Allo‐genome‐induced chromosomal abnormalities of progeny reduces transgene flow risk from glufosinate‐resistant Brassica napus to wild Brassica juncea

BACKGROUND: Herbicide-resistant (HR) oilseed rape (Brassica napus, AACC, 2n = 38) is the potential for transgenes to spread to its wild relative, Brassica juncea (AABB, 2n = 36). Previous research identified gene silencing in these progenies, observing plants that carried the HR gene PAT but did not express it normally (silenced, or r-s plants). RESULT: We found that r-s plants exhibited more stable inheritance compared to plants normally expressing PAT (expressed, or r-e, plants). Chromosome numbers in backcross progenies of r-s plants were consistently around 2n = 36. Specifically, r-s plants self-pollinated by r-e plants also showed chromosome numbers concentrated around 2n = 36, whereas in the r-e plants self-pollinated by r-e plants displayed numbers concentrated around 2n = 37. The meiotic indices of r-s plants exceeded 90%, further indicating their superior genetic stability compared with r-e plants. Despite these differences in genetic stability, r-s plants and r-e plants showed similar fitness. As the number of self-pollinated generations increased, the fitness of succeeding progeny gradually approached that of wild B. juncea. CONCLUSION: Integrating the transgene onto the C-chromosome, which exhibits low genetic stability, holds significant promise for reducing the gene flow risk associated with HR crops. © 2026 Society of Chemical Industry.