Research And Development, Resistance To Soybean Cyst Nematode Biological Seed Coating

Cyst hatching inhibition test carried out on the soybean cyst nematode from the recession of the land has been isolated from biocontrol strain, two strain with good inhibition effect on cyst hatching were screened out, which were Bacillus laterosporus BL-21 and strain HNDF2. Control effect of them on the cyst nematode were researched and the seed coating were developed and prepared with bacteria liquid for its application to agriculture.Studies on the bacteria infectivity on soybean root showed that strain BL-21 and HNDF2 belong to non-infected bacteria. The effect of bacteria liquid and metabolites of BL-21 and HNDF2 on cyst hatching and juveniles of Heterodera glyines was investigated. The result indicated that the mixture of bacteria liquid fermented with two Bacillus strains had better inhibition effect and on cyst hatching and lethality role on J2. Indoor pot experiment showed that control effect of mixed liquid on the soybean cyst nematode is better than that of any single strain.On this basis, the additive ingredients and formulations of soybean seed coating was researched with mixed bacteria as an active ingredient by single factor and orthogonal tests. The stability of the indospore quantity and the inhibition effect on Fusarium oxysporum were tested when additive ingredients was added in bacteria liquid, the adjuvant which can play protective role on activity of seed coating auxiliaries were selected as follows:film-forming agen J, K and L, dispersing and suspention agent A, carrier F. Seven different film-forming agent (L1-L7) were prepared according to the proportion of J, K, L. Through testing film forming, water-soluble, swelling properties, and drying time of the film former, three priscriptions, L2, L4, L5, were secreened for their significant physical properties. Therefore the first round of the orthogonal test was designed with L2, L4, L5 as film former while A as dispersing agent and F as carrier. The experiment demonstrated that film-forming agent had greater impact on seed germination rate than the others. L4 was selected for its largest K value to experiment with vector F and dispersing agent A by the second round of the orthogonal test. The best seed coating formulation was obtained for its remarkable seed germination rate, moreover, the addition range of various additives was suggested. Finally, through testing for the effective ingredient, pH value, viscosity degree, abscission rate, and indospore quantity, the biotype seed coating priscriptions was determined as follows: vector F 1.Og/L, film-forming L41.5g/L, dispersing agent A 1.0g/L.Field test results in past three experiment showed that control effect of seed coating prepared With Bacillus bacterium BL-21 and HNDF2 as the active ingredient on soybean cyst nematode was good. Compared with the commonly used chemical seed coating, Control effect of 4% bacillus seed coating were 29.21%,63.69%,53.80%, respectively, better than that of 35% Carbendzim-Carbofurum-Thiuram seed coating, and its stability is good.