Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/16/2005
Publication Date: 1/17/2005
Citation: Zhang, J., Lu, Y., Adranga, H., Hughs, S.E., Cantrell, R.G. 2005. Genetic improvement of New Mexico ACALA cotton germplasm and their genetic divergence. In: Proceedings of the Beltwide Cotton Conference, January 4-7, 2005, New Orleans, Louisiana. p. 886-891. 2005 CDROM. Interpretive Summary: New Mexico State University has released more than 30 Acala 1517 cotton varieties since the start of its cotton breeding program in 1926. A project was initiated in 2003 to evaluate what Acala 1517 traits were improved over the past 79 years and if there was genetic potential for significant future improvement from existing Acala 1517 germplasm. Fiber yield has been one factor that has steadily improved over the breeding program with accelerated yield improvement during the past 20 years. Fiber strength is another Acala 1517 quality factor that has been increased during the ensuing years. The potential for future gains in these as well as other Acala 1517 quality traits was investigated by a technique known as simple sequence repeat (SSR) markers. SSR data indicated that current Acala 1517 cultivars have the genetic potential for significant future increases in yield and fiber quality as well as increased resistance to plant diseases such as verticillium wilt. These Acala cultivars also have the potential for being part of upland cotton breeding improvements across the U.S. cotton belt.
Technical Abstract: The New Mexico cotton breeding program was established in 1926 and has been led by five generations of breeders and geneticists (G. N. Stroman, G. Staten, D. Davis/N. Maim, R. G. Cantrell, and Jinfa Zhang). The program has released more than 30 Acala 1517 cotton cultivars (Table 1) and numerous germplasm lines known for high fiber quality and Verticillium wilt tolerance. The present project was initiated in 2003 to evaluate the genetic improvement of Acala 1517 cultivars and lines released over the past 75 years in yield, boll size, seed index, lint percentage, fiber length, fiber strength, and micronaire. Their genetic divergence was also estimated using simple sequence repeat (SSR) markers. Based on the data available from annual yield trials, lint yield and lint percentage in Acala 1517 cotton have been steadily increased since 1930-1940, while boll size and seed index have been gradually reduced since the 1960s. Fiber strength has been enhanced since the 1960s, which has been accompanied by steady increase in micronaire. However, fiber length in Acala 1517 cultivars was seen a tendency of reduction from 1.22 to 1.18 inch from 1960 to 1990, whereas newly released Acala 1517 cultivars (Acala 1517-95, 1517-99, 1517-02, 1517-03, and 1517-04) have fiber greater than 1.20 inch. Genetic distance among Acala 1517 genotypes ranged from 0.06 to 0.38 with an average of 0.18 based on 189 SSR marker alleles, indicating a substantial genetic diversity among Acala 1517 cotton germplasm. Divergent germplasm introgression in the program has contributed to genetic diversity of Acala cotton germplasm and continuous genetic gain in Acala cotton cultivar improvement.