Studies on Combining Ability and Heterosis through Diallel Analysis in Cotton (Gossypium hirsutum L.)

Abstract

Aim: The study aimed to investigate the genetic mechanisms influencing yield and fibre quality traits in cotton (Gossypium hirsutum L.) using a diallel mating system, and to identify superior hybrids with potential for cotton breeding programmes. Study Design: The study was based on a full diallel mating design involving seven parental genotypes and their hybrids. Place and Duration of Study: The field experiment was conducted at the Department of Genetics and Plant Breeding, Annamalai University, Tamil Nadu, India, over two consecutive growing seasons from 2021 to 2023. Methodology: A total of 42 hybrids were developed through a diallel mating system using seven genetically diverse cotton genotypes, along with a standard check variety, Suraksha. The genotypes were evaluated in a randomized complete block design (RCBD) with three replications. Data were recorded on key yield attributes and fibre quality parameters. General Combining Ability (GCA), Specific Combining Ability (SCA), and heterosis analysis were conducted to identify superior parental combinations. Results: Significant genetic variability was observed among parents and hybrids for all studied traits. The hybrids Subiksha × Anjali, Anjali × Suraksha, Suraksha × Sunantha, and LRA 5166 × Sunantha exhibited high SCA effects and better heterotic performance for yield and fibre quality traits. These combinations also showed promising potential in terms of boll number, boll weight, lint index, fibre length, strength, and micronaire values. The analysis indicated both additive and non-additive gene actions influencing the traits. Conclusion: The identified hybrids showed superior performance and possess desirable genetic potential for yield and fibre quality improvement. These results provide valuable insights for future cotton breeding programmes aiming to develop high-yielding, quality fibre cultivars.