B. T. Campbell

Status of the USA cotton germplasm collection and crop vulnerability.

The National Plant Germplasm System (NPGS) is a cooperative effort among State, Federal and Private organizations aimed at preserving one of agriculture’s greatest assets: plant genetic diversity. The NPGS serves the scientific community by collecting, storing, and distributing germplasm as well as maintaining a searchable database of trait descriptors. Serving the NPGS, a Crop Germplasm Committee (CGC) is elected for each crop and is comprised of a group of scientists concerned with development, maintenance, characterization, and utilization of germplasm collections. Each CGC serves in an advisory role and provides a status report every seven years to determine scientific efforts, adequacy of germplasm base representation, and progress in breeding through utilization of germplasm. In addition, each committee can call attention to areas of concerns regarding facilities and staffing associated with the maintenance, collection, and taxonomic activities for a specific crop within the system. The following report was developed by the CGC for cotton and provides a record of collections, activities, concerns, crop vulnerabilities, and recommendations associated with the cotton collection for the period 1997–2005. Information provided within this document is a much expanded and detailed description of a report provided to the NPGS and includes the most exhaustive citation of germplasm depositions and research activity descriptions available anywhere in the USA for this time period. This documentation will be a valuable resource to breeders, geneticists, and taxonomists with an interest in this important food and fiber crop.

Chromosome Substitution Lines: Concept, Development and Utilization in the Genetic Improvement of Upland Cotton

Cotton is the most important natural fiber source for the textile industry world-wide. It is also an alternative of the man-made petroleum-based “synthetic fibers” providing an advantage for a sustainable environment. Cotton is formed by developing seed of several Gossypium species, which are mainly grown as an important cash crop in more than 70 countries including USA, India, China and Uzbekistan (Smith and Coyle, 1997). Although cotton plants are best known as the renewable source of textile materials for clothing, the fiber, seed and plants have many other uses, including home insulation to save energy, protein-rich seedderived feed for animals, cottonseed oil as a foodstuff for humans, and as a source of mulch and biomass (Cotton Incorporated, 2010, http://cottontoday.cottoninc.com/sustainabilityabout/responsible-economic-development, verified on October 14, 2011). This brings significant humanitarian and economic benefits. For example, scientists are exploring genetic means to better harness its highly nutritious seed for food and feed (Sunilkumar et al., 2006).

Assessing the breeding potential of day-neutral converted racestock germplasm in the Pee Dee cotton germplasm enhancement program

The primitive, upland cotton landrace collection represents one of the untapped genetic resources in cotton breeding programs. Efforts to utilize these resources have been slow, but the development of day-neutral converted germplasm lines offers tremendous potential for broadening the genetic base in upland cotton. Using topcross hybrids involving elite germplasm from the unique Pee Dee germplasm enhancement program, we evaluated the breeding potential of a select number of day-neutral converted racestocks. The mean performance of parental lines and F2 topcross hybrids along with genetic effect estimates indicate that day-neutral converted germplasm lines decreased agronomic performance while increasing fiber quality performance. Results suggest that crosses between day-neutral converted racestocks and elite Pee Dee germplasm lines result in new allelic combinations associated with improved fiber quality performance that interact in a non-additive way. However, it appears that converted racestocks transmit negatively correlated alleles for agronomic performance and fiber quality. These negatively correlated allelic combinations present a major challenge for cotton breeding programs. Future efforts that incorporate DNA based selection methods to identify and fix introgressed segments from converted racestocks and their offspring should enhance the use of the genetic variation present in the primitive racestock germplasm accessions.

Improving the Precision of NDVI Estimates in Upland Cotton Field Trials

Estimates of NDVI in upland cotton were influenced by field heterogeneity. Row–column design and spatial analysis improved the precision of NDVI estimates. Extensive rank changes in genotype mean estimates were observed across models.