Laboratorio de Ecología Terrestre, Departamento de Ecología Humana, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav), 97310, Mérida, México.
Sci Rep. 2021 Oct 25;11(1):21017. doi: 10.1038/s41598-021-00592-0.
The clonal propagation of crops offers several advantages to growers, such as skipping the juvenile phase, faster growth, and reduced mortality. However, it is not known if the wild ancestors of most clonal crops have a similar ability to reproduce clonally. Therefore, it is unclear whether clonality was an ancestral condition, or if it evolved during domestication in the majority of these crops. Here, I assessed some traits that are relevant to clonal propagation using stem cuttings from chaya (Cnidoscolus aconitifolius) and compared these traits to those of its wild ancestor. Chaya is highly relevant crop to food security in its domestication center (Yucatan Peninsula) and is now cultivated in several countries. Chaya is also an excellent model for assessing the effect of domestication on clonality because wild relatives and selection targets are known. Specifically, I compared resistance to desiccation, water and resource storage, as well as the production of new organs (shoots and leaves) by the stems of wild and domesticated plants. I also compared their performance in root development and clone survival. I found that, relative to their wild ancestors, the stem cuttings of domesticated chaya had 1.1 times greater storage capacity for water and starch. Additionally, the stems of domesticated plants produced 1.25 times more roots, 2.69 times more shoots and 1.94 more leaves, and their clones lived 1.87 times longer than their wild relatives. In conclusion, the results suggest that artificial selection has optimized water and starch storage by stems in chaya. Because these traits also confer greater fitness (i.e. increased fecundity and survival of clones), they can be considered adaptations to clonal propagation in the agroecosystems where this crop is cultivated.
作物的无性繁殖为种植者带来了几个优势，例如跳过幼年期、生长更快和死亡率降低。然而，目前还不清楚大多数无性繁殖作物的野生祖先是否具有类似的无性繁殖能力。因此，尚不清楚无性繁殖是祖先的条件，还是在这些作物的大多数驯化过程中进化而来的。在这里，我使用马齿苋（Cnidoscolus aconitifolius）的茎段评估了与无性繁殖相关的一些性状，并将这些性状与野生祖先进行了比较。马齿苋是其驯化中心（尤卡坦半岛）粮食安全的重要作物，现在在几个国家种植。马齿苋也是评估驯化对无性繁殖影响的极好模型，因为已知其野生亲缘和选择目标。具体来说，我比较了抗旱性、水分和资源储存能力，以及茎产生新器官（枝条和叶子）的能力，比较了野生和驯化植物的这些特性。我还比较了它们在根系发育和无性系生存方面的表现。我发现，与野生祖先相比，驯化马齿苋的茎段具有 1.1 倍的水分和淀粉储存能力。此外，驯化植物的茎段产生的根多 1.25 倍，枝条多 2.69 倍，叶子多 1.94 倍，无性系的寿命比野生亲缘长 1.87 倍。总之，结果表明，人工选择优化了马齿苋茎段的水分和淀粉储存。由于这些性状也赋予了无性系更高的适应性（即增加了繁殖力和无性系的存活率），因此可以认为它们是在种植这种作物的农业生态系统中适应无性繁殖的特征。
