Study On The Biological Characteristic,Mycelial Compatibility Group And Genetic Diversity Of Sclerotinia Sclerotiorum In Heilongjiang Province

Sclerotinia stem rot disease is one of the main diseases of soybeans, the soybean sclerotinia stem rot disease have been reported at the domestic and overseas in recent years. Especially in Heilongjiang province which is the one of major soybean producing areas of China. The pathogen of soybean sclerotinia stem rot disease in soybean is Sclerotinia sclerotiorum (Lib.) de Bary, it is reported that S. sclerotiorum have considerable heterogeneity, and complex heredity types. The67isolates of S.sclerotiorum in soybean which be collected from different locations in Heilongjiang province were tested about biological characteristics, mycelial compatibility and genetic diversity. The aims to address the genetic diversity of different regions of Heilongjiang province on S.sclerotiorum in soybean, to provide a scientific basis of prevention and to effectively control the occurrence and extension in further research.In this article, the67strains from different locations of Heilongjiang province were cultivated by PDA medium, observe the colony morphology of strains, mycelial growth characteristics to classify, compare different strains producing sclerotia morphological features, such as size, shape and weight comprehensive analysis of the difference of strain morphological features in the biology. The experimental results showed that there are significant difference on the morphological features between strains, colony color into white, yellow and dark grey three types, the largest proportion accounted for49.3%is the yellow hyphae; hyphal fullness degree including three kinds, low fullness degree strains group population have more than half; only a few strains colony are irregular shape, the colony of remaining strains are round; sclerotium diameter between0.2～0.3cm have heavier grain weight. Heilongjiang province ecological climate type is complex, the distance between soybean area the geographical position. With the increase of geographic space, mycelium and sclerotium morphological differences increased. Through analysis of variance, different strains formed sclerotia number and weight are differences significantly (P<0.001). In the biological characteristics test of67strains from different collection locations in Heilongjiang province, the optimum temperature for mycelial growth is25℃; when the pH=6, the mycelial growth rate is highest, Alkaline conditions is not conducive to the hyphal growth; Sclerotium optimum germination temperature is15℃to25℃,20℃culture conditions conducive to sclerotium germination, The sclerotium germination and mycelial growth are no sensitivity to light.We used the mycelial compatibility technology to test mycelial compatibility groups of67samples of S.sclerotiorum in soybean. The result shows that the67strains which from different regions were divided into30MCGs through antagonistic experiment, including21strains in independent MCG, strains from different collective regions belong different MCGs, some strains from the same collective place in one MCG, others belong different MCGs. S.sclerotiorum strains exist larger heterogeneity, collective location and MCG have no correlation. The Heilongjiang province areas are vast, the mycelial compatibility groups have large quantity, and the complexity of the pathogen genetic type of S.sclerotiorum in soybean is high.To study genetic differences between strains by SSR molecular marker technology, and combining mycelial compatibility test to analysis the genetic diversity of strains.10for SSR primers have39characteristic bands,it has account for73.58%of the total number of bands, there are average5.3characteristic bands be amplified per each pair of primers. We got conclusion from clustering analysis diagram (UPGMA):it has obvious genetic diversity of soybean sclerotinia stem rot disease in Heilongjiang province, genetic type of S.sclerotiorum in soybean is complex, and the results exists consistency with the mycelial compatibility test. In Heilongjiang province, the pathogen genetic type of S.sclerotiorum on soybean is complicated, with the distance increase of soyabean area, the strains difference of S.sclerotiorum is increase, the complexity of the fungi genetic structure of S.sclerotiorum is high.