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.

适合度代价常被用于解释多种有害因子作用下，植物防御相关遗传变异的维持机制。尽管学界普遍预期抗性代价广泛存在，但在自然环境中却极难被检测到。为探究抗性是否会带来适合度代价，我们针对对草甘膦（glyphosate）除草剂抗性水平存在分化的普通圆叶牵牛（Ipomoea purpurea）的遗传品系，开展了存活与适合度相关研究。我们设置了大规模田间试验，分别在喷施除草剂后评估各品系的存活率，并在未喷施除草剂的条件下测定分歧选择品系的适合度表现。研究结果显示：在除草剂存在的环境中，经选育获得高抗性的遗传品系，其存活率显著高于对照品系与易感品系；但未发现抗性品系在无除草剂环境下结籽量更少的证据。然而，易感品系所结种子的活力显著高于抗性品系与对照品系，这为从种子萌发维度衡量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”这一理论预期提供了潜在的实验支持。