Studies On Pathogens And Resistance To Common Root Rot And Crown Rot On Winter Wheat In Northwest,China

Common root rot and crown rot are common diseases in wheat production.There are reports on these two diseases in the production and planting areas where wheat is the main grain.These two diseases are widely distributed in the world,and all areas where wheat is grown have occurred to varying degrees,resulting in reduced wheat yield and quality,posing a serious threat to economic efficiency and ecological security.In recent years,the occurrence of common root rot and crown rot has been aggravated in the winter wheat region of northwestern China,and its prevention is imminent.This study was based on the identification of the pathogens of common root rot and crown rot in winter wheat in Northwest China,combined with the pathogenic ability of pathogenic bacteria,screening of germplasm resources,screening of indoor chemicals,and toxicity testing.Common root rot and crown rot were studied.It will lay a solid theoretical foundation for the in-depth study of common root rot and crown rot of winter wheat,its development of resistance breeding,and scientific prevention and control of the disease.The main research results of this study are as follows:1.Improve the disease symptoms of common root rot and crown rot in the northwestern region:?1?Common root rot can occur during the whole growth period of winter wheat.Seedling stage seedlings dry,adult stage formation of root rot,leaf dry,black embryo,plexiform white ear and other symptoms.Symptoms often vary due to climatic conditions,and root rot symptoms often appear in arid and semi-arid regions.In moist areas,in addition to the symptoms of root rot,leaf blight,ear dryness,black embryos and other symptoms can also occur.?2?Crown rot is complicated when it occurs on winter wheat.It mainly includes rotten seed,dead seedlings,browning of the stem base and symptoms of single plant white spikes.The symptoms of seedling stage showed patchy disease in the field.The growth of seedlings was weak and the leaves were yellow.The adult plants showed sporadic white spikes in the field,and irregular lesions formed on the stems and even the stems of stems.A white or pink mold layer can be seen on the leaf sheath.2.The fungus was isolated by conventional tissue isolation method.The strains were isolated by single fungus purification by fungal purification,followed by Koch's rule for the determination of pathogenicity by the small beaker method.Combined with morphological features,microscopic features and three kinds of molecular biological identification?LSU molecular identification,ITS molecular identification,TEF molecular identification?the pathogens were identified.The results showed that the dominant pathogenic cause of common root rot of winter wheat in Northwest China was Bipolaris sorokiniana.There are 9 pathogens causing crown rot in winter wheat in Northwest China,including Fusarium pseudograminearum,F.culmorum,F.equisteti,F.tricinctum,F.redolens,F.oxysporum,F.proliferatum,F.nygamai,F.subglutinans.Among them,F.pseudograminearum,F.redolens,F.nygamai,F.subglutinans as the pathogens of crown rot of winter wheat were first reported in Northwest China.3.Using a small beaker method to identify the resistance of 38 wheat germplasm resources that were popularized in Northwest China.The results showed that among the38 wheat varieties tested,no wheat varieties immunized against common root rot and crown rot were found.In the resistance test to the pathogen of common root rot,no resistant varieties were found,and all the varieties showed a susceptible variety or a high-sensitive variety.The results of the inoculation of stem rot pathogens showed that the three varieties of Lan 15,Lantian 131 and Lantian 132 showed resistance to the pathogenic fungi of the tested Fusarium,and the resistance was strong.Lanxuan 68,Lan Hangxuan 121,Zhongliang 34,Longjian 101,Longjian 107,Dongyu 4 and other varieties were susceptible or susceptible to most pathogens tested.4.The results of screening of indoor chemicals test carried out in this study showed that 98%carbendazim had good inhibitory effect on 2 strains of Fusarium strains,but the inhibition rate was 100%,but the growth inhibition rate of H.umbellatus was not good.The antibacterial rate of 96%King Copper to Fusarium was very low,about 20.00%,but the antibacterial rate of Helminthosporium meliloti was nearly 70.00%.98% difenoconazole had good antibacterial effects on the three strains.98%carbendazim had the smallest EC₅₀ value of 7.03?g/ml,which had the greatest inhibitory effect on the growth rate of Fusarium.