广东省甘薯疮痂病病原菌鉴定及国内主要菜用甘薯种质抗性评价

为明确广东省甘薯疮痂病病原菌种类及当前国内主要菜用甘薯种质对疮痂病的抗性，结合形态学特征和rDNA-ITS序列分析对病原菌进行鉴定，并通过病圃诱发结合人工喷雾接种法对来自9个省区30个菜用甘薯种质进行连续2年的抗性鉴定。结果显示，共获得15株形态学特征及培养性状相似的菌株，其中代表菌株CRI-CJ的形态学特征与甘薯痂圆孢菌Elsinoe batatas基本一致，且在基于rDNA-ITS序列的系统发育树中与甘薯痂圆孢菌聚在一支，表明甘薯疮痂病病原菌为甘薯痂圆孢菌。30个菜用甘薯品种（系）中，抗性、中抗、中感和感病品种（系）分别为7、7、5和11个，占总数的23.3%、23.3%、16.7%和36.7%。其中抗性品种（系）有广菜薯11-52、广菜薯15-6、广菜薯 16-1、广菜薯16-19、广菜薯17-23、广菜薯17-9和广菜薯18-6，中抗品种（系）有EC01、广薯菜2号、广菜薯3号、广菜薯6号、广菜薯7号、广菜薯17-25和广菜薯18-3。不同地理来源的品种（系）对甘薯疮痂病的抗性水平存在差异，11个非广东省品种（系）中感病、中感和中抗品种（系）分别为8、2和 1个，占比分别为72.7%、18.2%和9.1%；19个广东省品种（系）中抗性、中抗、中感和感病品种（系）分别为7、6、3和3个，占比分别为36.8%、31.6%、15.8%和15.8%。表明30个国内生产主要菜用甘薯种质在抗性分布上以感病品种（系）最多，广东省内品种（系）以抗性和中抗品种（系）居多。

Identification of the pathogen causing sweet potato scab in Guangdong and resistance evaluation of main domestic leaf-vegetable sweet potato germplasm resources

In order to clarify the species of the pathogen causing sweet potato scab in Guangdong Province and to evaluate the resistance of main domestic leaf-vegetable sweet potato germplasms to this disease, the pathogen was identified by morphological characteristics and rDNA-ITS sequence analysis, and resistance of 30 leaf-vegetable sweet potato varieties (lines) collected from nine provinces were evaluated by disease nursery induction combined with artificial spray inoculation in 2018-2019. A total of 15 suspected pathogen isolates with similar morphological and cultural characteristics were obtained from scab samples, and the representative strain CRI-CJ that was proved as the causal agent of the scab by completing Koch''s postulate, was identified as Elsinoe batatas based on the morphological characteristics and rDNA-ITS sequence analysis. The results revealed that seven, seven, five and 11 accessions were resistant, moderately resistant, moderately susceptible, and susceptible to this disease, accounting for 23.3%, 23.3%, 16.7% and 36.7%, respectively, of the total accessions evaluated. Varieties (lines) showing resistant included Guangcaishu 11-52, Guangcaishu 15-6, Guangcaishu 16-1, Guangcaishu 16-19, Guangcaishu 17-23, Guangcaishu 17-9, Guangcaishu 18-6, and varieties (lines) showing moderately resistant included EC01, Guangshucai 2, Guangcaishu 3, Guangcaishu 6 and Guangcaishu 7, Guangcaishu 17-25 and Guangcaishu 18-3. Varieties (lines) from different geographic regions exhibited different resistance levels to sweet potato scab. Among the 11 accessions from provinces other than Guangdong, eight, two and one accessions were susceptible, moderately susceptible and moderately resistant, accounting for 72.7%, 18.2% and 9.1%, respectively. By contrast, among the 19 germplasm accessions from Guangdong Province, seven, six, three and three accessions were resistant, moderately resistant, moderately susceptible and susceptible, accounting for 36.8%, 31.6%, 15.8% and 15.8%, respectively. It indicated that among the tested 30 main domestic leaf-vegetable sweet potato germplasm accessions, the majorities were susceptible while varieties (lines) from Guangdong Province were mainly resistant and moderately resistant.