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.针对美国国家棉花种质资源库（U.S. National Cotton Germplasm Collection）内的棉属种质材料（Gossypium accessions）构建了一套多样性参考集，以更全面地评估和利用该库所保存的种质资源。本研究采用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进行等位基因多样性分析，这些材料涵盖了陆地棉（G. hirsutum）和海岛棉（G. barbadense）的栽培改良种质与野生种质的多样性范围。该参考集包含410份海岛棉种质与1523份陆地棉种质。通过统计多态性条带与私有条带的数量，结果显示：相较于海岛棉，陆地棉的遗传多样性更为丰富；同时在两个棉种中，野生种质的遗传多样性均高于栽培改良种质。该套标记可清晰区分两个棉种。虽可观测到棉种内的多样性分布模式，但并未得到清晰界定：野生种质的生态型与起源区域之间、栽培种质的历史育种群体与地理育种群体之间均存在大量重叠。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，但基于物种特异性条带分析的结果显示：陆地棉野生种质的平均个体渐渗水平远高于海岛棉野生种质。而在栽培改良种质中，海岛棉品种的平均个体渐渗水平高于陆地棉品种。本分子表征分析明确了遗传多样性的水平与分布特征，将有助于更高效地挖掘和利用棉花遗传资源。