Postharvest Diseases Of Blueberry And Its Prevention

Blueberries belong to the rhododendron family(Ericaceae),the genus cranberry(Vaccinimu)plants.Blueberry is one of the 5 species of healthy fruits with unique flavor and high nutritional value.Blueberries are seriously infected by the postharvest diseases,which reduces their commerciality and hinders industrial development.It is particularly important to systematically study and control postharvest diseases of blueberries.Therefore,finding an effective method which is safe and environmental friendly has become an urgent issue to be solved in the current development of the blueberry industry.In this study,the pathogens of postharvest blueberry were isolated and identified,and a strain with high biocontrol efficacy on postharvest Botrytis cinerea and Alternaria spp.of blueberry was isolated from blueberry fruit.It was identified as Metschnikowia pulcherrima T-2.A preliminary study on the safety of T-2 and its inhibitory effects on the postharvest Botrytis cinerea and Alternaria sp.,and the efficacy on storage performance of blueberry at room temperature was carried out.The main results are as followed:1.A total of five pathogenic fungi were isolated from postharvest blueberry fruits by tissue separation,respectively are Botrytis cinerea and Cladosporium cladosporioides,Alternaria alternata,Penicillium expansum,Alternaria tenuissima.Among them,Botrytis cinerea and Alternaria sp.were the main pathogenic fungi of postharvest blueberry.2.Biocontrol yeast strain isolated from blueberry fruits that has good storage and freshness retention efficacy on postharvest blueberries,named T-2.It was identified as Metschnikowia pulcherrima.It was evaluated for safety and proved to be safe and non-toxic.3.The non-volatile substances of strain T-2 have no direct inhibitory effect on the hyphae growth of Botrytis cinerea and Alternaria sp.,but can affect the hyphae growth of Botrytis cinerea and Alternaria spp.through competition.Compared with the control group,the volatile substances produced by T-2 soaked blueberries can reduce the natural decay rate of blueberries by 40% at room temperature.4.The mechanism of T-2 inhibiting blueberry postharvest diseases includes the following aspects: T-2 can quickly colonize the wound of blueberry fruit at 4℃and 20℃,and compete with the pathogen for nutrition and space;T-2 can make blueberry fruits better quality,thereby extending shelf life;T-2 can improve defense-related enzyme activities suchas peroxidase(POD),superoxide dismutase(SOD),phenylalanine ammonia lyase(PAL)and catalase(CAT),enhancing the disease resistance and storage stability of fruits.