Studies On The Grape Fruit Rot In Shihezi Region

Seriously grape fruit rot took place in Shihezi region 2008. Not only many grape yards were led to no harvests, but the product of the grape was heavily impacted. To determine the main pathogens of grape fruit rot, typically rotten grape fruits were collected and isolated to be identified by morphological and molecular methods. The pathogens cause grape fruit rot were identified as Botrytis cinerea, Aspergillus niger and Rhizopus nigricans. The main pathogens of grape fruit rot in Shihezi region were determined and the inducing reason was found to relate to the rains after long drought of the first ten days of August and the redundancy of hormones dosage.The biological characteristics of the pathogens were observed under different conditions such as different temperatures, pHs, lights and mediums. The temperature for mycelia growth of B. cinerea Pers. was from 5℃to30℃, with the optimum 20℃;the pH values ranged from 3 to 9, with the optimum 5; The temperature for mycelia growth of A.niger was from 5℃to35℃, with the optimum 30℃; the pH values ranged from 3 to 9, with the optimum 6; The temperature for mycelia growth of R. nigricans was from 5℃to35℃, with the optimum 30℃; the pH values ranged from 3 to 9, with the optimum 5. Red earth, Munati and Jufeng were obviously resistant to the strain Botrytis cinerea and Aspergillus niger. But the purple seedless was merely resistant to all the three strains.Studies on the pathogen variation of different Botrytis cinerea strains from different hosts: grape and cotton. It was concluded that both of the different sources strains had the same suitable growth temperature at 20℃. Light environment variations had no effect to the strains. Strains came from grape and cotton had nearly the same growth velocity. Grape Botrytis cinerea's sclerotium were bigger than cottons'. Genetic variations are among the grape and cotton Botrytis cinerea through the RAPD analysis.RAPD assays showed that 4 out of 8 random primers could amplify the template DNA (genomic) extracted from the 10 isolates of Botrytis cinerea. The tested strains had abundant genetic diversities. With the genetic similarity coefficient 0.37 as the threshold, the 10 Botrytis cinerea strains were classified into four cluster groups (ⅠⅡⅢⅣ) according to the DNA spectrum of primer amplification. GroupⅠwas composed of two srtains from grapes in shihezi. GroupⅡcontains three strains from cottons in shihezi. GroupⅢcontains two strains separately from grape and cotton in shihezi. Srtains in groupⅣwere isolated from grape and cotton of Yili Bole and Alaer region. There was certain relationship between the classification of cluster groups and the sources and hosts of strains.