Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/17/2009
Publication Date: 12/15/2009
Citation: Ulloa, M., Percy, R.G., Hutmacher, R.B., Zhang, J. 2009. The Future of Cotton Breeding in the Western United States. J. Cotton Sci. 13(4):246-255. Interpretive Summary: Increasing productivity and reducing production costs are significant goals to cotton growers. Fiber quality is also a consideration because of its large impact on overall profitability. Relatively stagnant or even declining cotton prices in recent decades have played an important role in highlighting that growers need higher production and/or reduced input costs to generate acceptable profits. In the coming decade, the high priority breeding objectives for production regions of the western U.S. (far-western Texas, New Mexico, Arizona, and California) will involve complex traits such as yield, fiber quality, and resistance to diseases and insect pests. All of these traits are controlled by many interacting genes. In addition, plant characteristics that improve water-use efficiency, heat tolerance, and cotton fiber uniformity will become increasingly important to the cotton industry. In this manuscript we provide a brief overview of the history, direction, and future of cotton breeding in the Western United States. Although considerable progress in breeding for yield, fiber quality, and disease and pest resistance has occurred in the last 70 years, plant biotechnology, such as transgenic varieties, will offer additional solutions by minimizing the damage from insects and weed pests, minimizing chemical inputs, and protecting the environment. In addition, continuing progress made in genomics research such as developing molecular markers, genetic mapping, and gene expression, should help growers and the industry. This research area will eventually provide molecular markers that will be incorporated into breeding programs to speed efforts to develop a wide variety of improved cultivars.
Technical Abstract: Traditional breeding efforts dramatically transformed the cotton (Gossypium spp.) plant during the last century. In the coming decade, the high priority breeding objectives for production regions of the western U.S. (far-western Texas, New Mexico, Arizona, and California) will involve morphologically complex traits controlled by many interacting genes. While perennial concerns regarding yield, response to pests (lygus, thrips, aphids, and whitefly), and disease resistance (seedling fungal diseases, Fusarium and Verticillum wilts, and root-knot nematode: disease associations) remain, plant characteristics conferring improved water-use efficiency, heat tolerance, and fiber quality and uniformity will become increasingly important to the cotton industry. With the rapid changes in cotton acreage, production practices, and markets, growers and breeders continue to face many challenges. In New Mexico, adoption of transgenic cotton in the early 2000’s resulted in decreased planting of conventional Acala 1517 varieties, which declined to about 5% of total cotton acreage by 2005. However, Bt transgenic Acala 1517 became available in 2006 and planting of that variety increased to 14% of total acreage in that same year. In Arizona, improvements in productivity and fiber quality in American Pima (G. barbadense L.) were made possible by emphasizing selection for adaptation to high temperature environments. However, yield losses caused by heat stress continue to be significant in Upland, Pima and Acala cottons, averaging about 12% annually in Arizona alone. Further improvements will require the development of better selection tools for heat tolerance. In California, Fusarium wilt race 4 currently poses new challenges, making breeding for resistance against this pathogen a priority. With cotton acres declining in the western production regions from approximately 2 million in the 1970s to less than 700,000 today, and a continuing shift in production from Acala to Pima, sustainability of the industry will likely require that breeders emphasize high yields, reduced production inputs, and lint characteristics that attract premium prices.