Preliminary Study On The Detection And Molecular Identification Of Muskmelon Seedborne Fusarium And Seed Treatments

Ten main cultivars sown in Heilongjiang and Jilin provinces were used in this paper to detect the seedborne fungi and to isolate Fusarium. Fusarium sp. was isolated from seed coat of muskmelon seeds (cv.Tedalvmagua), and the fungi was named Fusarium-TD. The morphological observation and molecular identification of the fungi were conducted. The effect of spore suspension of Fusarium-TD on seed germination of muskmelon seeds and its pathogenicity were also carried out. Moreover, inhibition effect on the Fusarium-TD of five fungicides and its disinfention effect and safety on the seed germination were studied. The results obtained in this paper are as follows:1. Penicillium, Rhizopus, Aspergillus, Alternaria and Fusarium et al. were muskmelon seedborne fungi; After conducting the morphological observation and molecular identification of Fusarium-TD, the fungus is Fusarium oxysporum. To the best of our knowledge, it is the first report of seedborne Fusarium oxysporum isolated from seedcoat of muskmelon seeds in China.2. The germination energy, percentage germination and germination index of muskmelon seeds decreased after treated by spore suspension of Fusarium-TD which showed the Fusarium had harmful side effects on seed germination. Compared with control, after treated by spore suspension of 105 conidia/mL and 106 conidia /mL of Fusarium-TD, the germination energy, percentage germination and germination index of muskmelon seeds significantly decreased. Pathogenicity of Fusarium-TD was studied using radicle-dipping inoculation method and primary results showed that the Fusarium-TD is pathogenic.3. All the four fungicides tested have inhibition effect on the Fusarium-TD except Metalaxyl, effect of Fludioxonil are better than the other chemicals.The percentage of seedborne fungi decreased when treated using the five chemicals. In the chemicals tested, the disinfection effect of Fludioxonil and Thiam were over 80%. After seeds treated by them, germination energy, percentage germination of muskmelon seeds were not significantly different between control and treatments, which shows the germination of muskmelon seeds after treated by the fungicides was safe.