A strain H-2 was isolated by diluted solution method from soybean continuous cropping soil sample,its morphological,physiological and biochemical characteristics were identified and 16S rDNA was analyzed. The result showed that it was Streptomyces parvus. Fermentation filtrates of Streptomyces parvus at different concentrations were evaluated for nematicidal activity against Meloidogyne incognita and Rhabditis sp. in laboratory. Fermentation filtrates of the strains could suppress the egg hatching and 2nd-instar larvae of Meloido-gyne incognita. Culture filtrates of Strain H-2 showed a weak level of nematicidal activity of free-living Rhabditis sp. The corrected mortality rate of Meloidogyne incognita egg hatching and 2nd-instar larvae reached 74.35%and 78.46%,respectively by,strain H-2 at 5 diluted solution.

Snef 960 which have efficiency to induce anti-atrazine in soybean was screened from laboratory save strains.Cultivation medium of snef960 was researched by orthogonal experiment.The result showed that the optimal C/N ratio was composed of 4% glucose,0.6% NH4NO3,the optimal inorganic salts ratio was composed of 0.04% KCl,0.15% K2HPO4,0.04% MgSO4·7H2O,0.001% FeSO4.The culture conditions were screened with mono-factor test,and the most suitable technical parameters were summed up as follows: pH8 before sterilized,fementation time 9 d,agitation 180 r·min-1,volume 70/100mL,inoculated volume 10%.

It has been a new research focus on biological control that the induction of disease resistance and growth response in plants is elicited by plant growth promoting rhizobacteria(PGPR).This study aimed to examine the biochemical mechanism of the resistance to soybean cyst nematode(Heterodera glycines Ichinohe) in soybean induced by PGPR [Sneb207(Bacillus megaterium) and Sneb482(Bacillus megaterium)].Seed bacterization with Sneb207 and Sneb482 were utilized in the experiment.The soybean plants were inoculated with eggs of soybean cyst nematode after soybean trefoil stage and the samples of roots were obtained 6,12,18,24 and 30 days later.Activities of plant resistance correlated enzymes including defense enzymes,namely phenylalanine ammonia-lyase(PAL),polyphenoloxidase(PPO),peroxidase(POD) and chitinase were measured,the content of total phenolics was also determined.The results showed that both the activities of PAL,PPO,POD,chitinase and the contents of total phenolics could be increased significantly by seed coating with fermentation liquid of plant growth promoting rhizobacteria(Sneb207,Sneb482) in the soybean roots than those in control.Sneb207 showed greater potential in induced resistance against soybean cyst nematode in the soybean plants than Sneb482.

Fifteen organic acids from commercial sources were assayed against Meloidogyne incognita to compare their nematicidal activity.The LC50 parameter was applied to evaluate their nematicidal activity.The present study showed that formic acid and propanoic acid had the highest corrected mortality and incubation inhibition ratio,but the bioactivity of abamectin was better than that of formic acid and propanoic acid.Through analyzing compound structure and its bioactivity,we found that the compounds with small molecular volume had more excellent activity than the others.

The resistant and susceptible varieties of HuipizhiHeidou(ZDD2315) and Liaodou 15 were tested against soybean cyst nematode(Heterodera glycines,SCN).The plants were inoculated with eggs of SCN and the samples of roots were obtained 5,10,15,20,25 and 30 days later.The contents of MDA,soluble sugar and soluble protein in the roots were measured in order to reveal the physiological mechanism of HuipizhiHeidou resistant to race 3 of SCN.The results showed that the contents of MDA and soluble sugar in HuipizhiHeidou were less than that in Liaodou 15,and the content of soluble protein in HuipizhiHeidou was more than that in Liaodou 15 after inoculated with SCN.

The second stage juveniles(J2) and eggs of Meloidogyne incognita were treated with Fusarium strains to evaluate its nematocidal ability on Meloidogyne incognita.452 Fusarium strains were isolated by dilution from soil samples collected in Northeast and North China.14 Fusarium strains were obtained which were demonstrated to be with higher nematocidal activity against Meloidogyne incognita.The suspensions of strain Snef242 and Snef332 were significantly effective against the second stage juveniles(J2),the corrected mortality rate reached 91.99 and 91.35%.The fermentation filtrates of strains Snef332,Snef242 and Snef143 possessed effective with higher suppressive percentages of 86.61,86.19 and 85.36% on the hatching of egg capsuLe;The fermentation fi ltrates of strains Snef109,Snef332,Snef408 and Snef143 possessed effective against the second stage juveniles,and the strain Snef109 possessed the highest corrected mortality rate 94.70%.The strain Snef332 demonstrated to be with higher genetic stability and higher potential on controlling Meloidogyne incognita.

Strain Snea49,was isolated by diluted solution from a soil sample collected in Liaoning province.The results based on characteristics of morphological,physiology and biochemistry and 16S rDNA sequence analysis of strain Snea49 showed that it was Streptomyces anulatus.Fermentation filtrates of Streptomyces anulatus at different concentrations were evaluated for nematicidal activity against soybean cyst nematode in the laboratory,bioassays included egg hatching and mortality of second stage juvenile.The hatching rate of cysts were suppressed by 82.60% at 10× diluted solution.The corrected mortality rates of juveniles were 89.66% when J2 were treated with the strain at 1× dilution for 24 hours.The difference between these treatments and water control were significant.Fermentation filtrates of the strains were effective in inhibiting H.glycines hatch and killing J2.

Forty-two populations of Heterodera glycines were isolated from 22 counties in 14 cities in Liaoning province,China.According to the procedure of Golden et al,five differentials,Lee,Pickett,Peking,PI88788 and PI90763 were used to identify the races in 2007-2008.A map of race distribution was constructed according to the data from this experiment and literature cited.The results showed that a total of 14 samples could be divided into three races,including race 1,race 3 described previously and race 6,which first discovered in Liaoning province.Among them,race 1 was in Tieling;race 3 was found in Dalian,Panjin,Jinzhou,Benxi,Huludao,Fuxin,Anshan,Dongling District,Liaoyang,Dandong and Fushun,and race 6 in Chaoyang and Yingkou.However,race 3 distributed widely and was still principal race in Liaoning.

The resistant and susceptible varieties of Huipizhi Heidou and Liaodou 15 were tested against to soybean cyst nematode(Heterodera glycines,SCN).The plants were inoculated eggs of SCN after trefoil stage indoor and the samples of roots were obtained after the inoculation of SCN 5,10,15,20,25,30 d.The samples activities of plant resistance-correlated enzymes were mensurated including PPO(polyphenol oxidase),POD(peroxidase)and PAL(phenylalanine),and content of total phenolics and isoflavone were also determined,in order to reveal the biochemical mechanism of Huipizhi Heidou resistant to race 3 of SCN.The results showed that the activities of PPO,POD,PAL could be increased both in Huipizhi Heidou and Liaodou 15,and the fastigium of defense enzyme activities presented earlier in Huipizhi Heidou than Liaodou 15,the contents of total phenolics and isoflavone could also be increased in Huipizhi Heidou and Liaodou 15.