Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: January 9, 2014
Publication Date: July 24, 2014
Citation: Zeng, L. 2014. Broadening the genetic base of upland cotton in U.S. cultivars: genetics variation for lint yield and fiber quality in germplasm resources. Book Chapter. 231-246, ISBN 978-953-51-1622-6. Technical Abstract: Genetic improvement of both lint yield and fiber quality is a challenge to cotton breeders because of the negative associations between lint yield and fiber quality. The limited success in the breakup of unfavorable associations in breeding might be a result of the narrow genetic base in Upland cotton cultivars. Introgression of exotic germplasm into Upland cotton cultivars is an effective approach to broaden the genetic base and increase the chance to break or reduce unfavorable associations. An overview of genetic diversity in a few germplasm populations with exotic germplasm backgrounds developed by some public breeding programs in the U.S are presented in this chapter. Significant genetic variations for lint yield and fiber properties have been identified in previous evaluation of these germplasm populations. Characterization of these germplasm populations based on molecular markers showed great genetic distance within germplasm populations and also wide genetic distance from commercial Upland cotton cultivars. These results indicate that genetic diversity is maintained in these germplasm and they can continue to serve as gene pools for introgression breeding. Some germplasm lines were detected with desirable combinations between lint yield and one or a few fiber properties in previous breeding using different germplasm resources. Diverse genetic associations including favorable and unfavorable ones between yield traits and fiber properties were identified in different germplasm populations. These results indicate that introgression of novel genes from exotic germplasm resources into Upland cotton cultivars is necessary for broadening its genetic base and increasing success in the breakup or reduction of unfavorable associations between lint yield and fiber quality.