Cotton Breeding for Fiber Quality Improvement

Abstract

Cotton (Gossypium hirsutum L.) is the world’s leading fiber crop, grown or processed in many countries, providing a major contribution to their economies. Yield is economically most important to a producer which drives cultivar development and adoption; however, fiber quality is the primary focus for spinning mills. Cotton fiber quality must improve to remain competitive with synthetics due to increased demands for lightweight casual garments which require longer, stronger, and finer fibers. Improved cotton yields and fiber quality have continued to be realized through science-based plant breeding, particularly in countries and production systems with suitable climate and appropriate management inputs to maximize those improvements. The most significant challenge for cotton breeders has been to combine high yield with improved fiber quality, due to negative associations between yield and quality attributes in G. hirsutum. This chapter highlights practices to enable simultaneous improvement of yield and fiber quality during conventional breeding. There are adequate genetic resources available for innovative cotton breeders to make more progress, but new tools being offered by modern molecular technologies will achieve those gains more efficiently. Advances in fiber quality science have been made in cotton biotechnology – by improving our understanding of fiber development phases that contribute to fiber quality through gene discovery, genome mapping, and identification of linked molecular markers. Novel biotechnology traits have the potential to improve fiber yield and quality by altering the developmental phase associated with fibers per seed, fiber length, strength, and fineness. Biotechnology tools to facilitate improved conventional breeding through marker-assisted selection are also under development, particularly high-throughput techniques based on single nucleotide polymorphisms derived from next-generation sequencing. There are clearly great opportunities for better integration of conventional breeding and molecular biology, and as new GM traits are developed, a future challenge will be to combine multiple GM traits into elite cultivars. This could be assisted by the judicious use of molecular markers to herald a new age in cotton improvement. Cotton is one of the pioneer crops for the introduction of genetically modified (GM) insect and herbicide resistance, with about 80 % of global cotton being GM by 2012. That experience of research and deployment of these first-generation GM traits provides the foundation for development and exploitation of GM novel fiber property traits in the future.