| The seasonal dynamics of airborne conidia concentration of Blumeria graminis f.sp.tritici were monitored on different varieties at two sites in 2019 and 2020 growing seasons,using by pathogen spore trap technique.Different sets of models were established based on microscope or Real-time PCR assay in wheat powdery mildew estimation,and the models were compared.Our research of the Long-distance spore transmission path of wheat powdery mildew pathogen was studied to take advantage of HYSPLIT-4 model and combined with meteorological data.In particular,it is necessary to define the source of pathogen in the plain of China.These studies explored the mechanism of spore dispersion of wheat powdery mildew at different scales(in the field or between regions).The main conclusions obtained include:The dynamics of airborne conidia concentration of powdery mildew were almost show that the conidia concentration of Blumeria graminis f.sp.tritici gradually increased with the development of the index of disease and appeared several obvious peaks.Finally,the conidia concentration decreased in the late milk stage.Among them,the maximum of airborne conidia concentration appeared at the early late milk stage on ‘Jingshuang16’ in 2019 growing seasons at Langfang and ‘Bainong207’ in 2020 growing seasons at Yuanyang,it appeared in the heading stage on ‘Jingshuang16’ and ‘Shi4185’ and in the flowing stage on ‘Baofeng104’ in 2020 growing seasons at Langfang.The results of time series analysis of powdery mildew in two sites and different varieties in 2019 and 2020 growing seasons were different.It showed that Langfang ‘Jingshuang 16’ in 2019 growing season’s data can be fitted with ARIMA(2,0,2)model,Langfang ‘Jingshuang 16’ in 2020 growing season’s data conformed to the ARIMA(1,1,0)model,‘Shi 4185’ and ‘Baofeng 104’ in 2020 growing season’s data conformed to the ARIMA(2,1,2)model and ARIMA(0,1,1)model,respectively,and Yuanyang ‘Bainong 207’ in 2020 growing season’s data conformed to the ARIMA(0,0,1)model.The analysis results of correlation showed that,the conidia concentration of Blumeria graminis f.sp.tritici on three varieties in Langfang in 2020 growing seasons had significant or very significant positive correlation with relative humidity,and most of which had significant or very significant negative correlation with wind speed and solar radiation.The conidia concentration had significant positive correlation with temperature on different varieties in 2019 and 2020 growing seasons at Langfang and Yuanyang.There were significant linear and logarithmic relationships between cumulative conidia concentration before the day of disease measuring or before the current week of disease measuring and disease index.According to the results of correlation,the sets of models were derived by meteorological parameters only,by inoculum only,and both by meteorological parameters and inoculum to the index of disease.The model derived by inoculum only considers the concentration of pathogen which is more suitable for the estimation of wheat powdery mildew.However,the models based on inoculum only showed some differences on different varieties in two growing seasons at Langfang and Yuanyang.There was significant difference on ‘Jingshuang 16’ in two growing seasons,but there were no significant differences between most of the highly susceptible varieties at two sites in 2020 growing season,and there were significant differences between high susceptible varieties and high resistant variety.The monitoring results of conidia concentration on different varieties based on Real-time PCR spore quantitative technique had significant positive correlation with microspore counting technique.A method for monitoring the conidia concentration in the air was set based on Real-time PCR,and the estimation models of powdery mildew was established.The results of forward air parcel trajectories during the epidemic period in autumn at the pathogen oversummering region showed that,the air parcel in Yunxi and Yunyang from Hubei was mainly transported to the mountainous areas of northwest Hubei,the air parcel in Linzhou from Henan is mainly transported to the south of Hebei and the east of Henan,and the air parcel in the Lingbao from Henan is mainly transported to the low mountainous areas in the southeast and the south of Shaanxi.The air parcels in Linwei,Meixian,Huxian,Changwu,Longxian from Shanxi were mainly transported to the west of Guanzhong area and eastern region of Gansu province.The results of forward air parcel trajectories during the epidemic period in