In order to clarify the pathogen composition and pathogenicity of wheat crown rot in different ecological regions of Gansu province, more than 40 samples with typical symptoms of wheat crown rot were collected from 22 sampling sites in 11 counties and districts, including Longnan Huicheng Basin, Longdong Dry Plateau and Hexi Irrigation District in Gansu Province from grain filling to milk ripening stage. The pathogens were isolated and purified by tissue separation method. The pathogens were identified by morphological and molecular biology, and the pathogenicity of representative strains were determined by inoculation. The results showed that 76 isolates of Fusarium were screened from 104 cultures by Fusarium specific primers, and identified by morphology and TEF sequences analysis. There were 48 isolates of Fusarium pseudograminearum (63.2%), 10 isolates of F. graminearum (13.2%), 8 isolates of F. sinensis (10.5%), 6 isolates of F. equiseti (7.9%), and 4 isolates of F. acuminatum (5.2%). The pathogenicity of these isolates were significantly different, among which, that of F. pseudograminarum was the strongest, with an average disease index of 84.37; F. graminearum was the second with an average disease index of 67.06; the mean disease index of F. equiseti and F. sinensis were 66.83 and 33.97, respectively. The pathogenicity of F. acuminatum was the weakest, with an average disease index of 17.83. Combined with the isolation frequency and pathogenicity, five pathogens were identified to cause wheat crown rot in Gansu province, among which the dominant pathogen is F. pseudograminearum.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |