Abstract:Fruits contain abundant nutrients，but they are prone to infectious diseases during postharvest storage or transportation，resulting in pulp decay and quality decline，causing serious economic losses. In this study，in order to screen the optimal concentration of CaCl2 for inhibitory effect and explore the resistance induction mechanism on apple fruit under its optimal binding concentration with double yeast，the optimal culture time after adding CaCl2 was determined to be 24 h by the inoculation experiment in vitro. In vivo experiment，it was determined that different concentrations of CaCl2 induced double yeast had inhibitory effect on apple penicilliosis，of which 2.0% CaCl2 had the best inhibitory effect. Through the growth dynamics of apple wound and surface，it was found that 2.0% CaCl2 could promote the rapid colonization of double yeast. 2.0% CaCl2 induction could significantly increase the activities and substance contents of enzymes related to phenylpropane metabolism and active oxygen metabolism in apples. Compared with the control and the use of double yeast compound，CaCl2 treatment could enhance the biocontrol effect of antagonistic yeast. On the one hand，it can promote the growth and colonization of antagonistic yeast；on the other hand，it can reduce the incidence of fruit and enhance the disease resistance of fruit.