1a. Objectives (from AD-416):
Develop Upland cotton breeding populations using near-extra-long staple (ELS) germplasm.
1b. Approach (from AD-416):
In 2008, thirteen near-extra-long staple (ELS) accessions were obtained from the USDA-ARS National Cotton Collection in College Station, Texas. Over two years, these accessions were grown in the field, self-pollinated, purified, and seed increased. Eleven of the near-ELS accessions were confirmed to possess near-ELS fiber properties and will be used in two mating schemes to generate segregating breeding populations. In 2011, the eleven near-ELS accessions were each crossed to 5-6 elite Upland cotton germplasm lines using a topcross mating design. In September 2011, the resulting F1 crosses were sent to the Cotton Winter Nursery for seed increase. In 2012, the F2 hybrids and parental lines will be evaluated in replicated trials in 1-3 environments across South Carolina and North Carolina depending on seed availability. Yield and yield component data will be collected. Prior to harvest, a boll sample will be hand harvested and used to calculate lint percent and yield components. The boll sample will also provide a fiber sample for measuring HVI fiber properties. Using an additive-dominance mixed model, variance components and estimates of general and specific combining ability will be calculated for each cross combination. Seed from selected families will be advanced and integrated into the progeny row nursery of the breeding program. Also in 2012, a half-diallel mating scheme will be initiated among the same eleven near-ELS accessions. F1 crosses will be increased at the Cotton Winter Nursery. In 2013, the F2 hybrids and parental lines will be evaluated in replicated trials in 1-3 environments across South Carolina and North Carolina depending on seed availability. Yield, yield components, and HVI fiber properties will be collected and statistically analyzed. Analyses will focus primarily on determining the extent of genetic variation for fiber properties among near-ELS x near-ELS matings. Seed from selected near-ELS x near-ELS families will be advanced and integrated into the progeny row nursery of the breeding program.
3. Progress Report:
This project is related to objective 2 of the in-house project: to develop new cotton genetic resources with improved fiber quality, lint yield stability, and adaptation. To meet current and perceived future demands, cotton breeding programs must increase fiber quality potential and provide this potential to growers via new, high quality cultivars. The primary objective of this cooperative research project is to develop breeding populations derived from high fiber quality near-ELS (extra long staple) germplasm. Eleven near-ELS upland cotton accessions were selected after confirming high fiber quality and were each crossed to six elite upland cotton germplasm lines using a topcross mating design. In total, each cross combination was seed increased at the Cotton Winter Nursery in Mexico. The F2 hybrids and parental lines are currently being field evaluated in a three replicate yield trial in South Carolina. At season’s end, agronomic and fiber quality data will be collected and used in an analysis to determine the combining ability or breeding potential associated with each near-ELS accession. Following the collection of agronomic and fiber quality data from additional replicated trials, information will be provided to the cotton breeding community on the feasibility of using near-ELS germplasm in order to develop new, high yield and quality cultivars that meet international market demands.