Study On The Occurrence And Critical Technology Control Of Soybean Root Rot

Soybean root rot is a kind of worldwide serious disease,one of the destructive diseases, affecting soybean production.The disease mainly distributed in the Northeast and the Huang-Huai region in China. Soil-borne is an important mode of transmission of the disease. The disease can lead to reduce ten to thirty percent of soybean production in generally,sixty percent in serious illness region,even total destruction! In recent years,with increasing the status of soybean continuous cropping,root rot become more and more serious,seriously affecting the yield and the quality of soybean.The surveys and studies on the occurrence of root rot of soybean,infection dynamics,etiology,pathogen biology,pathogenesis and control of disease resistance were carried out in the main soybean growing areas in Burqin County of Xinjiang. The results showed local soybean root rot resulted from Fusarium oxysporum [including Fusarium oxysporum variants Fenfang (Fusarium oxysporum var.vodolens),Fusarium solani rot (F.solani (Martium) App. et Wr.) , Fusarium graminearum (Fusarium graminearum Schw) Fusarium and oat (F.aveneum (Fr) Sacc)],Rhizoctonia solani (Rhizoctonia solani KÇ–hn) and the Pythium aphanidermatum.The local dynamics of the three major pathogenic features were identified respectively. (1) Rhizoctonia solani infected the seedling early in the fields, and was isolated in high frequence. Marks of these diseases were beneficial to Fusarium infecting the seedling. We speculated soybean root rot origined from Rhizoctonia solani. (2) Though Fusarium began to infected the plant from the seedling stage,the proportion of it infected plant was lower than Rhizoctonia solani.With the passage of the soybean growing period,the damage of Fusarium trended to strengthen.Throughout the reproductive period,Fusarium was isolated in high frequence.That is,Fusarium is the major factor of the occurrence of soybean root rot. (3) Pythium resulted in black species and bud black before the seedlings, led to seedling damping-off and dead during the seedlings;but it was separated in the lower frequency.We deduced Pythium was the minor factor in root rot occurred. The determination of the Varieties (lines) resistance to disease showed: three soybean varieties and three lines were significant differences in root rot resistance,but they were no highly resistant varieties;Relatively speaking,HEIHE 26 had relatively good resistance characteristics.Against root rot of soybean seed treating drug,the results showed that: three kinds of seed coatings (Vitavax,Thiuram-Carbofurum,Carbendzim-Carbofurum-Thiuram) can effectively inhibit these disease from infecting seed early. In addition,good seed coating was a key measures of the prevention and control of soybean root rot.Besides,through the fungal genomic DNA section of the ITS restriction enzyme analysis;the molecular markers of three pathogens (Fusarium oxysporum,Rhizoctonia solani and Pythium.spp) had been established;and through multi-sample validation of mixture strain molecular detection of pathogens, a wide range molecular detection technology of pathogen to separating fungi from mixed samples is established. Compound pathogen infection dynamics of molecular detection and tracking complex infection,in order to further study this disease laid the foundation.