Resistance Identification And Related Physiological Analysis Of 11 Chinese Cabbage Cultivars To Clubroot Disease From Tonghai County

Clubroot disease is a globally widespread disease caused by Plasmodiophora brassicae,commonly known as "major root disease." Most cruciferous plants are easily infested by this disease.The occurrence of diseases will lead to a decline in crop yield and quality.It has become one of the major obstacles to the development of Yunnan's highland vegetables.Tonghai is a development demonstration county of “Yun vegetables”.Its dominant cultivars of summer and autumn vegetables are cruciferous cabbages and cabbages.Therefore,the selection of root-swelled resistant cultivars suitable for cultivation in Tonghai is conducive to the development of the vegetable industry.In this study,the current 11 major cruciferous Chinese cabbage cultivars in Yunnan were used as materials to evaluate their resistance to clubroot disease.Combined with the results of resistance identification,the relationship between the changes in the activities of defense enzymes(POD,SOD,CAT,MDA),soluble protein and soluble sugar content at the seedling stage and the disease resistance of clubroot was analyzed to find the resistance cultivars and possible physiological resistance identification indicators.The main findings are as follows:1.The results of resistance identification showed that 11 tested materials for the clubroot strains in Tonghai area were 3 high-resistant cultivars,2 resistant cultivars and 6 sensitive cultivars in terms of resistance classification.The six susceptible species are not suitable for planting in wards.Among them,three high-resistance cultivars of Bengsheng CR-12,Bosesheng CR-9 and Xinkanggen CR can be used as new sources of resistance genes for breeding in furture.2.The relative soluble sugar content and the disease index of leaves were significantly correlated at 25 and 35 days after inoculation;relative SOD activity of leaves at 35 and 45 days after inoculation,relative soluble sugar content of leaves at 45 days after inoculation,and leaves of 25 days.There is a correlation between the relative soluble protein content and the disease index.3.There was also a correlation between the relative values of the physiological indices of roots and the disease index in the three periods after inoculation.The correlation between relative POD activity and disease index at 35 days after inoculation was extremely significant;relative POD activity at 25 days and 45 days after inoculation,relative soluble sugar content at root at 25 days after inoculation,and disease index was significantly correlated..4.The principal component analysis showed that soluble sugar content,POD activity in roots,SOD activity in leaves and soluble protein content in roots of Chinese cabbage after inoculation with P.brassicae could be used as auxiliary indicators for early selection resistance of Chinese cabbage.Leaf POD activity,leaf soluble protein content,SOD activity in roots,root soluble sugar content and clubroot disease resistance were correlated.