Adaptation through natural selection may be the only means by which small and fragmented plant populations will persist through present day environmental change. A population's additive genetic variance for fitness (VA(W)) represents its immediate capacity to adapt to the environment in which it exists. We evaluated this property for a population of the annual legume Chamaecrista fasciculata through a quantitative genetic experiment in the tallgrass prairie region of the Midwestern United States, where changing climate is predicted to include more variability in rainfall. To reduce incident rainfall, relative to controls receiving ambient rain, we deployed rain exclusion shelters. We found significant VA(W) in both treatments. We also detected a significant genotype‐by‐treatment interaction for fitness, which suggests that the genetic basis of the response to natural selection will differ depending on precipitation. For the trait‐specific leaf area, we detected maladaptive phenotypic plasticity and an interaction between genotype and environment. Selection for thicker leaves was detected with increased precipitation. These results indicate capacity of this population of C. fasciculata to adapt in situ to environmental change.

中文翻译：

---

估计 Chamaecrista fasciculata 适应降水变化的能力

通过自然选择进行适应可能是小而分散的植物种群在当今环境变化中持续存在的唯一手段。种群的适应度加性遗传方差 (VA(W)) 代表其适应所处环境的直接能力。我们通过在美国中西部高草草原地区进行的定量遗传实验评估了一年生豆科植物 Chamaecrista fasciculata 的这一特性，预计该地区的气候变化将包括更多的降雨变异性。为了减少事故降雨，相对于接收环境降雨的控制，我们部署了防雨庇护所。我们在两种处理中都发现了显着的 VA(W)。我们还检测到了显着的基因型-治疗相互作用对健康，这表明对自然选择的反应的遗传基础将因降水而异。对于性状特定的叶面积，我们检测了适应不良的表型可塑性以及基因型与环境之间的相互作用。随着降水量的增加，检测到选择较厚的叶子。这些结果表明 C. fasciculata 种群就地适应环境变化的能力。