| In recent years,maize stalk rot has been aggravated year by year in Xinjiang,and now it has become an important potential factor affecting maize planting in Xinjiang,especially the collapse before mechanized harvesting.However,research on the occurrence and prevention and control technology of maize stalk rot in Xinjiang is still very weak.In this thesis,we investigate the occurrence and distribution of maize stalk rot in irrigated maize production areas in Xinjiang,isolate and identify the dominant pathogenic Fusarium,and screen and evaluate the resistant germplasm resources in order to provide reference for accurate monitoring and scientific prevention and control of maize stalk rot in irrigated maize production areas in Xinjiang oasis.The main results are as follows:1.The results of the analysis of the occurrence and damage of maize stem rot in irrigated maize production areas in Xinjiang showed that:the average disease field rate of maize stem rot in irrigated areas in Xinjiang was 77.32%,and the average disease plant rate was 39.66‰,among which the spring-sown maize production areas in northern Xinjiang（97.22%,51.86‰）were significantly heavier than the resown maize production areas in southern Xinjiang（30.00%,17.70‰）,and the disease occurrence varied in degrees in each state,specifically:Bo Prefecture（100%,78‰）,Yili Prefecture（100%,68.04‰）had the heaviest incidence,followed by Urumqi（100%,55.50‰）,Tacheng Region（93.33%,38.80‰）moderate incidence,while Changji Prefecture（92.86%,13.43‰）,Kashgar Region（30%,17.70‰）overall lighter incidence.According to the statistics of counties and cities,the damage in Xinyuan County（100%,126.2‰）was the heaviest throughout the whole territory,followed by Bole City（100%,117.14‰）,while no occurrence of maize stalk rot was found in Gashi County,Shule County and Shuhu County for the time being.Analysis of factors affecting the prevalence of maize stalk rot showed that the average rate of diseased plants in commercial lines of maize（48.12‰）was 3.09 times higher than that of seeded maize（15.56‰）.The disease rates of drip irrigation with film,drip irrigation without film,diffuse irrigation with film,and diffuse irrigation without film were 48.39‰,32.67‰,23.63‰,and 40.07‰,respectively,and there was no significant difference（P<0.05）in the disease rates of the four cultivation modes.2.The results of isolation and identification of dominant pathogens of corn stem rot showed that 335disease samples were collected for two consecutive years from 2020 to 2021,and a total of 601 isolates were obtained,including 560 strains of Fusarium,accounting for 93.18%,indicating that Fusarium is the main pathogen.F.verticillioides,F.proliferatum,F.graminearum,F.oxysporum and F.solani were the main dominant pathogens,and the total isolation frequency was 47.51%,34.00%,4.89%,4.12%and 2.62%,among which F.verticillioides and F.proliferatum were distributed in five prefectures,and the total isolation frequency was significantly higher than that of other pathogens（P<0.05）.The results of pathogenicity test in seedling stage:the pathogenicity rate of F.graminearum（86.30%）and disease index（35.33）were significantly higher than those of the other four pathogens（P<0.05）.It was the most virulent pathogen,followed by F.proliferatum（63.33%,16.00）and F.verticillioides（55.00%,11.67）.Maize stem rot in Irrigated Maize producing areas in Xinjiang is mainly caused by F.verticillioides,F.proliferatum and F.graminearum.Among them,F.verticillioides is widely distributed,has high isolation frequency and strong pathogenicity,and is the main dominant specie causing disease.3.The identification and evaluation results of maize germplasm resources against Fusarium Wilt（Fusarium Verticillium）showed that 14,16,37,15 and 18 materials with high resistance（HR）,resistance（R）,medium resistance（MR）,susceptibility（s）and high susceptibility（HS）were selected from 100 maize inbred line Germplasm resources provided by grain crop Research Institute of Xinjiang Academy of Agricultural Sciences,accounting for 14%,16%,37%,15%and 18%respectively.The correlation between stem rot and some agronomic characters was analyzed.The correlation coefficients between diseased plant rate and plant height,ear length,ear diameter and 100 grain weight were-0.333**,-0.388**,-0.283**,-0.379**,respectively,showing a very significant negative correlation,indicating that plant height,ear length and ear diameter can be used as reference indexes in disease resistance screening.The field performance of plant height,ear position,tasseling stage,silking stage and loose powder stage of 25resistant germplasm resources were further evaluated.Among them,21KBL026 was launched for 2 days,4days and 3 days respectively in tasseling stage,silking stage and loose powder stage.The average diseased plant height and ear position fluctuated（+4.78%and+8.13%）respectively compared with the control,Thus,a number of inbred lines with resistance to stem rot and stable field agronomic characters such as21KBL026 were selected. |
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