Genetic characterization and fine mapping of a recessive genic male-sterile gene in flowering Chinese cabbage (Brassica rapa var. parachinensis).

Brassica vegetables exhibit pronounced heterosis; nevertheless, investigations on fertility-related genes are scarce. The present study scrutinized a recessive genic male-sterile line, 7-3A, capable of generating a completely sterile population, holding significant promise for flowering Chinese cabbage breeding. By whole-genome resequencing of sterile and fertile plants, the male-sterile gene was confined to approximately 185 kb on chromosome A07, situated between markers C719 and NP10 in Brassica rapa var. Chiifu-401. Notably, substantial structural variation was identified within this region across diverse Brassica rapa reference genomes. Despite discernible expression level disparities of a homologous gene, Bnams4b, between male sterile and fertile plants, no sequence divergence was detected. Further elucidation is required to pinpoint a novel sterile gene within the candidate interval. This investigation contributes to the advancement of both the molecular-assisted breeding scheme for flowering Chinese cabbage and the comprehension of male sterility mechanisms. [ABSTRACT FROM AUTHOR]