甘薯根腐病病原分子鉴定及防治药剂筛选

Molecular Detection of Sweetpotato Root Rot Disease and Screening of Fungicides

通过组织分离法对江苏徐州市的甘薯根腐病进行了病原菌分离纯化,两年共获得了30株病原菌;经PCR扩增,获得了4个致病菌rDNA-ITS片段,序列大小为535~568bp,核苷酸一致率为88%~100%;结合形态学观察和rDNA-ITS序列测定结果,将这4株致病菌鉴定为尖孢镰孢菌和茄病镰孢菌。利用菌丝生长速率法测定了8种杀菌剂对甘薯根腐病菌的室内抑制效果,研究结果表明,咪鲜胺锰盐和枯草芽孢杆菌的室内抑制效果居前2位,1μg/mL的抑制率分别达到74.70%和72.26%,其EC50分别为0.0095μg/mL和0.0001μg/mL。田间药效试验结果表明:在栽种40d时,咪鲜胺锰盐对甘薯根腐病的防治效果最好;在收获时,枯草芽孢杆菌的防效最好。

The pathogen species of sweetpotato root rot were isolated and purified by tissue isolation in Xuzhou City,Jiangsu Province.Thirty isolates were obtained in two years.By using PCR,the fragment size of rDNA internal transcribed space(rDNA-ITS)in four pathogenic strains was 535~568 bp,and the nucleotide concordance rate was 88%~100%.They were identified as Fusarium oxysporum and F.solani by morphological observation and rDNA-ITS sequence.The inhibitory activity in vitro of 8 fungicides to F.oxysporum was determined by the mycelial growth inhibition rate.Indoor toxicity determination indicated that Prochloraz manganese and Bacillus subtilis were the top two.At the level of 1μg/mL,the inhibition rate was 74.70%and 72.26%respectively,and the EC 50 of Prochloraz manganese was 0.0095μg/mL and 0.0001μg/mL respectively.In the field,the control effect of Prochloraz manganese with the lowest disease index was the best on the 40 days after planting,while the control effect of Bacillus subtilis was the best at harvest time.