The Current Status and Prospects of Molecular Marker Applications in Head Cabbage (Brassica oleracea var. capitata L.): A Review

Modern head cabbage (Brassica oleracea var. capitata L.) breeding is based on the application of molecular markers through marker-assisted selection (MAS). In hybrid breeding, critical markers are deployed to assess cytoplasmic male sterility (CAPS and SSR for orf138), genic male sterility (KASP markers for Ms-cd1, InDel for ms3, and BoCYP704B1), fertility restoration (InDel marker for Rfo), combining ability and genetic diversity (using SSR and KASP marker sets), and to ensure F₁ hybrid seed genetic purity (RAPD and SSR markers sets). Disease resistance, a well-developed category due to frequent monogenic control, includes markers for major pathogens, including those for Fusarium wilt (for Foc-Bo1 gene), black rot (race 1–7 specific SSR and InDel markers), clubroot (Kamogawa, Anno, and Yuki isolates), and downy mildew (BoDMR2 InDel marker). Markers have also been identified for key agronomic and morphological traits, such as those governing petal color (InDel markers for BoCCD4), leaf waxiness (BoGL1, BoGL-3, Cgl1, Cgl2, BoWax1, and BoCER2), and leaf color (ygl-1, BoMYB2, BoMYBL2-1). The review also included markers for resistance to abbioticaly induced negative physiological processes, such as head splitting (QTL SPL-2-1, Bol016058), bolting (resistance loci-associated SSR marker), prolonged flowering time (BoFLC1,2 genes), and high- and low-temperature tolerance (BoTPPI-2, BoCSDP5, BoCCA1). Despite these advancements, the review highlights that the marker repertoire for cabbage remains limited compared with other Brassicaceae species, particularly for complex polygenic traits. This synthesis is a valuable resource for breeders and researchers, facilitating the development of superior head cabbage cultivars and hybrids.