Objective To obtain cultivar (lines) of rapeseed resistant to blackleg caused by Leptosphaeria biglobosa 'canadensis' (Lbc), we screened highly virulent Lbc strains collected from spring rapeseed in Xinjiang of China, and used for identification of resistance of rapeseed varieties to blackleg.
Methods Using the needle-wounded cotyledons inoculation method, 30 Lbc strains from Xinjiang were compared for virulence on Brassica napus cultivar Zhongshuang No. 9. Then,the highly virulent strain Lbc6-14 was inoculated on 110 spring rapeseed cultivars (Brassica spp.) for comparison of their resistance at the cotyledons stage.
Results The 30 investigated Lbc strains showed a significant difference in virulence against the cultivar Zhongshuang No. 9. Strain Lbc6-14 was selected due to its high virulence and prolific spore production, therefore, it was used for resistance identification. Results of the resistance identification showed that the 110 cultivars (lines) showed a significant difference in resistance to infection by Lbc6-14. Six cultivars (lines) showed high resistance, 12 cultivars (lines) showed moderate resistance, 14 cultivars (lines) showed weak resistance, 25 cultivars (lines) showed weak susceptibility 34 cultivars (lines) showed moderate susceptibility, and 19 cultivars (lines) showed high susceptibility.
Conclusion The population of 30 Lbc strains from Xinjiang showed a significant differentiation in virulence on rapeseed. Six highly resistant cultivars (lines) and 19 highly susceptible cultivars (lines) were identified from 110 spring rapeseed cultivars (lines). This result laid a foundation for further breeding rapeseed cultivars resistant to blackleg disease.
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