Chitosan Augments Tetramycin against Soft Rot in Kiwifruit and Enhances Its Improvement for Kiwifruit Growth, Quality and Aroma

In this study, the co–application of chitosan and tetramycin against kiwifruit soft rot and its effects on the disease resistance, growth, quality and aroma of kiwifruit were investigated. The results show that chitosan could effectively enhance tetramycin against soft rot of kiwifruit with the field control efficacy of 85.33% for spraying chitosan 100 time + 0.3% tetramycin AS 5000–time dilution liquid, which was higher than 80.99% for 0.3% tetramycin AS 5000–time dilution liquid and significantly (p < 0.01) higher than 40.66% for chitosan 100–time dilution liquid. Chitosan could significantly (p < 0.05) improve the promoting effects of tetramycin on total phenolics, total flavonoids, SOD activity of kiwifruit compared to tetramycin during storage for 0–28 days and enhance the disease resistance of kiwifruit. Moreover, the co–application of chitosan and tetramycin was more effective than tetramycin or chitosan alone in enhancing fruit growth, improving fruit quality and increasing fruit aroma. This study highlights that chitosan can be used as an adjuvant to enhance tetramycin against soft rot of kiwifruit and promote tetramycin’s improvement for the single fruit volume and weight, vitamin C, soluble sugar, soluble solid, dry matter, soluble protein, titratable acidity and aroma of kiwifruit.