Documenting if plants exhibit kin competition avoidance in intraspecific plant interactions is relevant both to improve crop growth, and to understand diversity and composition in natural plant communities. However, a number of confounding mechanisms complicates detecting kin competition avoidance from experiments comparing plants growing with kin and non-kin neighbors. We conducted complementary greenhouse experiments using genotypes from four populations of the annual Medicago minima, which in a previous study showed higher survival when interacting with kin relative to non-kin. We show that genotypes vary in kin competition avoidance, and in competitive ability, but find no indication of complementary resource use. Importantly, from our first experiment of root growth behavior, we know that some genotypes exhibit kin competition avoidance. Yet, the variation in competitive ability we find in our second experiment, where plants grow in mini communities together with either kin or unrelated genotypes, can alone explain the variation we observe in growth and biomass among communities. In our case, the genotypes with highest competitive ability were also those that showed kin competition avoidance. This confounding effect obscured the disentangling of mechanisms underlying difference in growth between kin and non-kin interactions. When silencing root exudates by adding activated carbon to a subset of our genotype combinations, we found increased size asymmetry of plants grown together, and mostly in kin communities. This suggests that plants recognize the identity of neighbors via root exudates, and compete less with neighbors recognized as kin. To detect kin competition avoidance we suggest designing experiments that pair unrelated genotypes with similar competitive abilities. Such design, combined with silencing root exudates would be powerful to detect whether plants show kin competition avoidance or not.

记录植物在种内植物相互作用中是否表现出避免亲缘关系竞争，与改善作物生长以及了解天然植物群落的多样性和组成有关。但是，许多混淆机制使通过比较有近亲和非近亲邻居生长的植物而进行的避免亲缘竞争的检测变得复杂。我们使用来自一年生苜蓿最小值的四个种群的基因型进行了补充温室实验，在先前的研究中，与亲戚互动时，与非亲戚互动时，存活率更高。我们显示基因型在避免亲属竞争和竞争能力方面各不相同，但没有发现互补资源利用的迹象。重要的是，从我们的根系生长行为的第一个实验中，我们知道一些基因型表现出避免亲缘竞争。然而，我们在第二个实验中发现的竞争能力变化，即植物在小型社区中与亲缘或无关基因型一起生长，可以单独解释我们在社区中生长和生物量的变化。在我们的案例中，具有最高竞争能力的基因型也表现出避免亲属竞争的基因型。这种混淆效应掩盖了亲缘和非亲缘相互作用之间生长差异的潜在机制的混乱。通过将活性炭添加到我们的基因型组合的一个子集中来使根系分泌物沉默，我们发现在一起生长的植物（主要是近亲属）的尺寸不对称性增加。这表明植物通过根系分泌物识别邻居的身份，并且与被认为是近亲的邻居竞争较少。为了检测避免亲属竞争，我们建议设计实验，将不相关的基因型与相似的竞争能力配对。这种设计加上沉默的根系分泌物，将对检测植物是否显示出避免亲缘竞争具有强大的作用。我们发现在一起生长的植物，尤其是在亲属社区中，植物的尺寸不对称性增加。这表明植物通过根系分泌物识别邻居的身份，并且与被认为是近亲的邻居竞争较少。为了检测避免亲属竞争，我们建议设计实验，将不相关的基因型与相似的竞争能力配对。这种设计与沉默根系分泌物的结合将对检测植物是否显示出避免亲缘竞争具有强大的作用。我们发现在一起生长的植物，尤其是在亲属社区中，植物的尺寸不对称性增加。这表明植物通过根系分泌物识别邻居的身份，并且与被认为是近亲的邻居竞争较少。为了检测避免亲属竞争，我们建议设计实验，将不相关的基因型与相似的竞争能力配对。这种设计加上沉默的根系分泌物，将对检测植物是否显示出避免亲缘竞争具有强大的作用。