福建省玉米小斑病菌侵染不同细胞质玉米品种的病斑型及其致病型群体结构分析

目的]为了解福建省玉米小斑病菌的致病性及其群体结构,方法]研究了2014-2015年采自福建省7个地区的247个菌株侵染不同细胞质玉米品种C103T、C103C、C103S和C103后叶片的病斑型,结果]结果表明,所有供试菌株均可引起4个玉米品种发病,其病斑长度平均值分别介于1.15 mm-5.40 mm、1.06 mm-4.70 mm、1.09 mm-4.84 mm和1.15 mm-5.21 mm之间。根据病斑长度将病斑分为I和II型,其菌株出现频率分别为80.26%和19.74%。依据各菌株依次在4个不同品种玉米上的病斑型,供试菌株群体被划分出15个致病型,其中致病型CHP15(病斑反应型I-I-I-I)为优势型,致病型CHP11(病斑反应型II-I-I-I)为亚优势型,优势型和亚优势型分别占供试总菌株数的57.49%和9.72%。结论]不同地区菌株之间的致病型组成及其出现频率存在多样性。此外,其中的235个O小种菌株也出现了14个致病型,菌株间的致病力存在明显的分化。

Pathotype and Its Population Structure of Cochliobolus heterostrophus in Fujian Province

To know the pathotype and population structure of Cochliobolus heterostrophus in Fujian Province, 247 C. heterostrophus isolates, collected from seven regions in Fujian Province during 2014-2015, were used to study the lesion types of leaves of‘C103T’,‘C103C’,‘C103S’and‘C103’with different cytoplasm, using the method of measuring lesion length. The results showed that all the tested isolates could cause disease incidence in four corn varieties, with the average value of lesion length as 1.15-5.40 mm, 1.06-4.70 mm, 1.09- 4.84 mm and 1.15-5.21 mm, respectively. According to their length, the lesions were divided into I and II type, and the frequency of the tested isolates in the two lesion types was 80.26% and 19.74%, respectively. Base on the lesion type of each isolate on the four corn varieties in order, the tested isolates were divided into 15 pathotypes, the pathotype of CHP15 (lesion type of“I-I-I-I”) and CHP11 (lesion type of“II-I-I-I”) was dominant type and sub-dominant type, respectively. The percentage of dominant and sub-dominant type was 57.49% and 9.72%, respectively. The composition of pathotypes and frequencies of the tested isolates from different locations exhibited abundant diversity. In addition, among the 235 isolates from O races, 14 pathotypes were observed. There was significant pathogenicity differentiation among these isolates.