Japanese walnuts (Juglans mandshurica) are known to be seed‐dispersed by the hoarding of two species of rodents, Japanese squirrels (Sciurus lis) and large Japanese field mice (Apodemus speciosus). The previous study showed that the squirrel transported and stored larger walnut seeds farther, whereas the mice transported smaller seeds farther. Divergent selection by different seed dispersers may play an important role in differentiation between local walnut populations, in which understanding seed size heritability is crucial. This study aims to determine how the seed size selected by rodents affects the initial growth of walnuts and to what extent walnut seed size is genetically determined. Sixty walnut seeds were collected from a small seed‐producing tree, and 50 walnut seeds from a large seed‐producing tree were sown and grown for 18 years. The seed size produced from each tree showed that the heritability of seed size was high (h2 = 0.52). When 50 smaller and 50 larger walnut seeds were planted under the same conditions, the dry weight of shoots and roots of the larger seeds was significantly greater than that of the smaller seeds, and root length was also significantly longer in the larger seeds. Seed size is heritable, so if squirrels are inhabiting, larger seeds, which are advantageous for regeneration, will be selected, and walnut trees producing larger seeds will be passed on to the next generation. Because selective hoarding has implications for seed establishment success, inhabiting a suitable seed disperser, the squirrel, is more critical for walnut regeneration than previously assumed.

中文翻译：

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核桃种子大小的遗传力和大种子的好处

日本核桃（核桃）已知通过囤积两种啮齿动物日本松鼠（松鼠）和大型日本田鼠（黑线姬鼠）。先前的研究表明，松鼠将较大的核桃种子运输和储存得更远，而老鼠则将较小的种子运输和储存得更远。不同种子传播者的不同选择可能在当地核桃种群之间的分化中发挥重要作用，其中了解种子大小的遗传力至关重要。本研究旨在确定啮齿动物选择的种子大小如何影响核桃的初始生长以及核桃种子大小在多大程度上是由基因决定的。从一棵小结籽树上采集了 60 颗核桃种子，从一棵大结籽树上采集了 50 粒核桃种子，播种并生长了 18 年。从每棵树产生的种子大小来看，种子大小的遗传力较高（H2= 0.52）。在相同条件下种植50粒较小核桃种子和50粒较大核桃种子时，较大种子的芽和根干重显着大于较小种子，并且较大种子的根长度也显着更长。种子大小是可以遗传的，所以如果有松鼠栖息，就会选择有利于再生的较大种子，而产生较大种子的核桃树就会遗传给下一代。由于选择性囤积对种子建立的成功具有影响，因此居住在合适的种子传播者松鼠中对于核桃再生比以前假设的更为重要。