Studies On The Mechanism Of Disease Resistance Of Postharvest Apple To Gray Mold

To investigate resistance difference to gray mold,eight mid-late maturity varieties(‘Starkrimson',‘Golden Delicious',‘Jonagold',‘Comb',‘Qinguan',‘Fuji',‘Granny Smith'and‘Ralls')were inoculated Botrytis cinerea Pers during theroom temperature.At the first we screen varieties differently resisting to gray mold and then Further study Phenolic Metabolism,mass of relative resistance and activity of the enzymes responsible for resistance mechanism of apple fruits,which to reveal the mechanism of disease resistance of postharvest apple to Gray Mold.1.There is a resistance difference to gray mold among eight mid-late maturity varieties.‘Qinguan' performed the lowest morbidity degree.Although‘Granny Smith'had high incidence rate,the diameter of spot slowly extened.‘Ralls' and‘Comb' performed long latency and middle propagation of the diameter of spot.The incidence of disease spot of‘Golden Delicious' was the highest,followed by‘Starkrimson'and ‘Jonagold',while‘Fiji' was middle.In conclusion,for B cinerea ‘Qinguan'was high resistant varieties,‘Granny Smith'was middle-resistant varieties,‘Ralls' ?‘Comb'and‘Fiji' was susceptible cultivars,‘Starkrimson'?‘Jonagold' and‘Golden Delicious' was highly susceptible cultivars.2.To investigate apple disease resistance of grey mould,there apple cultivars(‘Qin Guan'?‘Fuji'and‘Golden Delicious')were inoculated Botrytis cinerea Pers during theroom temperature.The phenylalanine solution ammonia lyase(PAL),peroxidase(POD),polyphenol oxidase(PPO),chitinase(CHI)and?-1,3-glucanase(GLU)in the pulp of resistant varieties were higher than susceptible varieties',which increasing the content of flavonoids and lignin in the pulp of resistant varieties and reducing the degree of membrane lipid peroxidation,then decreasing the production of malondialdehyde(MDA),to improve its resistance to disease,.however the total Phenolic content in the pulp of ‘Qin Guan' is the lowest,in ‘Fuji' is the highest,in ‘Golden Delicious' is minimum.