete diallel crosses between Sadori, CRIS-134, Sohni and CIM-448 was designed in F1 generation to estimate the general and specific combining abilities of genotypes and to determine the degree and direction of heterosis and selection of promising recombinants for future breeding programme. The experiment was conducted in RCBD in three replication at experimental farm of Nuclear Institute of Agriculture, Tando Jam during 2005-06 for the traits plant height, sympodia/plant, bolls/plant and seed cotton yield/plant. The results of GCA showed that the variety Sadori proved to be best general combiner for plant height, number of bolls/ plant and seed cotton yield while the crosses Sadori x CIM-448 and Sadori x CRIS-134 exhibited higher SCA effects for boll number/plant. All the crosses showed positive magnitude of heterosis over mid and better parental means for plant height. The crosses Sadori x CIM-448 followed by CIM-448 x Sohni exhibited positively higher heterosis and heterobeltiosis for number of bolls /plant and seed cotton yield/plant.