spring at the pathogen region showed that,the representative points were selected to simulate the forward air parcel trajectories of pathogen sources in Yunxi from Hubei,Linzhou,Gongyi and Lingbao from Henan,Meixian,Longxian and Linwei from Shanxi province during the epidemic period of the disease in spring,respectively: 1)During this period the low-altitude air parcels in Yunxi from Hubei were mainly transported to the northwest mountainous areas of Hubei and southern Shanxi.The middle-altitude air parcels were mainly transported to the east of Guanzhong Plain,northwest of Hubei and southwest of Henan.And the high-altitude air parcels were mainly transported to the east of Guanzhong in Shanxi Province,Nanyang in Henan province and the wheat region of Hubei Jianghan Plain,respectively.2)The low-altitude air parcels in Linzhou,Gongyi and Lingbao from Henan in spring were mainly transported to the northward of Henan,the air parcels in Linzhou of Henan were transported to the north of Henan and south of Hebei,the air parcels in Gongyi of Henan were transported to the central and northern part of Henan,and the air parcels in Lingbao of Henan were transported to the west of Henan and the east of Guanzhong of Shanxi province.The middle-altitude air parcels in Linzhou of Henan were mainly transported to the north of Henan,the south of Hebei and the west of Shandong,the air parcels in Gongyi of Henan were mainly transported to the north of Henan,Hebei,the south of Shandong and the southwest of Henan,and the air parcels in Lingbao of Henan were mainly transported to the southwest of Henan.The high-altitude air parcels were mainly transported to the southeast of the selected points of Henan.The air parcels passed through most of the plain of wheat of Henan province and can also transported to Hebei,Shandong,Anhui,Jiangsu and other places.3)The low-altitude air parcels in Longxian,Meixian and Linwei fom Shanxi province in spring almost transported to the north or west of the selected points,the air parcles in Longxian and Meixian of Shanxi were mainly transported to the west of Shanxi and the east of Gansu province,and the air parcles in Linwei of Shanxi were transported to the middle of Guanzhong Plain and Weibei area.The path of middle-altitude air parcles in spring were more complex.The air parcles in Meixian were mainly transported to south of Shanxi,Weibei,the centre of Guanzhong Plain and the east of Gansu province.The air parcles in Longxian were mainly transported to the east of Gansu,the air parcles in Linwei were mainly transported to Weibei area,the south of Shanxi,the east of Guanzhong Plain and the south of Henan province.The high-altitude air parcles generally transported to the east of selected points,they passed through most of the plain of wheat of Shanxi province and can be transported to part of the plain of wheat of Hubei and Henan province.The results of backward air parcel trajectories of the area which pathogen cannot oversummer showed that,the low-altitude air parcles in Donghai of Jiangsu Province during spring mainly comes from Shandong and Anhui.The middle-altitude are mainly from Henan and Shandong.The high altitude is mainly from Shandong,Henan and Anhui.1)The low-altitude air parcles in Donghai of Jiangsu was main from Shandong and Anhui province.While the middle-altitude air parcles mostly came from Henan and Shandong province.There were more air parcles from Shandong,Henan and Anhui provinces by high-altitude.2)During the epidemic period of the disease in spring,the low-altitude air parcles in Pinghu of Zhejiang were mainly transported from Zhejiang province itself.The middle-altitude air parcles were mainly came from Anhui and Jiangsu province.And the high-altitude air parcles came from Anhui province.According to the analysis results of the air parcel trajectories during the epidemic period of the disease in autumn and spring: in addition to the local sources,our modeling results suggest that there is a high probability of significant spore exchanges among wheat-production regions in Shanxi and Hubei province.While,in addition to local dispersion,the inoculum from Henan province would be transported mainly into Hebei porvince,and the inoculum sources of Henan may also provide spores to the plain of wheat-production regions of Shandong,Anhui,Jiangsu and Hubei province.The results of air parcel trajectories were generally consistent with the results of interval relationship of genetic diversity of wheat powdery mildew population. |
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