中国马铃薯晚疫病的研究进展和建议

轻微感染的种薯可以越冬，第二年播种后产生病苗，形成中心病株，再向周围蔓延，形成发病中心；1996年中国首次报道发生A2交配型，以后在马铃薯主产区陆续发现A2交配型，其发生频率北方高于南方；对人工培养基上卵孢子产生的条件，病菌的薯片培养法和液态氮的保存效果，也进行了初步研究；影响晚疫病开始流行的气候条件主要是温度和湿度，但是在我国复杂的地理气象条件下，温、湿度在各地的作用是不同的，在春旱地区，湿度是限制因素，在潮湿多雨的地区，湿度是限制因素；经过多年的试验，初步建立了宁夏南部山区马铃薯晚疫病流行的灰色预测模型，可以对当地晚疫病的流行进行长期预测，回测准确；抗病育种的研究，目前倾向于水平抗性的筛选，已评价出一批对晚疫病具有水平抗性的优良无性系，利用这些无性系，有希望培育出具有水平抗性的有推广价值的高产品种；对马铃薯块茎晚疫病鉴定方法，马铃薯抗晚疫病的遗传工程也开展了研究，并取得良好进展；室内菌株测定和田间试验，均证明抗瑞毒霉菌株的存在，导致瑞毒霉防效降低，但是它的复配药剂瑞毒霉锰锌仍保持很高的防效；中国在近几年已研究出一种新的杀菌剂氟吗啉，具有很好的保护和治疗效果，明显高于克露、普力克、瑞毒霉以下问题的研究和调查：消灭或控制带病种薯内病菌的方法；卵孢子在流行中的作用；消灭土壤内或残株内部孢子的方法；开展晚疫病菌对农药抗性的监测；加强长、短期测报技术的研究，成立全国或地区晚疫病测报中心；春秋二作区，不同地区的温室和网室网疫病发生的特点；品种抗病性的监测。

Progress and suggestion on potato late blight research in China

The survey throughout major potato production regions indicated that A2 had been present in all provinces with various frequencies. Late blight breaks out usually most seriously where the weather is consistently cool and rainy. Under the conditions of diversified geographic and meteorological across China, the temperature and moisture may have different effect in various places. The preliminary-established gray Potato Late Blight-forecasting model for southern mountain regions of Ningxia could be used as a routine predication for late blight. Some clones with horizontal resistance have been screened out after being evaluated for a few years. In Hebei and Inner Mongolia, some major cultivars in production contain horizontal resistance to late blight. Recent year's genetic engineering on potato late blight was also conducted in China. Tests in both lab and fields indicated that metalaxyl resistant isolates appeared and the effectiveness of metalaxyl on late blight disease were weakened. However, the Ridomil MZ 58 WP still hold high control effect. A new fungicide named Flumborph was synthesized in recent years in China. It shows very good systemic and protective control effect on late blight. A significant progress has been made on using ferment liquid from Xenorhabdus nematophilus in both lab antagonize test and greenhouse field control trials. Some suggestions presented in the workshop are related to research aspects below: eradication of pathogen in diseased tubers and oospores in the soil; monitoring the chemical resistant isolates; short-term disease forecast; disease epidemic pattern in double-cropping region; formation of a national or regional late blight forecast center.