Most tea plants (Camellia sinensis) are considered self-incompatible (SI). It is difficult to identify self-compatible (SC) tea mutants through controlled hand-pollination. ‘Ziyan’ (ZY), a purple tea cultivar, was previously found to be SC by pedigree relationship reconstruction of its offspring using DNA markers. To assess the inbreeding depression in C. sinensis, in this study we identified 29 selfing progeny plants (SP) of ZY and compared their fitness traits and contents of secondary metabolites with the out-crossing progeny (OP, n = 38 plants) and the clonal mother ZY (n = 3 plants). The results showed that fitness traits, including root-collar diameter, matured leaf area, and fruit number of SP, were significantly lower than those of OP and ZY. Notably, the average fruit number of SP was only 9.0 % of ZY and 7.3 % of OP. The spring bud flush time of SP was also significantly later than the OP as indicated by the sprouting index on March 30th, 2020. However, the average content of anthocyanin of SP was 3.67 times that of OP. The total catechin and caffeine contents in SP were lower than those in OP and ZY, but less significantly. Together, the results indicated a strong inbreeding depression of fitness traits in the first selfing generation of ZY, while the impacts on secondary metabolites were not consistent. In addition, a possible homozygous lethal allele was found on LG03. The findings of this study have useful implications for inbred line-based breeding and researches in C. sinensis.

大多数茶树（山茶）被认为是不相容的（SI）。通过受控的手传授粉很难鉴定出自相适应的（SC）茶突变体。通过使用DNA标记对其后代进行系谱关系重建，以前发现紫色茶品种'Ziyan'（ZY）是SC。评估中华绒螯蟹的近交抑郁，在这项研究中，我们鉴定了ZY的29个自交子代植物（SP），并将其适合性状和次生代谢产物的含量与异交后代（OP，n = 38株）和克隆母体ZY（n = 3株）进行了比较。 。结果表明，适性性状，包括根领直径，成熟叶面积和SP的果实数，均显着低于OP和ZY。值得注意的是，SP的平均果实数仅为ZY的9.0％和OP的7.3％。根据2020年3月30日的发芽指数，SP的春芽冲洗时间也显着晚于OP。但是，SP的花色苷平均含量是OP的3.67倍。SP中的儿茶素和咖啡因总含量低于OP和ZY中的儿茶素和咖啡因含量，但显着降低。一起，结果表明，在ZY的第一自交世代中，适应性状的近交抑制力很强，而对次生代谢产物的影响却不一致。另外，在LG03上发现了可能的纯合致死等位基因。这项研究的发现对基于近交系的育种和对马铃薯的研究具有有益的启示。山茶。