Source: Crop Science

Genetic Improvement of New Mexico Acala Cotton Germplasm and Their Genetic Diversity
J. F. Zhang^a, Y. Lu^a, H. Adragna^a and E. Hughs^b
a Dep. of Agronomy and Horticulture, Box 30003, New Mexico State Univ., Las Cruces, NM 88003
^b USDA-ARS, Southwestern Cotton Ginning Research Lab., Mesilla Park, NM 88003

ABSTRACT

The New Mexico cotton breeding program was established in 1926 and has been led by five generations of breeders and geneticists. The program has released more than 30 Acala 1517 cotton (Gossypium hirsutum L.) cultivars and numerous germplasm lines known for high fiber quality and Verticillium wilt (caused by Verticillium dahliae Kleb.) tolerance that have made substantial contributions to cotton breeding in the USA. The present project was initiated in 2003 to evaluate the genetic improvement of Acala 1517 cultivars and lines released over the past 75 yr in yield, boll size, seed index, lint percentage, fiber length, fiber strength, and micronaire. Their genetic divergence was also estimated by simple sequence repeat (SSR) markers. On the basis of the data available from annual yield trials, lint yield and lint percentage in Acala 1517 cotton have steadily increased since the 1930s, while boll size and seed index have gradually decreased 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 tended to shorten from 31.0 to 30.0 mm 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 30.5 mm. Genetic distance among Acala 1517 genotypes ranged from 0.06 to 0.38 with an average of 0.18 on the basis of 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.

Subscribers to Crop Science can access the complete article at http://crop.scijournals.org/cgi/content/full/45/6/2363.

21 December 2005

Improved New Mexico cotton assessed

Source: CropBiotech Update

The cotton breeding program for New Mexico's cultivars has hitherto led to the release of over 30 Acala 1517 cotton cultivars, and a variety of germplasm lines with high fiber quality and tolerance to Verticillium wilt. By analyzing “Genetic Improvement of New Mexico Acala Cotton Germplasm and Their Genetic Diversity,” J. F. Zhang of New Mexico State University and colleagues look at the products of the breeding program, and take a look at the cotton at both the molecular and macromolecular model.

By using such parameters as yield, boll size, and fiber strength; and measuring genetic divergence by molecular markers, researchers found, among others that: 1) lint yield and lint percentage have increased since the program's inception, while boll size and seed index have gradually decreased since the 1960s; 2) fiber strength has been enhanced, while fiber length has tended to shorten; and 3) there is substantial genetic diversity among the Acala 1517 cotton germplasm.

Researchers state that the Acala 1517 cultivars are “most genetically diverse from other current commercial cultivars and should be promising sources in breeding to be used as parental lines to broaden genetic variations within upland cotton.”