基于田间自然诱导法的甘薯基腐病种质资源抗性鉴定与评价研究

Study on Identification and Evaluation of Resistance to Foot Rot of Sweetpotato Germplasm Resources Based on Natural Field Induction Method

甘薯基腐病是在浙江省东南沿海地区新发生的、由间座壳属病原菌侵染引起的真菌病害。为了筛选抗病种质资源和探索病害田间自然诱导抗性鉴定方法,对126份甘薯供试种质资源进行了田间抗性鉴定,并分析了甘薯生长后期的病情变化以及种质抗性对鲜薯产量损失率的影响。抗性鉴定结果表明,对照品种浙薯255表现为高抗,浙薯38表现为抗,浙薯13表现为高感。在89份新收集资源及当地主推品种中不存在高抗等级,抗等级的仅有3份,65%以上品种表现为高感。在抗病品种浙薯255的34份杂交后代中筛选出13份抗病种质,其中高抗的有6份,抗的有2份。甘薯生长后期病情发生显著变化,尤其是中抗、感病种质从120 d至135 d时病情指数跃升幅度大。135 d时整体发病植株的4级病级比例达93.8%,绝大多数发病植株最终基部完全腐烂或枯死。甘薯鲜薯产量与抗性水平呈线性相关,抗性好(高抗或抗等级)的品种鲜薯产量损失率可以控制在15%以下,而感病品种的鲜薯产量损失率超过65%,甚至绝收。总之,甘薯基腐病抗病品种资源稀少,通过抗病亲本的常规杂交可以获得抗性好的育种材料,发病率和病情指数均可以作为甘薯基腐病田间自然诱导抗性鉴定指标。

Foot rot of sweetpotato caused by Diaporthe destruens is a new disease in the southeast coast of Zhejiang province.In order to explore resistant germplasm resources and explore the method of resistance identification in natural induced field,we investigated and identified the resistance of 126 sweetpotato germplasm resources,and analyzed the changes of disease symptom in late growth period of sweetpotato and effects of resistance on yield loss rate of fresh storage root.The results of resistance identification showed that the control variety Zheshu255 was high resistant,Zheshu 38 was resistant and Zheshu 13 was high susceptible.Of which,no high resistance germplasm were identified among 89 new collected resources and local recommended varieties,only 3 accessions were resistant,and more than 65%of the varieties showed high sensitivity.13 resistant accessions were identified from the 34 progenies of resistant variety Zheshu255,including 6 high resistant and 2 resistant accessions.There were significant changes of disease symptom in the late growth period of sweet potato,especially the disease index sharply increased from the growth period of 120 d to 135 d in moderate resistant and susceptible germplasm.The disease grade of 93.8%of the total susceptible plants was 4 at the growth period of 135 d.Eventually,most of the susceptible plants rotted thoroughly at the base of stem or died.The yield loss rate of varieties with good resistance(high resistance or resistance)could be controlled below 15%,while the yield loss rate of susceptible varieties was over 65%,even no harvest.In a word,the resistant germplasm resources of foot rot disease of sweetpotato were scarce,the good resistant breeding materials could be obtained through the conventional hybrid breeding of the resistant parents,and the incidence and disease index might be used as the identification index of resistance to foot rot of sweetpotato in natural induced field.