甘肃藜麦霜霉病调查及其病原菌鉴定

霜霉病是严重危害藜麦的世界性病害。为了明确甘肃藜麦霜霉病的发生与危害情况，以及病原菌的种类及致病力分化情况，对藜麦霜霉病进行了系统调查，基于形态学和分子生物学方法对病原菌种类进行鉴定，并采用叶盘法在室内人工接菌测定致病力。病害调查结果表明，甘肃不同生态区藜麦霜霉病发生普遍严重，局部地区呈爆发态势；发病率和病情指数在临夏二阴气候区最高，分别为83.70%和80.44，白银干旱区最低，分别为19.26%和16.67。结合形态学和分子生物学鉴定结果，甘肃藜麦霜霉病病原菌被确定为Peronospora variabilis，不同菌株孢子囊和卵孢子大小存在显著差异（P<0.05）。致病力分析结果表明，不同菌株之间存在显著差异（P<0.05），致病力最强的是来自临夏二阴气候区的菌株GSKL，最弱的是来自天祝高寒区的菌株GSTZ，病情指数分别为90.00和44.67。系统发育分析结果发现，甘肃不同生态区霜霉病菌株之间存在地理种群遗传分化。本研究为甘肃藜麦霜霉病的防控奠定了理论基础。

Diseases Investigation and Pathogen Identification of Quinoa Downy Mildew in Gansu Province

Downy mildew（DM）is an extremely damaging disease for quinoa worldwide. In order to clarify the disease occurrence and damage， pathogenicity differentiation and pathogen species of quinoa DM， the disease was systematically investigated， the pathogen species were identified based on morphological and molecular biological methods， and the pathogenicity was determined by artificial inoculation in the laboratory using leaf disc method. The results of disease investigation showed that the quinoa DM in different ecological regions of Gansu was generally serious， and even in outbreak trends in some areas. The incidence and index of DM disease in Linxai Eryin climate region were 83.70% and 80.44， respectively， and the lowest were 19.26% and 16.67 in Baiyin semi-arid region， respectively. The pathogens of quinoa DM in Gansu province were identified as peronospora variabilis with morphological and molecular biological methods， and there were significant differences in the size of sporangia and oospores among different strains（P<0.05）. Pathogenicity analysis showed that there were significant differences among different strains（P<0.05）. The most virulent strain was GSKL from Linxai Eryin climate region， and the weakest strain was GSTZ from Tianzhu high-elevation cold region with disease index of 90.00 and 44.67， respectively. Phylogeny analysis showed that DM strains among different ecological regions of Gansu existed genetic differentiation of geographic populations. This study provides a theoretical foundation for the prevention and control of quinoa DM in Gansu province.