Inducing male sterility in Brassica napus L. by a sulphonylurea herbicide, tribenuron-methyl

A sulphonylurea herbicide, tribenuron-methyl, methyl 2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl) methylamino] carbonyl] amino] sulphonyl] benzoate, was used to induce male sterility in rapeseed. Application of 0.2 mu g tribenuron-methyl per plant at the bolting stage with the longest floral bud < 2 mm and repeated 15 days afterwards, resulted in 94.5-100% plants being male sterile in six different breeding lines, but combined with low phytotoxicity. However, excessive double application of the chemical (> 0.2 mu g per plant) did have some significant impact on rapeseed, including stunting, fading leaves and petals, reduction in the size of floral parts and a shortened duration of flowering. The percentage of hybrid seeds from '84004' treated with 0.2 mu g x 2 tribenuron-methyl per plant and pollinated by a male parent 'Huaye' was 92.7%, which met the hybridity requirement in China. The results suggest that tribenuron-methyl could be used as an efficient chemical hybridizing agent.