Modulation of morphological and biochemical traits using heterosis breeding in coloured cotton

Heterosis breeding is a potential tool for developing coloured cotton hybrids, having good fibre yield and quality. The objective of the present study was to explore the extent of heterosis breeding for the modulation of fibre quality and biochemical traits during fibre development. The performance of 10 interspecific (Gossypium hirsutum L.×Gossypium barbadense L.) and four intraspecific (Gossypium hirsutum L.×Gossypium hirsutum L.) F1 coloured cotton hybrids and their parents was assessed under field conditions in 2008/9. Two interspecific, two intraspecific F1 coloured cotton hybrids and their parents were used to examine the role and changes in the amount of different biochemicals during the different stages of fibre development (2009). Among hybrids, interspecific brown cotton hybrids (ZUC × ZUA) and interspecific green cotton hybrids (ZUF × ZUA) showed high amounts of useful heterosis for yield, yield components and fibre quality attributes. Analysis of various biochemicals depicted a decline in fibre pH value and flavonoid contents among all hybrids and their parents, with maximum decrease in interspecific hybrids (ZUC × ZUA and ZUF × ZUA) at 15 days post anthesis (DPA). Similarly, a significant increase in the amount of cellulose, glucose and fructose was observed in all genotypes. However, the magnitude of increase was greatest in interspecific coloured cotton hybrids as compared to their parents and intraspecific hybrids. The negative correlation of fibre pH with flavonoid contents and the positive correlation of carbohydrates with cellulose contents (particularly at 15 DPA) suggested the significance of these biochemicals controlling fibre quality. In conclusion, heterosis breeding can be efficiently utilized to develop high-quality coloured cotton hybrids by modulating the synthesis of different biochemicals associated with fibre development and its quality.