Phelipanche ramosa (Branched broomrape) is an obligate root parasitic plant that is a major pest of oilseed rape in France. Knowledge on seed viability and dormancy under field conditions is crucial to understand how to control P. ramosa, but is as yet unknown. Our study aimed to quantify these processes with a 2‐year seed burial experiment. Two genetically distinct populations of P. ramosa were studied, collected on winter oilseed rape (population O) and hemp (population H). Seed mortality was very low in both populations (4–7% per year). Although obligate parasitic seeds are assumed to germinate only after exposure to germination stimulants from host root exudates, a high proportion of population H seeds germinated spontaneously (up to 90%). Seeds of both populations displayed seasonal dormancy, with timing and magnitude depending on the population. Dormancy was low at the time each native host crop is usually sown. Populations differed in germination dynamics, with seeds of population H germinating faster. The difference in behaviour that we observed between populations is consistent with reported adaptations of pathovars to their preferred hosts. The results indicate that the parasitic plant management requires targeting at the populations concerned. For example, delayed sowing is more promising against population O than against population H.

中文翻译：

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兰竹种子休眠和死亡的种内季节变化

Phelipanche ramosa（分支的room帚）是专性的根寄生植物，是法国油菜的主要害虫。关于田间条件下种子生存力和休眠的知识对于了解如何控制裸果假单胞菌至关重要，但目前还未知。我们的研究旨在通过2年的种子埋葬实验来量化这些过程。ramosa的两个遗传上不同的种群进行了研究，收集了冬季油料油菜（种群O）和大麻（种群H）。两种种群的种子死亡率都很低（每年4-7％）。尽管假定专性寄生种子仅在暴露于宿主根分泌物的发芽刺激剂后才能发芽，但仍有很大比例的H族种子自发发芽（高达90％）。两种种群的种子均显示季节性休眠，时间和大小取决于种群。通常在每种本地寄主作物播种时休眠率很低。种群的萌发动态不同，种群H的种子发芽更快。我们在人群之间观察到的行为差异与报道的病原菌适应其偏好宿主的报道一致。结果表明，寄生植物管理需要针对相关人群。例如，延迟播种对种群O的抗性比对种群H的更有希望。