Male Sterilization of Brassica napus Induced by Sulfonylurea Herbicides

To search for a new, efficient chemical hybridizing agent (CHA), 5 sulfonylurea herbicides (i.e., nicosulfuron, bensulfuron, amidosulfuron, tribenuron and ethametsulfuron) were evaluated. The effects of the agents on inducing male sterility as well as agronomic properties and yield traits of Brassica napus were determined for the analysis. The results showed that, aside from ethametsulfuron, these agents indeed turned the fertile rapeseeds sterile. The induction by nicosulfuron or bensulfuron was less effective, with an average complete male sterility rate merely 30.8% for nicosulfuron and 21.0% for bensulfuron. But their incomplete male sterility and the phytotoxicity rates reached 56.4% and 63.4%, respectively, for nicosulfuron, and 18.4% and 20.0%, respectively, for bensulfuron, which exerted a significant negative effect on agronomic traits and seed yield on B. napus. On the other hand, amidosulfuron and tribenuron were most effective with their average male sterility rates that reached 96.55% and 97.9%, respectively, and the average complete male sterility rate 88.55% and 92.51%, respectively, according to the results obtained by the stem-smearing and spraying methods. In addition, the latter two agents did not carry any significant differences from CK1 on the agronomic traits or seed yield. Therefore, amidosulfuron and tribenuron were expected to be applied in the heterosis utilization of chemical hybridizing of B. napus after further optimization on the preparation, additives and application of the agents.