Cabbage is a globally cultivated vegetable with obvious heterosis. The main method used for cabbage breeding is the creation of hybrid combinations with inbred lines, and how to combine the parents plays a crucial role in cabbage breeding. Therefore, it is urgent to classify heterotic groups by molecular markers. In this study, single nucleotide polymorphism (SNP) markers were developed on the basis of whole-genome resequencing data of 50 inbred lines. A total of 2.54 × 106 SNP loci were obtained by aligning resequencing data to the reference genome of cabbage. Finally, five hundred SNP markers among 50 re-sequenced genotypes were further selected on the basis of a high polymorphism information content, a high minor allele frequency, a wide average distribution and low heterozygosity. Then, 442 SNP markers were successfully converted into kompetitive allele-specific PCR (KASP) markers, accounting for 88.4% of all 500 SNP markers. The cabbage inbred lines included three ecotypes: spring cabbage, autumn cabbage and winter cabbage. Based on the KASP genotyping data, the genetic similarity among inbred lines was analyzed, and the heterotic groups within each ecotype were classified. Seven heterotic groups were identified for spring cabbage (77); six, for autumn cabbage (70); and five, for winter cabbage (97). In addition, we found parents of 48 developed elite combinations were all from different heterotic groups or subgroups, which verified that the group classification was accurate and useful. Therefore, we suggest that the parents of combinations should be selected from different heterotic groups or subgroups, which will guide parental selection in cabbage breeding and improve breeding efficiency.

中文翻译：

---

244 个甘蓝自交系的竞争性等位基因特异性 PCR (KASP) 基因分型和杂种优势群分类 (Brassica oleracea L. var. capitalata)

卷心菜是全球栽培的蔬菜，具有明显的杂种优势。白菜育种的主要方法是建立与自交系的杂交组合，而如何将亲本组合在白菜育种中起着至关重要的作用。因此，迫切需要通过分子标记对杂种优势群进行分类。在这项研究中，基于 50 个自交系的全基因组重测序数据开发了单核苷酸多态性 (SNP) 标记。通过将重测序数据与卷心菜参考基因组比对，共获得 2.54 × 106 个 SNP 位点。最后，基于多态性信息含量高、次要等位基因频率高、平均分布广、杂合度低的特点，在50个重测序基因型中进一步筛选出500个SNP标记。然后，442个SNP标记成功转化为竞争性等位基因特异性PCR（KASP）标记，占全部500个SNP标记的88.4%。甘蓝自交系包括三种生态型：春甘蓝、秋甘蓝和冬甘蓝。基于KASP基因分型数据，分析了自交系之间的遗传相似性，并对每个生态型内的杂种优势群进行了分类。春白菜鉴定了 7 个杂种优势组 (77)；六、秋白菜（70）；五、冬白菜（97）。此外，我们发现48个发育精英组合的亲本均来自不同的杂种优势群体或亚群，验证了群体分类的准确性和实用性。因此，我们建议组合的亲本应从不同的杂种优势群或亚群中选择，