The effect of preharvest 28.6% chitosan composite film sprays for controlling the soft rot on kiwifruit and its defence responses

Abstract

This study evaluated the effects of preharvest plant 28.6% chitosan composite film (CTS-Fh) sprays on the postharvest quality and diseases in kiwifruit (Actinidia deliciosa cv. ‘Guichang’), it was screened and prepared by mixing chitosan, calcium, dextrin, ferulic acid and auxiliaries. 28.6% CTS-Fh solutions at different concentrations were sprayed three times during the fruit growing season. The obtained results show that 28.6% CTS-Fh sprays remarkably promoted the improvement of the yield and quality of the kiwifruit, significantly (P < 0.05) increased the Ca content and firmness, delayed the fruit ripening and softening, and enhanced the storability. Moreover, the kiwifruit soft rot was effectively controlled; the control efficiency was 61.68–88.79%. Additionally, the 28.6% CTS-Fh sprays significantly (P < 0.05) increased the content and activity of some defence-related secondary metabolites and enzymes, and could also increase the cell wall compactness in the kiwifruit. These results suggest that 28.6% CTS-Fh might trigger several defence responses in the kiwifruit against pathogenic infections. The doses of 28.6% CTS-Fh 200–400 dilution times were recommended for the practical application with regards to the production of kiwifruit.