应用real-time PCR评价三种杀菌剂对小麦条锈病的防治效果

为更加精确有效地评估杀菌剂对小麦条锈病的防效,本研究利用real-time PCR检测潜育阶段的分子病情指数(molecular disease index,M DI)并结合田间病情分析,对三种杀菌剂的防效进行评价。春季返青后在品种铭贤169和京0045试验小区的诱发中心接种小麦条锈菌夏孢子,待充分发病后将其铲除。设置播种前2%立克秀拌种,接种后21和28 d分别喷施25%阿米西达和30%苯甲-丙环唑1 500倍液三种处理。发病后调查不同处理的普遍率和严重度,计算病情指数和AUDPC。结果表明,阿米西达和苯甲-丙环唑对小麦条锈病具有良好的防效且能够明显抑制发病中心的扩展,而经立克秀拌种对该病害的防治效果和发病中心扩展的抑制作用均不理想。对京0045于发病中心接种后24和33 d采样,经双重real-time PCR定量检测,计算MDI。结果显示潜育检测获得的M DI与AUDPC之间均具有极显著的相关性;阿米西达和苯甲-丙环唑对潜育期小麦条锈菌的扩展具有明显的持续抑制作用,而立克秀拌种仅对小麦条锈菌潜伏初期的扩展表现出一定的抑制作用。

Efficacy evaluation of three kinds of fungicides on wheat stripe rust using real-time PCR

For earlier and more accurate assessment efficacy of three kinds of fungicides on wheat stripe rust, the molecular disease index (MDI) of latent period obtained by real-time PCR and field actual disease were analyzed in this study. The induction centers among wheat cultivars Mingxian 169 and Jing 0045 experimental plots were inoculated with urediniospore of Puccinia striiformis f. sp. tritici (Pst) during the returning green-jointing stage and eradicated when these plants showed disease fully. Seed treatment with 2% Tebuconazole was conducted before sowed. 25% Azoxystrobin and 30% difenoconazole propiconazole were sprayed at 21 and 28 d after inoculation, respectively. Disease incidence and severity of different treatments were assessed, and disease index (DI), area under disease development curve (AUDPC) were calculated. The results revealed that plots treated with azoxystrobin and difenoconazole·propiconazole showed light symptoms of wheat stripe rust and disease development was restricted within certain ranges, while Tebuconazole treated plots showed severe symptoms with larger ranges. Samples of wheat cultivar Jing 0045 were collected at 24 and 33 d after the induction centers inoculation, respectively. Duplex real-time PCR was applied to quantify and MDI was obtained. The results indicated that the regressions between MDI and AUDPC were significant; Azoxystrobin and difenoconazole propiconazole had continued inhibition effect to Pst in latent period, while seed treatment of Tebuconazole showed inhibition effect just at the beginning of latent period.