Working group session:
Germplasm and Genetic Stocks
Presentation type:
oral
Authors:
Fang, David; Hinze, Lori; Percy, Richard; Li, Ping
Presenter:
Fang, David
Correspondent:
Fang, David
Abstract:
Cultivated Upland cotton (Gossypium hirsutum) has very low genetic diversity. Therefore, to differentiate closely-related cotton cultivars or to conduct a genome-wide association-based molecular breeding project requires a large number of polymorphic markers with good genome coverage. In this study, 1555 mapped simple sequence repeat (SSR) markers were screened for their polymorphisms within elite Upland cotton. Out of 925 polymorphic markers, 448 were selected to form the highly informative marker set. Seventy-five multiplex PCR bins were designed to amplify these markers. The 448 markers were used to genotype 193 elite Upland cotton cultivars from 26 countries. These markers revealed 1590 alleles belonging to 732 loci that covered the genome. The average polymorphism information content of the polymorphic loci was 0.287, and all sampled cultivars could be differentiated using this set of markers. Intra-cultivar polymorphism was mainly due to heterogeneity and present in most cultivars. No clear population structure was observed among the sampled cultivars, an indication that very few contributing ancestors were involved in the creation of modern Upland cotton cultivars around the world and that extensive blending of the variability present had occurred. However, some grouping was possible; allowing the sampled cultivars to be classified into nine groups. Clustering results were largely congruent with the breeding history and pedigrees of the cultivars. The marker set developed here along with their profiles in elite Upland cotton will provide cotton scientists with very useful information and efficient tools in their genetic and breeding studies.