Thursday, June 23, 2011

Cotton Breeding Litmus Test

Like many globally important agricultural commodities, continued genetic improvement of cotton (Gossypium spp.) is essential to increase the quantity and quality of cotton production systems. Over the last 10-15 years, the globalization of cotton textile manufacturing and the adoption of high-speed fiber spinning machinery have increased the global demand for high quality fiber. Hence, increasing pressure is being placed on cotton breeding programs to increase yields while simultaneously increasing fiber quality. Assessing the progress of breeding methods used in the past is a first step to designing effective cotton breeding strategies to meet current and future global demands.
Scientists with the U.S. Department of Agriculture’s Agricultural Research Service (USDA-ARS) led a team that included the University of Georgia, N.C. State University, Dow Agrosciences, and Monsanto Company, in a project funded by the U.S. Department of Agriculture and Cotton Incorporated, to determine the genetic improvement of the USDA-ARS Pee Dee cotton germplasm program following 70 years of cotton breeding. Historically, the Pee Dee program has provided the cotton industry elite fiber quality germplasm and was developed using a unique, genetic foundation of germplasm from Upland (G. hirsutum L.), Sea Island (G. barbadense L.), and primitive diploid cottons. Results from the study were published in the May-June issue of Crop Science.
Eighty-two released germplasm lines and cultivars developed since 1935 were selected based upon breeding history and separated into eight groups according to their breeding cycle. In addition to current commercial cultivars, the 82 Pee Dee germplasm lines and cultivars were evaluated for agronomic and fiber quality performance in 14 southeastern U.S. production environments over a three year period. The extensive agronomic and fiber quality performance dataset was used to estimate genetic improvement within the Pee Dee germplasm program over time.
Results suggest that genetic improvement of agronomic traits has steadily increased approximately 3% per breeding cycle. At the same time, fiber quality performance decreased less than 1% per breeding cycle. Taken together, these results suggest that the well-known, negative relationship between lint yield and fiber quality properties has been minimized by the various breeding methods employed over 70 years of plant breeding. These results also provide evidence that genetic recombination-based breeding methods should continue creating rare individuals representing a break in the negative linkage between lint yield and fiber quality properties.
This 70-year litmus test on the USDA-ARS Pee Dee cotton germplasm program suggests that sufficient genetic variation remains to simultaneously improve agronomic and fiber quality performance. Research is ongoing at USDA-ARS to develop elite cotton germplasm with the combination of high lint yield and high fiber quality performance. Considering the diverse foundation of the Pee Dee germplasm program, future research should determine the origin of the beneficial fiber quality alleles present in the Pee Dee germplasm collection.

Story Source:
Crop Science Society of America /

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