Data from: Genetic diversity of the two commercial tetraploid cotton species in the Gossypium Diversity Reference Set

A diversity reference set has been constructed for the Gossypium accessions in the U.S. National Cotton Germplasm Collection to facilitate more extensive evaluation and utilization of accessions held in the Collection. A set of 105 mapped simple sequence repeat markers were used to study the allelic diversity of 1,933 tetraploid Gossypium accessions representative of the range of diversity of the improved and wild accessions of G. hirsutum and G. barbadense. The reference set contained 410 G. barbadense accessions and 1,523 G. hirsutum accessions. Observed numbers of polymorphic and private bands indicated a greater diversity in G. hirsutum as compared to G. barbadense as well as in wild type accessions as compared to improved accessions in both species. The markers clearly differentiated the two species. Patterns of diversity within species were observed but not clearly delineated, with much overlap occurring between races and regions of origin for wild accessions and between historical and geographic breeding pools for cultivated accessions. Although the percentage of accessions showing introgression was higher among wild accessions than cultivars in both species, the average level of introgression within individual accessions, as indicated by species-specific bands, was much higher in wild accessions of G. hirsutum than in wild accessions of G. barbadense. The average level of introgression within individual accessions was higher in improved G. barbadense cultivars than in G. hirsutum cultivars. This molecular characterization reveals the levels and distributions of genetic diversity that will allow for better exploration and utilization of cotton genetic resources.

美国国家棉花种质资源库（U.S. National Cotton Germplasm Collection）针对库内保存的棉属（Gossypium）种质资源构建了一套多样性参考集，以推动该库内种质资源更全面的评价与利用。本研究采用105对已定位的简单序列重复（simple sequence repeat）标记，对1933份代表性四倍体棉属种质开展等位基因多样性分析，这些种质涵盖陆地棉（G. hirsutum）与海岛棉（G. barbadense）的栽培改良种质及野生种质的全部多样性谱系。该参考集包含410份海岛棉种质与1523份陆地棉种质。多态性条带与私有条带的观测数量显示，两个棉种中，陆地棉的多样性均高于海岛棉；野生种质的多样性也均高于栽培改良种质。所用标记可清晰区分两个棉种。虽可观测到种内多样性分布模式，但该模式并未得到清晰界定：野生种质的地理起源类群与原产地区间、栽培种质的历史育种群体与地理育种群体间均存在大量重叠。尽管两个棉种中，表现出基因渐渗的野生种质占比均高于栽培品种，但以物种特异性条带为参照时，陆地棉野生种质的单份种质平均渐渗水平显著高于海岛棉野生种质。海岛棉栽培改良品种的单份种质平均渐渗水平则高于陆地棉栽培品种。本分子表征研究明确了遗传多样性的水平与分布特征，可为棉花遗传资源的更高效挖掘与利用提供支撑。