青花菜根肿病苗期抗性鉴定技术的建立

The development of artificial inoculation system for assessment of resistance to clubroot in broccoli seedlings

为建立快速、有效的青花菜根肿病苗期抗性鉴定技术,将芸薹根肿菌Plamodiophora brassicae Woron.人工接种于高感根肿病青花菜自交系90196,研究了接种菌液浓度、接种寄主苗龄、接种基质p H和接种方法等对人工接种鉴定效果的影响。结果表明,在一定范围内,根肿病发病率及病情指数随着接种菌液浓度的升高而增大,接种菌液浓度为3×108CFU/m L时,发病率及病情指数分别为97.22%和86.11,可以反映寄主真实的抗性水平;接种寄主苗龄为2~6叶期均能使植株发病,但2~3叶期发病效果最佳;接种基质偏酸性(p H 5~6)有利于根肿病的发生;使用伤根灌菌法进行鉴定,青花菜根肿病发病率和病情指数均最高,分别为100.00%和88.10,优于蘸根法和浸芽法。用已知抗性水平的12个自交系和8个杂交种进行验证,鉴定结果表明该苗期抗性鉴定技术可客观反映供试材料的实际抗性水平。

In order to develop a rapid and effective technique for assessment of resistance to clubroot by using artificial inoculation of broccoli materials with Plamodiophora brassicae Woron.,parameters of the inoculation system including levels of inocula,growth stage of seedlings,matrix p H and inoculation methods were studied using broccoli inbred line 90196（ highly susceptible to clubroot） in the laboratory.The results showed that the disease incidence and disease index of clubroot increased in a certain range along with the increase of inocula,and the actual levels of plant resistance could be revealed with the inoculum of 3 × 108 CFU / m L,for which the disease incidence and disease index were 97. 22% and86. 11,respectively. The inoculation efficiency was highest on seedlings of 2- 3 leaf stage,although it was able to cause clubroot throughout 2- 6 leaf stages. The partially acidic（ p H 5- 6） condition was more favorable to the occurrence of clubroot. The efficiency of inoculation by injured root irrigation was better than other treatments,of which the disease incidence and disease index were 100. 00% and88. 10,respectively. The technique was verified by inoculation of 12 inbred lines and eight hybrids with known levels of resistance. The results proved that the established assessment system is able to identify levels of plant resistance to Plamodiophora brassicae in broccoli seedlings.