Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 12, 2010
Publication Date: April 1, 2011
Citation: Hinze, L.L., Kohel, R.J., Campbell, B.T., Percy, R.G. 2011. Variability in four diverse cotton (Gossypium hirsutum L.) germplasm populations. Genetic Resources and Crop Evolution. 58(4):561-570. Interpretive Summary: There is a need to improve the agronomics and fiber quality of cotton to meet changing environmental challenges and global market standards. Resources that are available for cotton improvement in the U.S. Cotton Germplasm Collection and public breeding programs often are under-utilized because they are poorly adapted to specific environments or occur in poor agronomic backgrounds. To make variability for desirable agronomic and fiber traits more available, four genetically diverse breeding populations have been created using random mating of multiple parents of divergent morphology, physiology, and adaptation. Analyses of agronomic and fiber properties of the four diverse cotton populations demonstrate that the development of diverse, multiple-parent populations is a beneficial and efficient means of creating and identifying useful variability. Use of these and similar populations will allow breeders to more fully utilize resources available in the U.S. Cotton Germplasm Collection and diverse public breeding programs to improve cultivated cotton grown in the United States.
Technical Abstract: A broad range of cotton (Gossypium hirsutum L.) germplasm resources exist with characteristics useful for improving modern cotton cultivars. However, much of this germplasm is not well utilized. The objective of this study was to evaluate agronomic and fiber traits of four germplasm populations to determine the effectiveness of pooling germplasm for generating variability to improve traits of interest. Four populations were developed with parents chosen based on 1) dwarfing genes, 2) a combination of fiber strength and length traits, 3) glandless genes, or 4) inclusion in the G. hirsutum center-of-origin, i.e. race, germplasm group. The dwarf germplasm population had smaller bolls, a smaller lint index, a smaller seed index, lower micronaire, and shorter fibers than the other three populations. There were no significant differences in lint yield, elongation, or strength among the germplasm populations. In contrast to the general lack of significant differences among populations for agronomic and fiber traits, within population variation was observed to be high. Therefore, selection could be made within the race population to raise lint yields and within the fiber population to increase fiber length. Likewise, selections within the glandless population could be made for boll size, lint index, seed index, micronaire, and strength. These results suggest that hybridizing multiple parents in complex populations generates a large amount of variability with potential uses in crop improvement.