SummaryRapeseed (Brassica napus) is a globally significant oilseed crop with strong heterosis performance. Recessive genic male sterility (RGMS) is one of the key approaches for utilizing heterosis in B. napus. However, this method faces the inherent challenge of being time‐consuming and labour‐intensive for removing fertile plants during seed production. Here, we report a hypocotyl length‐regulated gene, BnHL, which is closely linked to a known fertility gene, BnMs2, serving as a seedling morphology marker. This marker could be used to identify fertile plants in the breeding of RGMS lines based on hypocotyl traits. By targeting the BnHL gene, both homozygous and heterozygous edited mutants exhibited significantly longer hypocotyls than the wild type (WT). Furthermore, germination experiments revealed that 7 days after seed germination, the difference in hypocotyl length between the mutant and the WT seedlings reached its maximum, effectively distinguishing fertile plants under both white (W) and red/far‐red (R/FR) light. Mutations in BnHL did not result in significant changes in main agronomic traits. Thus, this study provides a comprehensive strategy for screening and identifying a new morphological marker gene for early screening in RGMS hybrid breeding with completely non‐transgene during the whole production.

中文翻译：

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一种通过新型下胚轴长度调控基因 BnHL 杂交育种的 Brassica napus 杂交品种的可见苗期筛选系统


摘要油菜籽（Brassica napus）是一种具有全球重要性的油料作物，具有很强的优势表现。隐性基因雄性不育 （RGMS） 是利用甘蓝型油菜优势的关键方法之一。然而，这种方法面临着在种子生产过程中去除肥沃植物耗时且劳动密集型的固有挑战。在这里，我们报道了一个下胚轴长度调节基因 BnHL，它与已知的生育基因 BnMs2 密切相关，作为幼苗形态学标记。该标记可用于在基于下胚轴性状的 RGMS 品系育种中鉴定可育植物。通过靶向 BnHL 基因，纯合子和杂合子编辑的突变体都表现出比野生型 （WT） 明显更长的下胚轴。此外，发芽实验表明，种子发芽后 7 天，突变体和 WT 幼苗之间的下胚轴长度差异达到最大，在白光 （W） 和红光/远红光 （R/FR） 下有效区分了可育植物。BnHL 的突变不会导致主要农艺性状的显着变化。因此，本研究为在整个生产过程中完全非转基因的 RGMS 杂交育种中筛选和鉴定新的形态学标记基因提供了早期筛选的综合策略。