Abstract

                                The seeds of Gossypium are usually fuzzy of different grades. The combining ability on oil content in relation to fuzz grades is reported in this paper. Seven cotton lines differing in fuzz grade from fully fuzz to naked seeds were crossed with the fuzzy varieties: MCU.5, MUC.7, MCU.9 and LRA. 5166 in a 'line x tester' fashion. Seed oil percentage exhibited greater range of variation among hybrids (16.55 to 23.58). The naked seed parent, TCH.89/7 recorded the highest significant oil percentage (23.66) and hybrids involving naked seed parent also recorded significantly higher oil percentage. Heritability (broad sense) was as high as 94.6 per cent though, the genetic advance as percentage of mean was low (8.49%). The GCASCA ratio was also less than unity indicating the preponderance of non-additive gene action for oil content. Significant relationship between the per se performance and gea effects of the parents for oil content was noticed with sparsely fuzzed line TCH.65/8 and naked seed line TCH.89/7. Bot the cross combinations with high sea effects with respect to oil content involved poor conbiners. Correlation studies revealed that seed oil content had a significant and negative correlation co-efficient (-0.34) with fuzz grade and had significant and positive correlation co-efficient (0.34) with single seed kernel weight.

Key words : Cotton, Gossypium hirsutum, seed, oil content combining ability