The Identification Of Potato Scab Pathogen And Evaluation Of Potato Variety Resistance Against Potato Scab

Potato common scab is a kind of skin disease caused by Streptomyces. The disease occurred in different levels of potato producing areas in China and increased year by year. The incidence rate of Yunnan Province is up to 30%, the incidence of some field is 100%.As the third province of 10 million tons of potato production in the country, in 2014,, the potato acreage of Yunnan Province reached 673,000 hm2, with a total output of 13 million 610 thousand tons. Therefore a clear composition of Yunnan Province scab pathogen and resistance evaluation of Potato Varieties(lines) resources is imminent.The research isolate the diseased samples from Yunnan province potato production areas, confirm constitute of Yunnan Province scab pathogen by the pot experiment, morphological identification, molecular identification. The resistance to potato scab of 23 potato varieties were evaluated by pot experiment and field experiment.Analyzed the different varieties and 10 resistance related factor,defined the relationship between the factors and the resistance of potato. The results are as follows:1) The research identified 7 potato scab pathogens including S.anulatus、S.scabies、S.acidiscabies、S.griseus、S.europaeiscabiei、S.caviscabies、S.enissocaesilis。2) The standard of resistance evaluation was established。The study screened 3 resistance varieties through the pot experiment, including C88,Awu potato and Jingshu1.The study screened 2 middle resistance varieties through the field experiment,including Ziyun1 and Jingshu1.3) Starch content, anthocyanin content, PPO activity, water content made a contribution to potato resistance. The greater the starch content, anthocyanin content, PPO activity, the stronger the resistance of potato. The lower the water content, the stronger the resistance of potato. The more uniform and denser the structure of the potato skin, the stronger the resistance of potato. Starch content, anthocyanins, PPO activity, water content and epidermal structure in a certain extent, reflect the potato resistance against scab.