Data from: Genetic diversity of oilseed rape fields and feral populations in the context of coexistence with GM crops

Despite growing concern about transgenes escaping from fields, few studies have analysed the genetic diversity of crops in an agroecosystem over several years. Accurate information about the dynamics and relationship of the genetic diversity of crops in an agroecosystem is essential for risk assessment and policies concerning the containment of genetically modified crops and their coexistence with crops grown by conventional practices. Here, we analysed the genetic diversity of oilseed rape plants from fields and feral populations over 4 years in an agricultural landscape of 41 km2. We used exact compatibility and maximum likelihood assignment methods to assign these plants to cultivars. Even pure lines and hybrid cultivar seed lots contained several genotypes. The cultivar diversity in fields reflected the conventional view of agroecosystems quite well: that is, there was a succession of cultivars, some grown for longer than others because of their good performance, some used for one year and then abandoned, and others gradually adopted. Three types of field emerged: fields sown with a single cultivar, fields sown with two cultivars, and unassigned fields (too many cultivars or unassigned plants to reliably assign the field). Field plant diversity was higher than expected, indicating the persistence of cultivars that were grown for only one year. The cultivar composition of feral populations was similar to that of field plants, with an increasing number of cultivars each year. By using genetic tools, we found a link between the cultivars of field plants in a particular year and the cultivars of feral population plants in the following year. Feral populations on road verges were more diverse than those on path verges. All of these findings are discussed in terms of their consequences in the context of coexistence with genetically modified crops.

尽管学界对转基因（transgenes）从田间逃逸的担忧与日俱增，但目前鲜有研究在多年尺度下分析农业生态系统（agroecosystem）中作物的遗传多样性。精准掌握农业生态系统中作物遗传多样性的动态与关联信息，对于转基因作物（genetically modified crops）的风险评估、管控政策，以及其与常规种植作物的共存管理至关重要。本研究针对面积41 km²的农业景观中，来自田间与野生种群（feral populations）的油菜（oilseed rape）植株展开了为期4年的遗传多样性分析。本研究采用精确相容性分析法（exact compatibility）与最大似然归属法（maximum likelihood assignment），将受试植株归属至相应品种（cultivar）。即便纯系品种与杂交品种的种子批次中，亦存在多种基因型（genotypes）。田间的品种多样性较好地契合了学界对农业生态系统的传统认知：即品种存在更替现象——部分品种因表现优异得以长期种植，部分仅种植一年便被弃用，另有一些则逐步得到推广。研究共识别出三类田块：单品种播种田块、双品种播种田块，以及无法归属的田块（因品种过多或植株无法可靠归属）。田间植株的遗传多样性超出预期，表明仅种植一年的品种仍得以存续。野生种群的品种组成与田间植株相似，且每年的品种数量均呈上升趋势。借助遗传分析工具，本研究发现某一年份田间植株的品种，与次年野生种群植株的品种之间存在关联。路肩（road verges）处的野生种群遗传多样性高于步道边缘（path verges）的野生种群。本研究就上述所有发现，结合转基因作物共存的相关背景，探讨了其潜在影响与意义。