| wheat sharp eyespot,mainly caused by Rhizoctonia cerealis,is a serious soil-borne disease in wheat production.The number of sclerotia in soil is one of the important criteria for disease occurrence and epidemic.A selective medium for isolation of pathogens under non-sterile conditions was developed by mycelium growth rate method.The selective medium was based on Water agar medium（WA）,and added streptomycin sulfate,doxodine and carbendazim.The appropriate concentrations of three agents were 100μg?m L-1,1μg?m L-1and 50μg?m L-1,respectively.Selective culture medium could effectively inhibit the growth of Penicillium expansum,Rhizopus stolonifer,Alternaria tenuissima and Aspergillus niger,but had little effect on the growth of R.cerealis.;selective medium can be used to detect the sclerotia of R.cerealis in soil,and the recovery rate is about 80%.The selective culture medium for isolation of R.cerealis from the stem of infected wheat and can be operated directly in non-sterile conditions;selective medium can be used to detect the sclerotia in soil,and provide some reference for predicting the occurrence and prevalence of wheat sharp eyes pot.In order to systematically study the diversity of endophytic fungi in root and stem of wheat and select the biocontrol strains which can inhibit R.cerealis and Fusarium pseudograminearum,healthy wheat plants were collected from 22 counties and districts of 14 prefectures and cities in five farmland types of Henan Province in 2017 and 2019.The endophytic fungi of wheat root and stem were isolated by tissue separation method,and the isolates were identified by combining morphological characteristics with molecular identification,and the diversity of stem and root endophytic fungi of wheat of different farmland types was analyzed.The results showed that 426 endophytic fungi contained 23 genera and the dominant species were Chaetomium sp.,followed by Penicillium sp.、Rhizopus sp..The colonization rate and isolation rate of endophytic fungi in wheat were 24.36%and 25.71%on average.The colonization rate and isolation rate of endophytic fungi in wheat root of the same farmland type cultivation area were 2.56～5 times and 2.23～5.25 times than that in stem.The species of endophytic fungi in stem are less abundant than those in root;the diversity of endophytic fungi in different farmland types is different;the fungi of the same genus can be isolated from samples in different regions.Endophytic fungi of 7 growth periods healthy wheat were collected from the experimental field of Henan University of Science and Technology.The results of identification and diversity analysis showed that 144 strains of endophytic fungi were isolated,including 19 genera,among which the dominant populations were Penicillium sp.,followed by Rhizopus sp.and Chaetomium sp..The colonization rate and isolation rate of endophytic fungi were the highest in the mature period of wheat,respectively were 76.67%and 86.67%,and the highest in the stem both were 40%in the jointing stage;The richness of endophytic fungi was higher in the overwintering stage and mature stage of stem,and higher in the tillering stage and mature stage in the root.There were differences in the diversity of endophytic fungi in different growth stages,and the diversity index was the highest in the mature stages,and the richness of root flora in wheat was higher than that in stem during the same growth period.In this study,a selective medium for isolation and detection of pathogens under non-sterile conditions and wheat field soil was developed,and the diversity of endophytic fungi in wheat roots and stems was systematically analyzed,then preliminarily understood that the number,species and distribution of endophytic fungi in wheat roots and stems were affected by geographical location,growth period and so on,and provided basis for further research on the diversity of endophytic fungi in wheat,and also laid a theoretical foundation the application of endophytic fungi in agricultural production in wheat. |
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