Data from: An examination of fitness costs of glyphosate resistance in the common morning glory, Ipomoea purpurea

Fitness costs are frequently invoked to explain the presence of genetic variation underlying plant defense across many types of damaging agents. Despite the expectation that costs of resistance are prevalent, however, they have been difficult to detect in nature. To examine the potential that resistance confers a fitness cost, we examined the survival and fitness of genetic lines of the common morning glory, Ipomoea purpurea, that diverged in the level of resistance to the herbicide glyphosate. We planted a large field experiment and assessed survival following herbicide application as well as fitness of the divergent selection lines in the absence of the herbicide. We found that genetic lines selected for increased resistance exhibited lower death compared to control and susceptible lines in the presence of the herbicide, but no evidence that resistant lines produced fewer seeds in the absence of herbicide. However, susceptible lines produced more viable seeds than resistant or control lines, providing some evidence of a fitness cost in terms of seed germination, and thus potential empirical support for the expectation of trait trade-offs as a consequence of adaptation to novel environments.

适合度代价（fitness cost）常被用以解释多种有害因子作用下，植物防御（plant defense）相关遗传变异（genetic variation）的维持机制。尽管学界普遍预期抗性代价广泛存在，但在自然环境中却难以对其进行检测。为探究抗性是否会带来适合度代价，我们针对对草甘膦除草剂（glyphosate）抗性水平存在分化的圆叶牵牛（Ipomoea purpurea）的遗传品系，开展了其存活情况与适合度的检测研究。我们设置了大型田间试验，在施加除草剂后评估各遗传品系的存活状况，并在无除草剂环境下测定分歧选择品系（divergent selection lines）的适合度。研究结果显示，在除草剂存在的条件下，经高抗性筛选的遗传品系死亡率显著低于对照组与感性品系，但未发现抗性品系在无除草剂环境下结籽量更少的相关证据。然而，感性品系所产生的种子萌发活力高于抗性品系与对照组，这为基于种子萌发维度的适合度代价提供了一定实证依据，也为“适应新生境会引发性状权衡（trait trade-offs）”这一理论预期提供了潜在的实验支持。