Resistant Mechanism Of Grape Fruit To Gray Mould Blight

Grape Gray Mould Blight is one of the most destructive diseases in grape production. This disease generally occurs in grape fields, but is more severe during fruits preservation. This disease leads to 20%-30% even 50% losses every year although there are effective fungicides and advanced preservation technique, which seriously affects the yield and quality of grape.The aim of this research is to reveal the correlation between the occurrence, development of Grape Gray Mould Blight under preservation condition and the microbial community structure and nutrient situation of grape fruits by analyzing the microbial microflora and some biochemical substances in grape fruits of resistant and susceptible varieties, in order to prevent Grape Gray Mould Blight during preservation of clusters by biocontrol or biochemical control. The conclusions are as follows:1.Resistance of different Grape varieties to Gray Mould BlightThe fruits of grape exhibited staggered resistance that is the resistance descends with the grape being ripe. Different varieties exhibited different resistance to Grape Gray Mould Blight. Variety Centenial Seedles is more resistant than Variety Red Globosity at young stage of fruits, but Red Globosity is more resistant than Centenial Seedles at ripe stage and during preservations of fruits. The resistance of fruits to Grape Gray Mould Blight changed with the preservation temperature. It was easier to be infected at 25℃than 0℃.2.Relativity between microbial community structure on/in the grape fruits and the occurrence of Grape Gray Mould Blight on fruitsMicrobial community and the amount on grape fruits changed with the growing stage. Bacteria and actinomycetes are the preponderant communities on young grape fruits. With the fruits being ripe, fungi gradually replacing bacteria and actinomycetes became the preponderance. There was certain correlation between the microbial community as well as its amount on grape fruits and the infection of Grape Gray Mould Blight. The more abundant the diversity of fungi , synchronously the less that of bacteria and actinomycetes, the easier the fruits be infected. We got one isolates of Botrytis cinerea from flower of grape, from then on, more and more Botrytis cinerea isolates were obtained and became the absolute preponderance.3.Relativity between Grape Gray Mould Blight and exudates of the grape fruitsSuperficial exudates of the grape fruits obviously promoted the spore germination of the Botrytis cinerea. There is high correlation between the promotion and the severity of Grape Gray Mould Blight in fields. Superficial exudates from the preservation fruits exhibited the strongest promotion to the spore germination, so the preservation grape fruits were seriously infected.