菜心Brassica oxyrrhina胞质不育系的转育研究OA

Using a cytoplasmic male sterile(CMS)line of Brassica napus carrying cytoplasm from Brassica oxyrrhina as the maternal parent,we developed a stable CMS line in flowering Chinese cabbage(Brassica rapa subsp.parachinensis)through interspecific hybridization followed by six backcrosses,assisted by embryo rescue and a speed breeding system.The line was comprehensively characterized for morphological traits,pollen fertility,seed-setting performance,and cytoplasm-specific molecular markers.The CMS line exhibited typical floral morphology of flowering Chinese cabbage,featuring degenerated stamens with shortened filaments and shriveled anthers while nectaries developed normally.Acetic acid-carmine staining revealed aborted pollen grains,characterized by small,round,anucleate,and stained pale brown.Scanning electron microscopy further showed a lack of sporopollenin deposition and the collapse of germination apertures in the sterile pollen,consistent with classical CMS phenotypes.Field evaluations confirmed complete self-sterility;however,under open pollination,plants produced an average of 12 seeds per silique,indicating strong outcrossing compatibility.Comparative mitochondrial genome analysis enabled the development of a cytoplasm-specific KASP marker,KOX3,which reliably discriminates cytoplasm from Brassica oxyrrhina(C/C genotype)from other cytoplasmic types(T/T genotype).This novel CMS line provides a valuable germplasm resource for heterosis breeding in flowering Chinese cabbage,and the KOX3 marker offers a robust molecular tool for rapid cytoplasm identification and purity assessment of CMS lines.