ABSTRACT

A study to investigate the extent of heterosis in crosses, combining ability among six selected lines and five testers in upland cotton (Gossypium hirsutum L.) was conducted at Botany Garden College of Agriculture Dharwad during kharif 2023-24. A total of thirty hybrids were derived from Line × Tester (L × T) mating design and analysed for yield, yield attributes along with fiber quality traits. Among the thirty hybrids evaluated, RAH-1083 × Sunantha, SCS-793 × RAH-19-2 and SCS-793 × Suraksha were the most potential hybrids in terms of yield and yield attributes. These crosses exhibited more number of bolls per plant, higher seed index, higher ginning outturn with moderate boll weight and number of sympodia per plant which are ideal traits for high seed cotton yield. Crosses, RAH-1075 × Subiksha and RAH-1081 × Suraksha recorded desirable fibre quality parameters.
The combining ability analysis indicated the presence of non-additive gene action for all the characters investigated except for plant height and micronaire value. Among lines, SCS-793 and BGDS-1063 among testers, Sunanth, Suraksha and RAH-19-2 were rated as high general combiners based on their overall gca effects. The potential crosses involved either both parents with high gca effects or one of the parents with high gca effects. A set of eleven parents were subjected to molecular diversity analysis using SRAP markers and two clusters were formed indicating considerable diversity among the parents for the selected traits. The top performing lines with significant positive gca effect and the crosses with significant positive sca effect can be further utilised in the future cotton improvement programs.