Abstract: This study focused on the effects of treatments with different concentrations of potassium sorbate (1, 3, 5 and 7 g/L), and/or calcium chloride (5, 10, 15 and 20 g/L) on the resistance to Botrytis cinerea in sweet cherry from the cultivar ‘Qinying 1’. The optimal treatment concentration was screened by measuring the percentage inhibition of mycelial growth, germ tube growth and spore germination of Botrytis cinerea. The results indicated that all treatments could concentration dependently inhibit mycelial growth and germ tube elongation of Botrytis cinerea to different degrees compared with control group and significantly decrease the spore germination rate, and that the best effect was attained by treatments with 20 g/L calcium chloride and 5 g/L potassium sorbate. The inhibitory effect of preharvest spraying with 20 g/L CaCl2 and/or postharvest spraying with 5 g/L potassium sorbate on gray mold incidence, lesion diameter and related enzyme activities in sweet cherry inoculated with Botrytis cinerea during storage for 5 days at (23 ± 1) ℃ was evaluated using sterile water as a control. It turned out that all three treatments effectively inhibited the growth of inoculated Botrytis cinerea and delayed lesion expansion. In addition, both potassium sorbate and CaCl2 could significantly inhibit the content of malondialdehyde (malondialdehyde) and induce the synthesis and accumulation of resistance-associated enzymes (polyphenol oxidase, peroxldase, chitinase, β-1,3-glucanase), increasing the enzyme activities at 1 day or 3 days after inoculation. The combined treatment with 5 g/L potassium sorbate and 20 g/L calcium showed the best inhibitory effect on Botrytis cinerea. The results of this study can provide useful information for reducing the disease caused by invasion of Botrytis cinerea and preserving postharvest sweet cherry.

Key words: sweet cherry, gray mold, potassium sorbate, calcium, resistance-related enzyme