Data from: Genetic diversity and structure of Lolium perenne ssp. multiflorum in California vineyards and orchards indicates potential for spread of herbicide resistance via gene flow

Management of agroecosystems with herbicides imposes strong selection pressures on weedy plants leading to the evolution of resistance against those herbicides. Resistance to glyphosate in populations of Lolium perenne L. ssp. multiflorum is increasingly common in California, USA, causing economic losses and the loss of effective management tools. To gain insights into the recent evolution of glyphosate resistance in L. perenne in perennial cropping systems of northwest California and to inform management, we investigated the frequency of glyphosate resistance and the genetic diversity and structure of 14 populations. The sampled populations contained frequencies of resistant plants ranging from 10% to 89%. Analyses of neutral genetic variation using microsatellite markers indicated very high genetic diversity within all populations regardless of resistance frequency. Genetic variation was distributed predominantly among individuals within populations rather than among populations or sampled counties, as would be expected for a wide-ranging outcrossing weed species. Bayesian clustering analysis provided evidence of population structuring with extensive admixture between two genetic clusters or gene pools. High genetic diversity and admixture, and low differentiation between populations, strongly suggests the potential for spread of resistance through gene flow and the need for management that limits seed and pollen dispersal in L. perenne.

施用除草剂进行农业生态系统管理会对杂草类植物施加强烈的选择压力，进而促使其演化出针对此类除草剂的抗药性。在美国加利福尼亚州，多花黑麦草（Lolium perenne L. ssp. multiflorum）种群对草甘膦的抗药性案例日益普遍，这不仅造成了经济损失，还导致有效田间管理手段的失效。为深入解析美国加州西北部多年生种植系统中多花黑麦草抗草甘膦特性的近期演化机制，并为其科学管理提供依据，我们针对14个种群的草甘膦抗药性频率、遗传多样性及种群遗传结构开展了调查研究。采样种群中的抗性植株占比介于10%至89%之间。利用微卫星标记对中性遗传变异进行分析的结果显示，无论抗药性频率高低，所有种群内部均具有极高的遗传多样性。遗传变异主要分布于种群内部的个体之间，而非种群间或采样县域间，这与广布异交杂草物种的预期遗传分布模式一致。贝叶斯聚类分析结果表明，该物种存在种群遗传结构特征，且两个遗传簇或基因库之间存在广泛的遗传混合现象。较高的遗传多样性与遗传混合程度，加之种群间较低的遗传分化程度，均强烈暗示抗药性性状可通过基因流快速扩散，因此亟需制定能够限制多花黑麦草种子与花粉传播的管控策略。