油菜感抗品种混播对根肿病防控效果的影响

近年来,油菜根肿病危害在我国呈蔓延趋势,主要原因是化学防治成本高且效果差。实际生产中,种植抗性品种是最经济、最有效的措施。不同抗感品种混播,在保证产量稳定的前提下可减轻对病原菌小种的选择压,从而稳定病原菌种群结构,延长抗性品种使用寿命。本试验在安徽绩溪、云南临翔2个油菜根肿病严重发生区域,选择2组互为近等基因系的感病、抗病的油菜品种,按不同比例混播(感病、抗病比例分别为10:0、1:9、2:8、3:7和0:10),在根肿病明显发生后调查发病率等指标。结果表明:不同比例感病、抗病油菜品种混播均降低了根肿病发病率和病情指数,并稳定油菜产量和品质;且油菜发病株率随抗病品种的比例下降而升高,但均低于理论发病率;不同抗性组合间混播的相对防效(REM)均低于1,且随着作物生育期的推迟呈现下降趋势。以上结果表明,油菜感抗品种混播对根肿病有较好的防控效果。本研究主要在大田条件下明确了2组不同抗感近等基因组合混播对油菜根肿病的防治效果,可为油菜根肿病防治提供思路和对策。

Controlling efficiency against clubroot disease of rapeseed by mixed-cropping of susceptible and resistant cultivars

In recent years, rapeseed clubroot disease has spread widely in China, and the cost of the chemical control is high while the efficiency is low. Using resistant varieties is the most economical and efficient way to control this disease. Mixed-cropping different resistant varieties can improve the control efficiency of crop diseases, but the research on it has not been reported. In two naturally-infested locations of clubroot diseases in Jixi of Anhui province and Linxiang of Yunnan province, two pairs of susceptible and resistant cultivars were used (highly resistant variety Huashuang 5R mixed with highly susceptible variety Huashuang 5 and highly resistant variety Huayouza 62R mixed with highly susceptible variety Huayouza 62). Seeds of each pair were mixed at different ratios (10:0, 1:9, 2:8, 3:7, and 0:10) and sown in the two locations respectively. The incidence rate was surveyed after occurrence of clubroot disease. The mixed-cropping at different ratios of susceptible and resistant cultivars decreased the incidence and disease index of clubroot disease, and stabilized the yield and quality of rapeseed. The actual incidence rate in the mixed cropping treatment increased with the decrease of resistant cultivar proportion, which was from 5.7% to 17.1% at Jixi and from 4.4% to 32.1% at Linxiang for Huashuang 5R/Huashang 5, while from 5.7% to 18.6% at Jixi and from 2.1% to 12.0% at Linxiang for Huayouza 62R/Huayouza 62 respectively, and significantly lower than the theoretical disease incidence rate. The relative effectiveness of mixture of the two pairs of cultivars were lower than 1, which indicates that the mixed-cropping of susceptible and resistant cultivars has positive effect. This study mainly clarified the control effect of mixed-cropping two different Near-isogenic lines with different resistance levels on clubroot disease, which can provide new ideas and countermeasures for the prevention of clubroot disease.