Data from: Past and present dynamics of sorghum and pearl millet diversity in Mount Kenya region

Crop populations in smallholder farming systems are shaped by the interaction of biological, ecological and social processes, occurring on different spatiotemporal scales. Understanding these dynamics is fundamental for the conservation of crop genetic resources. In this paper we investigated the processes involved in sorghum and pearl millet diversity dynamics on Mount Kenya. Surveys were conducted in ten sites distributed along two elevation transects and occupied by six ethnolinguistic groups. Varieties of both species grown in each site were inventoried and characterized using SSR markers. Genetic diversity was analyzed using both individual and population based approaches. Surveys of seed lot sources allowed characterizing seed-mediated gene flow. Past sorghum diffusion dynamics were explored by comparing Mount Kenya sorghum diversity with that of the African continent. The absence of structure in pearl millet genetic diversity indicated common ancestry and/or important pollen and seed-mediated gene flow. On the contrary, sorghum varietal and genetic diversity showed geographic patterns, pointing to different ancestry of varieties, limited pollen-mediated gene flow, and geographic patterns in seed-mediated gene flow. Social and ecological processes involved in shaping seed-mediated gene flow are further discussed.

小农户耕作体系中的作物种群，由发生于不同时空尺度的生物、生态与社会过程共同塑造。明晰这些动态变化，对于作物遗传资源的保护而言至关重要。本研究针对肯尼亚山地区高粱与珍珠粟的多样性动态相关过程展开调查：沿两条海拔样带布设了10个调查样地，涉及6个民族语言群体；对每个样地种植的两个物种的品种进行了编目，并采用简单重复序列标记(SSR)进行特征分析；分别基于个体与种群层面的方法开展遗传多样性分析；通过对种子批次来源的调查，明确了种子介导的基因流特征；通过将肯尼亚山地区的高粱多样性与非洲大陆的高粱多样性进行对比，探究了历史上高粱的传播动态。研究结果显示，珍珠粟遗传多样性未呈现群体结构，表明其具有共同的祖先起源，或存在显著的花粉与种子介导的基因流；与此相反，高粱的品种与遗传多样性呈现地理分布模式，表明其品种起源各异、花粉介导的基因流有限，且种子介导的基因流存在地理分布特征。本研究进一步探讨了塑造种子介导基因流的社会与生态过程。