| In this paper, the ecological facts, varieties resistance, fungicides screening, the change of biological and biochemical indexes in different resistant rice varieties after inoculation with Fiisarhim moniliforme, biocontrol of rice bakanae disease and inheritance of pathogenic resistance to cabendazim and prochloraz were studied in details, respectively, and the results were as following:By soaking rice seeds in spore suspending liquid and investigating the disease incidences during three-leaf period,The result showed. Sprouting period was the most suitable period for disease occurring.Relation between disease incidence and soaking temperature was positive correlativity(The correlative coefficient was 0.8757) and the correlative coefficient between disease incidence and sprouting temperature was 0.9570 during the scope of 28℃~34℃. And the most effective sprouting temperature was 34 ℃ .In addition, the most appropriate inoculation time in soaking and sprouting period was 18h, 24h, respectively. Moreover, "buds equal the length of one rice seed " phase was the most suitable phase for F. moniliforme inoculation.The cluster analysis of 17 rice varieties resistance to bakanae disease in Anhui was studied with the longest distance method. The results showed that 17 rice varieties could be divided into 5 groups, and varieties of the same resistance had been fell into the same group in the pedigree figure. Class I was basically resistance varieties. There were three sub-groups in varieties of class II,which mostly were middle-resistance varieties.That is: 1 and 12 was the same sub-group , belonging to more resistant varieties;3 and 17 was the same sub-group ,more susceptible ones; and 6,10,15 formed another sub-group , middle-resistance varieties. Class III and IV were middle-susceptible varieties, then the last class V was susceptible ones. They could be chosen in disease resistance in varieties breeding or the distribution of different resistant varieties. The result of dividing 17 varieties into 5 groups was coincident with the facts. It could also be used in guiding disease resistance in breeding or the distribution of different resistant varieties.Making use of inhibition of different fungicides against F. moniliforme mycelial growth and conidial germination, toxicity determinations of single and mixed fungicides in controlling rice bakanae disease had been done. The results showed: With regard to single fungicides, the inhibitions of Sportak,Prochloraz and Scelartial were more significant than the rest.EC50 of inhibiting mycelial growth was 0.1473 ug ml-1, 1.4645 u g-ml-1 and 9.2445 u g·ml-1 respectively. And inhibiting conidial germination EC50 was 0.9842 ug · mL-1, 3.7574 u g · ml/-1 and 0.8041 u g · ml/-1, respectively. With regard to mixed fungicides, the effects of "Sportak+ Chlorothalonil" and "Prochloraz+Scelartial" were the best. EC50 and CTC of inhibiting mycelial growth were 0.0296u g·ml-1, 0.1419 ug·ml-1 and 993.82, 1781.85 respectively. EC50and CTC of inhibiting conidial germination were 0.0597 u g·ml-1, 0.0512 ug·ml-1 and 3253.19, 1728.50 respectively.By means of inoculation with F. monififorme at the stage of "the length of budding equals that of one seed", gibberellin contents in three rice varieties, which have differentresistance against rice bakanae disease,were studied.The results showed:gibberellin contents in all varieties increased obviously after inoculation. Moreover, the difference of gibberellin contents among different resistance varieties was significant. Gibberellin increasing rate in susceptible varieties was higher than that in resistant ones after inoculation. At the stage of budding, gibberellin increasing rates in Wanjing97, Zaoxian240, and Xieyou57 were 9.27,3.89 and 0.033, respectively. There was positive relation between the content of GA3 and disease incidence, and the linear equation was y=19.173x-69.439(F=1.17). What's more, at the stage of seedling, the increasing rates in rice leaf were 1.28,0.47, 0.13 respectively, which w...
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