While climate change mainly applies to global warming and subsequent drought periods, freezing periods also are changing and may trigger genetic adaptation. However, there are few prospective, experimental demonstrations. This paper investigates how effectively genetic frost-resistant variants can respond differently to frost periods, especially in farmers’ fields where various other selection pressures occur. An experiment using Avena fatua variants was set up in the field over 8 years of winter crop rotation. The frequency of each variant identified by their leaf isozymes was estimated every year. Six years were necessary to observe a weak trend towards an increased frequency of the frost-resistant phenotype, while the other variants had apparent erratic behaviour. Selection of the frost-resistant variant was challenged by irregular low temperature selection pressure, differential dormancy, germination and seed production, and possibly herbicide sensitivity that mitigated the expression of the selection response. This experiment shows how plant polymorphism and farmers’ practices that superimpose habitat unpredictability diversify possible responses to selection pressures and delay adaptation. However, if climate change brings both higher mean temperatures and extreme values, changes of apparent plant phenology could happen for weeds species displaying the appropriate genetic variability within the time-frame of farmers’ career, thus necessitating correlative adaptation of farming practices.

中文翻译：

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Avena fatua 抗冻变种的相对成功：田间试验

虽然气候变化主要适用于全球变暖和随后的干旱期，但冰冻期也在发生变化，并可能引发基因适应。但是，很少有前瞻性的实验性演示。本文研究了基因抗霜冻变异如何有效地对霜冻期做出不同的反应，特别是在发生各种其他选择压力的农田中。一个实验使用燕麦经过 8 年的冬季轮作，在田间建立了变种。每年估计由其叶同工酶鉴定的每种变体的频率。需要六年的时间才能观察到抗冻表型频率增加的微弱趋势，而其他变体具有明显的不稳定行为。抗冻变体的选择受到不规则低温选择压力、差异休眠、发芽和种子生产以及可能减轻选择反应表达的除草剂敏感性的挑战。该实验展示了植物多态性和农民的实践如何叠加栖息地的不可预测性，从而使对选择压力和延迟适应的可能反应多样化。然而，如果气候变化带来更高的平均温度和极端值，