Study On The Invasive Characteristics And Antagonists

According to the different growth periods over rice field, the experiment was conducted by bagging treatment when the ligule of flag leaf and the top second leaf are just of overlapping. The factors influencing incidence rates of rice false smut were studied and optimized with orthogonal design by means of artificial inoculation on field. The test were using different inocula(mixture of hypha-fragment and conidia,hypha-fragment,conidia and chlamydospore) of false smut pathogen(Ustilaginodea virens) to inoculate rice of different growing stages(the 10d,7d,4d before emergence of panicle,the rupturing stage of rice,) by distinct of inoculation methods(injecting, spraying and dripping irrigation),but using different inocula in distinct inoculation methods on panicle initiation and panicle trim. there is a significantly affected with the incidence of disease by inoculated period,but inoculation methods and inoculated stage dont.The results showed that the optimal vaccination period, the best method of inoculation and vaccination pathogens thalli were as followed:for the high incidence of disease on the before 4 days of crevasse when mixture of hyphae and conidia were inoculated by injecting. The optimum percentage of disease grains was 13.75%. The optimum percentage of disease grains were zero on the panicle initiation and panicle trim. It provides applied basis for studying on the infection period and the infection gate of Ustilaginoidea virens on rice.The test indicated that both the growth of hypha and sporulation ability were the strongest when Ustilaginoidea virens trained 10d. spore germination was more than 80% at 24h by the activity experiment. The experiments proved that yellow thick wall of spores energy than green spores when they were held a year for the artificial respectively.But the yellow spores germination was very weak,the biggest quality was 6.42% at 48h.One hundred and sixty-six bacterial isolates were isolated from 95 rice samples of stalk,leaf and sheath,soil,unhealthy seed and healthy seed of the same rice variety collected at the different growing stages, The study on the relationship between the total bacterial number and antagonists in different growing stage showed that in general,in stalk,leaf and sheath,soil,the total bacteria number was the highest on the tillering stage and then decreased with the rice mature. In unhealthy seed and healthy seed,the highest number at the dough stage and then increase with the rice mature.The soil supported the highest bacteria number in the different samples,and the percentage of antagonists was the highest in soil.It showed that three bacterial isolates,1.81% of total,were antagonists when screened for antagonists against Ustilaginoidea virens by controlling fungus and liquid culture,the number isⅢ-A9,III-B1,Ⅲ-B31.Ⅲ-B31 was the strongest against the pathogen among them,Ⅲ-A9 was the lowest,the inhibition rates of the metabolites of these two strains were 78.95% and 49.12% in petri dishes,respectively.Three bacteria were aerobium and Gram positive by identification.Rhabditiform of cell,having spore and flagellum.So they were Bacillus by identification preliminary.By single factor experiment,the liquid fermentation mediu of the three bactria were optimizd.It showed that there is a significantly affected with bacteria amounts by the time,temperature,inoculation amount and pack amount.The favorable fermentation condition was determind:time 36-48h,temperature 28～30℃,inoculation amount 3%,pack amount 100ml/500ml triangle bottle.The test results indicated that the fermentation effect obvious of the growth of hypha,and cused Ustilaginoidea virens can not form hypha-ball.The population is on the birth of spore germination suppression rate as high as 92.47%,the chlamydospores of Ustilaginoidea viren inflation rate is 88.61% byⅢ-B31,and the lowest byⅢ-A9.