Crop genetic diversity is a sine qua non for continuous progress in the development of improved varieties, hence the need for germplasm collection, conservation and characterization. Over the years, cowpea has contributed immensely to the nutrition and economic life of the people in Togo. However, the bulk of varieties grown by farmers are landraces due to the absence of any serious genetic improvement activity on cowpea in the country. In this study, the genetic diversity and population structure of 255 cowpea accessions collected from five administrative regions and the agricultural research institute of Togo were assessed using 4600 informative diversity array technology (DArT) markers. Among the regions, the polymorphic information content (PIC) ranged from 0.19 to 0.27 with a mean value of 0.25. The expected heterozygosity (He) varied from 0.22 to 0.34 with a mean value of 0.31, while the observed heterozygosity (Ho) varied from 0.03 to 0.07 with an average of 0.05. The average inbreeding coefficient (F_IS) varied from 0.78 to 0.89 with a mean value of 0.83, suggesting that most of the accessions are inbred. Cluster analysis and population structure identified four groups with each comprising accessions from the six different sources. Weak to moderate differentiation was observed among the populations with a genetic differentiation index varying from 0.014 to 0.117. Variation was highest (78%) among accessions within populations and lowest between populations (7%). These results revealed a moderate level of diversity among the Togo cowpea germplasm. The findings of this study constitute a foundation for genetic improvement of cowpea in Togo.

中文翻译：

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基于DArT标记的多哥豇豆[Vigna unguiculata (L.) Walp.]种质遗传多样性和种群结构

作物遗传多样性是改良品种开发不断取得进展的必要条件，因此需要种质收集、保存和鉴定。多年来，豇豆为多哥人民的营养和经济生活做出了巨大贡献。然而，由于该国缺乏任何认真的豇豆遗传改良活动，农民种植的大部分品种都是地方品种。在这项研究中，使用4600个信息多样性阵列技术（DArT）标记对从多哥五个行政区和农业研究所采集的255个豇豆种质的遗传多样性和种群结构进行了评估。其中，多态信息含量（PIC）范围为0.19至0.27，平均值为0.25。预期杂合度（He）从 0.22 到 0.34 变化，平均值为 0.31，而观察杂合度（Ho）从 0.03 到 0.07 变化，平均值为 0.05。平均近交系数(F _IS )从0.78到0.89变化，平均值为0.83，表明大多数种质是近交系。聚类分析和种群结构确定了四个组，每个组包含来自六个不同来源的种质。在遗传分化指数为0.014至0.117的群体中观察到弱至中度分化。种群内种质间的变异最高（78%），种群间变异最低（7%）。这些结果表明多哥豇豆种质具有中等水平的多样性。这项研究的结果为多哥豇豆遗传改良奠定了基础。