小麦纹枯病拮抗细菌的筛选

 从小麦纹枯病病田土壤中分离到722株细菌,通过对峙培养法筛选出拮抗细菌397株,拮抗菌率为55.0%。细菌对小麦纹枯病病原菌的拮抗作用分为两种类型:其一以竞争作用为主,表现为菌株生长快,抑菌率高但抑菌带较窄,如菌株BNT-25抑菌效果可达100.0%,抑菌带仅为2 mm;其二为抗生物质的产生,表现为菌株生长慢,菌落小,抑菌率高且抑菌带宽,如JJ-5菌株抑菌效果可达94.3%,抑菌带为12 mm。选用18株抑菌作用良好的拮抗细菌在室内测定其防治小麦苗期纹枯病的效果。结果发现,与空白对照相比,有9株拮抗细菌的防治效果达到了极显著水平,有15株拮抗细菌的防治效果达到了显著水平。在极显著水平中菌株NZT-47、MTT-8和DHT-12的防治效果分别为76.45%、64.03%和58.89%,对小麦纹枯病表现了较高的防治效果;菌株HNT-7-16、BDT-94和BNT-28的防治效果分别为43.47%、40.97%和40.97%,具有一定的防治作用。其中NZT-47的防治效果最好。

Isolation, screening and bioassay of antagonistic bacteria against wheat sharp eyespot

722 strains of bacteria were isolated from the wheat field infected by Rhizoctonia cerealis, pathogen of wheat sharp eyespot. Among them, 397 strains bacteria were antagonistic to R. cerealis in dual culture test. The rate of antagonistic bacteria is 55%. The main action mechanisms of antagonists were competition and antibiosis against the pathogen. The bacteria with competitive function showed quick grew and high antagonistic rate, but narrow inhibition zone. Strain BNT-25, for example, its antagonistic rate reached 100. 0% , but inhibition zone wais only 2 mm. Another type of bacteria with antibiotic function showed strong inhibition and slow growth. Strain JJ-5, for example, the antagonistic rate reached 94.3% , and inhibition zone was 12 mm. 18 bacterial strains with strong antagonism were selected to control wheat sharp eyespot at seedling stage in growth chamber. 24 bacterial strains showed significant control effects against the disease. The control effects of strains NZT-47, MTT-8 and DHT-12 were relatively high, 76. 45% ,64. 03% and 58. 89% , respectively. While that of others such as strains HNT-7-16.BDT-94 and BNT-28 were 43. 47% ,40. 97% and 40. 97% , respectively. The control effect of strain NZT-47 is the best.