Study On The Relationship Between Wheat Scab And Corn Stalk Rot In Sichuan Province

Wheat and maize are two kinds of important food crops and cash crops. However, in their whole growth period, they often suffer from a variety of diseases and insect pests which have serious influence on the two crops yield and quality. Wheat scab and maize stalk rot is a worldwide epidemic diseases, Fusarium spp. is the main source of pathogens, causing two diseases in Sichuan. It’s necessary to make some researches on the Fusarium spp. which case the two kinds of disease.To explore the relationship between two kinds of Fusarium infection diseases, this test from the natural infection investigation, species identification and pathogenicity to do the research. Tests of wheat field natural disease investigation have been down in Chengdu, Ya’an, Mianyang and other 13 different ecological types of wheat planting region in Sichuan province. At the same time, collecting pathogens of wheat scab and maize stalk rot by tissue separation and direct single spore isolation. We collected 499 samples of wheat scab and 164 samples of maize stalk rot pathogens, saved 99 strains of wheat scab,94 strains of maize stalk rot through separation and purification. By observation of morphology and culture characters, including characteristics of colony, colony growth rate and spore form, carries on the preliminary classification, identification and selection of typical strains by molecular biology methods.respectively, of rDNA ITS area and elongation factor sequence to construct phylogenetic trees, analysis homologous, further clarify classification status.Results show that the 99 strains come from different areas of wheat can be identified as 3 classes which are Fusarium graminearum, Fusarium asiaticum and Fusarium avenaceum.94 strains of maize stalk rot can be identified as 5 categories. Fusarium proliferatum, Fusarium kyushuense, Fusarium verticillioides, Fusarium equiseti and Fusarium graminearum.72 plants Fusarium asiaticum has been found, accounted for 72.73% of all strains, as the superiority strains; 27 Fusarium proliferatum strains of maize stalk rot, taking up 28.72% of all strains and becoming the strain for advantage. The strains colony characteristics, colony growth rate and conidium morphology show some differences, demonsrtating the pathogen has rich diversity in morphology. By analysising the phylogenetic trees of rDNA ITS and EF-1 a two sequences, the results show that two kinds of sequence all can clustering and identification results in line with the morphological identification results. Both the phylogenetic tree can effectively reveal thephylogenetic relationship, but the intra-specific genetic differentiation reveals the weaker. Compared with fungi rDNA-ITS regional general primers ITS1 and ITS4, identifying specific primers EF-la with EFIH and EF2T amplification specific fragments of different sizes, more accurately the difference between different species.To investigate whether two diseases pathogen infect across the host, first, we desigined experiments on investigation about the field of natural infection situation on different wheat and maize stalk rot cultivation pattern; Second, selected on the identification of the heavy wheat and maize stalk rot pathogen of Koch’s rules for typical representative strains selected validation and interact vaccination pathogenic study. The results showed that straw counters-field wheat-maize interplanting mode induce two biggest disease rate is highest, relative productivity; Straw no-returning the net for the lowest incidence of wheat/maize and relative productivity, different dominnate Fusarium spore strains were successfully interaction infection, but the pathogenic ability exists obvious difference. Thus it can be seen that the metabolism Fusarium spp. causes wheat scab and maize stalk rot has a certain relevance and difference. Under certain conditions, the two interaction can infect, sick body field plants can be used as the initial source of pathogen and cause pathogenic infection across the host. Wheat-Maize interplanting free of cultivated land area in Sichuan, wheat scab and maize stalk rot may appear increasingly serious trend.