Inheritance, heterosis and combining ability analysis in line × tester crosses of cotton

Abstract. The aim of this research was to study heterosis, combining ability and genetic control of most important traits in line × tester crosses. It was found that the non-additive variance (σ2D) was larger than the additive variance (σ2A) for productivity per plant and fiber length revealing the greater importance of non-additive gene action in the inheritance of both traits and the selection of desirable forms should be conducted in the later hybrid generations. Non-additive genetic variance was also more important for boll weight, whereas additive gene action was of greater importance for lint percentage and the selection for this trait can be effective in early segregated generations. Line 266 was identified as a good general combiner for productivity per plant and fiber length, line 346 for lint percentage and fiber length. The Turkish cultivar Nazili 954 can be used in crosses to improve productivity, while the Spanish cultivar FR-H-1001 can be used to increase lint percentage and fiber length. The hybrids 191 × Nazili 954 and 266 × FR-H-1001 exhibited the highest productivity per plant with high SCA effects and the highest heterosis of 30.7-31.7%. The highest lint percentage of 42.1-42.3% was achieved in hybrids from the crosses Nazili 954 × 266 and 346 × FR-H-1001 showing significant positive heterosis of 2.4 - 9.0%. Hybrids from the crosses FR-H-1001 × 266 and 346 × FR-H-1001 had the longest fiber and exhibited heterosis of 8.4% and 5.7%, respectively. The cross combination 346 × FR-H-1001 was very promising for lint percentage and fiber length showing high mean levels for both traits with high SCA effects and positive heterosis.