Trees with weeping traits have been prized for centuries because of their unique shape. Weeping trees of various species have been selected and propagated for their ornamental appeal as landscape plants, but there is limited information on the genes that control weeping. The genetic control of weeping in Japanese chestnut (Castanea crenata Sieb. et Zucc.) is reported to involve a dominant or recessive gene depending on the genetic background. In every case examined to date, weeping is controlled by a single gene of unknown location. Here, we identified the exact position of the dominant gene controlling the weeping trait in the Japanese chestnut. Using the genome scanning approach, which can cost-effectively screen for markers linked to traits, we first mapped this gene, referred to here as Weep, to the middle of linkage group L. Then, we developed new simple sequence repeat (SSR) markers using the genomic resources to enrich the target region. Using these markers and previously reported markers, we constructed the linkage group covering most of the chromosome (60.9 cM) with an average marker density of 4.7 cM per marker. Weep was located within a 3.0-cM genome region. SSR marker CmSca01437 co-segregated with Weep in all 138 F₁ plantlets of a Tsukuba-38 × 668-6 cross. Our identification of the exact locus of the dominant weeping gene in Japanese chestnut, in conjunction with previous studies of recessive weeping genes in this and other tree species, furthers our understanding of the genetic mechanism of the weeping trait.

具有哭泣特征的树木由于其独特的形状而被人们珍视了几个世纪。人们已经选择并繁殖了各种种类的哭泣树，以作为观赏植物作为园林植物，以使其具有观赏性，但有关控制哭泣的基因的信息有限。据报道，日本板栗（Castanea crenata Sieb。et Zucc。）的哭泣遗传控制涉及显性或隐性基因，具体取决于遗传背景。迄今为止，在每种情况下，哭泣都是由未知位置的单个基因控制的。在这里，我们确定了控制栗树哭泣性状的显性基因的确切位置。使用基因组扫描方法，该方法可以经济高效地筛选与性状相关的标记，我们首先对该基因进行了定位，在这里称为Weep到连锁群L的中间。然后，我们利用基因组资源开发了新的简单序列重复（SSR）标记，以丰富目标区域。使用这些标记和先前报道的标记，我们构建了覆盖大部分染色体（60.9 cM）的连锁组，每个标记的平均标记密度为4.7 cM。哭泣位于3.0-cM基因组区域内。在Tsukuba-38×668-6杂交的所有138 F ₁幼苗中，SSR标记CmSca01437与Weep共同分离。我们对日本板栗中主要的哭泣基因的确切基因座的鉴定，再加上先前对该树和其他树种的隐性哭泣基因的研究，进一步加深了我们对哭泣性状遗传机制的理解。