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）构建了一套棉属种质多样性参考集，以更充分地开展对该库所保藏种质材料的评价与利用工作。研究团队采用105个已定位的简单序列重复（simple sequence repeat, SSR）标记，对1933份四倍体棉属种质材料的等位基因多样性展开分析，这些材料涵盖了陆地棉（G. hirsutum）与海岛棉（G. barbadense）的栽培品种及野生种质的全部多样性范围。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，陆地棉的遗传多样性高于海岛棉；且两个棉种的野生种质多样性均高于其栽培种质。该标记体系可清晰区分两个棉种。研究观察到种内的多样性分布模式，但未形成清晰的划分界限：野生种质的不同来源类群与原产地区域间存在大量遗传重叠，栽培种质的历史育种群体与地理育种群体间亦存在显著重叠。尽管两个棉种的野生种质的渐渗种质占比均高于栽培品种，但以物种特异性条带衡量的单份种质平均渐渗水平，陆地棉野生种质显著高于海岛棉野生种质。改良海岛棉栽培品种的单份种质平均渐渗水平，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，将为棉花遗传资源的深入挖掘与高效利用提供有力支撑。