Idenification And Biological Characteristic Of Wilt Pathogen Of Bambusa Pervariabilis×Dendrocalampsis Daii

Bambusa pervariabilisxDendrocalampsis daii,is a new hybrid bamboo, which was cultivated and screened by the researcher who spent many years on study at Forestry Institute of Guangxi.It has many advantages,such as high-yielding bamboo shoot, productive bamboo, large diameter,good performance of Bamboo and so on. The hybrid bamboo was listded as one of the100key promotion programs of Department of Forestry in1993, and it was promoted quickly as important planting bamboo species during the period of the Project of Land Conversion in southwest China after1999. At the beginning of introduction, the large number of the bamboo were cultivated, which brought economic, social and ecological benefits expected. However, the death of Bambusa pervariabilisxDendrocalampsis daii in a whole area brought serious economic loss in some regions in recent years, and many farmers turned to cultivate other species of bamboo or trees because the bamboo disease was not effectively controlled.So the sustainable development of Bambusa pervariabilisxDendrocalampsis daii industry faced serious challenges.At present, there are few reports about research on Bambusa pervariabilisx Dendrocalampsis daii blight in Sichuan. In this paper we choose the blight bamboo in Pengshan located in Sichuan province as the research object. In order to provide a theroretical basis for further prevention and control to the hybrid bamboo blight, we make researches about the morbidity situation of the hybrid bamboo blight, fusarium wilt pathogen, the biological characteristics of the pathogen, pathogen-pharmaceutical tests,et. And the main results are as follows:1. According to the investigations in July2010and April2011, there are different degrees of hybrid bamboo blight in the main planting areas in Jiangkou town and Gongyi town in Pengshan.The bamboo leaves turn red at the early period of disease,like fire,then dry-fall.And the bamboo culms turn yellow early, reddish-brown later or corrugate.It die finally.The results on the three plots shown that the disease indices all were above50. 2. In the process of isolation and identification of pathogen, we draw the following conclusion:firstly, according to the results of morphological features of the pathogenic strains and pathogenicity tests, the pathogenic bacteria is confirmed as the Fusarium,whose morphological characteristics is similar to the Fusarium oxysporum. Further research of the pathogen by molecular biology to amplify the DNA sequence of obtained strains with the fungi general primers ITS1and ITS4, the result suggestes that the length of the sequence is about520bp. The Homology search showed the ITS sequence of the diseases have high homology with the Fusarium Oxysporum, which are about99%. The phylogenetic analysis indicated that except for BDFOPS5, the other10strains are in the same branch with the Fusarium Oxysporum, and the creditability is99%, which proceed to show that the pathogen is Fusarium Oxysporum,consisted with the conclusion of research on Ma Yingling.3. Researchs on morphological feathure of pathogen showes that mycelia of the pathogen BDFOPS3grow fastest on OA medium, the diameter of the colonies reaches8.2cm after6days, and it produces most spores on CMA medium, about7.5×106per petri dish after10days;the light has no effect on mycelia growth, but the spores production show a significant difference whether in light or not, the production is lowest in continuous light, only7×105per petri dish, and the light can stimulate the pathogen produce pigment. With the strengthening of light intensity, zonal characteristic gradually formed in the positive middle of the colony. The temperature for mycelia growth ranges from8℃to36℃,the optimum growth temperature is24℃, The pH ranges from3to12,and the optimum pH is6;the lethal temperature of mycelia is64℃;carbon and nitrogen sources which is most suitable for mycelia growth is maltose and peptone,and the most suitable condition for spores germination is sucrose and yeast extract; the temperature for conidial spores germination ranges from15℃to35℃, the optimum is20℃; The pH for conidial spores germination ranges from3to12, the optimum is from6to8. The light has no significant effect on conidial spores germination, the germination rate both reach to90%under Illumination (12hours a day)or in darkness; conidial spores do not germinate when the humidity is below90%;the lethal temperature of conidial spores is also64℃as the mycelia.4.The results indoor fungicide tests show that prochloraz,chlorothalonil,mancozeb, methyl sulfates pirit, thiram, triadimefon and hymexazol had strong inhibitory effect on pathogen, and prochloraz got the highest toxicity, and then is chlorothalonil.