Study On Vegetative Compatibility Of Poplar-Canker's Pathogen

Our country have recorded 17 kinds of pathogen of poplar-canker: Cytospora chrysosperma (Pers.) Fr. ; Dothichiza populea Sacc. et Briard.) Phomopsis populina Voglino; Sphaeropsis malorum Peck; Fusicoccum leucostomum Sacc. Botryodiplodia populea.The main pathogens of poplar-canker are Botryosphaeria dothidea and Cytospora chrysosperma which distribute on most culturing poplar's areas of our country. Because poplar-canker's pathogen is various and abroad distribute and symptom is complicated. In order to know variety of pathogens of poplar-canker ,ecological geographical distribution, pathogenicity of pathogens,and cultural morphology and vegetative compatibility of Cytospora chrysosperma isolates. Isolates collected from 18 provinces and different poplars were identified , determined growth rate and pathogenicity, and cultural morphology and vegetative compatibility of Cytospora chrysosperma.The results as fallow:1. Separation and identification of isolates180 isolates were collected from 18 provinces and 36 poplar varieties,126 isolates were identified. These isolates are Dothiorella(Botryosphaeria ),Cytospora,Coniothyrium,Phomopsis,Fusarium.Result of identification indicate that pathogen of poplar-canker are variety in our country. According to the number of pathogen in different areas, Dothiorella gregaria(Botryosphaeria dothidea)mainly distribute in warm,humid areas; Cytospora chrysosperma mainly distribute in lower temperature and drought areas.2. Growth rate and pathogenicity of pathogenAccording to the average growth rate of pathogen , Cytospora grow faster than Botryosphaeria,followed by Phomopsis,Phoma,Coniothyrium grow the slowest. Classified value of Botryosphaeria and Cytospora show that pathogen exist divide phenomenon.The result of determined average pathogenicity show that pathogenicity of D.gregaria is stronger than C.chrysosperma, pathogenicity of Coniothyrium sp. is best weak.Pathogenicity of D.gregaria and C.chrysosperma are similar. Strains of C. chrysosperma came from lower temperature and drought of the northeast and northwest whose pathogenicity are strong or stranger. B.dothidea and C.chrysosperma are two main pathogens of poplar-canker which exist,but the differentiation and variations are exist overlapping and similarities of regions.