|Meredith Jr, William|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 25, 2010
Publication Date: November 15, 2010
Citation: Zeng, L., Meredith Jr, W.R. 2010. Germplasm potential for continuing improvement of fiber quality in upland cotton: combining ability for lint yield and fiber quality. Crop Science. 51:60-68. Interpretive Summary: There is a lack of high fiber quality in high yielding USA cotton cultivars, especially in the mid-south and southeastern regions. Cotton breeders are facing a challenge to improve fiber quality in order to meet standards in global market for raw fibers while maintaining lint yield for grower’s profits. Utilization of exotic germplasm in cotton breeding can broaden the genetic base of cotton cultivars and help breeders improve both lint yield and fiber quality. Regionally adapted exotic germlasm lines were crossed with cultivars in order to transfer desirable traits into these cultivars. Results suggest that selection for lint yield and fiber quality in crosses with these exotic germplasm lines will be effective in early generations of breeding. Best combiners for lint yield and fiber quality were identified from the exotic germplasm. These germplasm lines can be used as parents in breeding for improvement of lint yield and fiber quality.
Technical Abstract: Exotic germplasm can broaden the genetic base in upland cotton (Gossypium hirsutum L.) and help cotton breeders continue genetic improvement of lint yield and fiber quality in cultivars. The objectives of this study were to determine combining ability of exotic germplasm with cultivar and elite germplasm for lint yield and fiber properties, and identify parents from exotic germplasm for breeding. Twelve regionally adapted exotic germplasm lines were crossed with one cultivar and three elite germplasm lines in a North Carolina Design II scheme. The derived 48 F2 hybrids were evaluated at two locations with 4 and 3 replicates each in 2008 and 2009, respectively. Effects of general combining ability (GCA) was significant (P<0.001) for lint yield and all fiber properties. GCA effects were more important than specific combining ability (SCA) effects for all traits except elongation and 50% span length. Significant (P<0.05) favorable GCA effects were detected in all exotic germplasm parents for different fiber properties. JC60 was the best combiner among exotic lines with significant favorable GCA effects in most fiber properties. Significant positive GCA effects for lint yield and favorable GCA effects for at least one fiber property were detected in some exotic parents: SP156 and SP224 for lint yield and strength; SP192, SP205, and JC65 for lint yield, micronaire, and elongation; and SP192 and SP224 for lint yield and short fiber content and fineness, respectively. Significant (P<0.05) high-parent heterosis (HPH) for lint yield was detected in F2 hybrids of FM832 × SP205 (14%) and MD15 × SP205 (26%). These results provide evidence for the potential of these germplasm lines in breeding for continuing improvement of lint yield and fiber quality.