广东辣椒疫霉菌分离鉴定及其致病力和生理小种分化研究

Isolation and Identification of Phytophthora capsici in Guangdong Province and Measurement of Their Pathogenicity and Physiological Race Differentiation

分离鉴定了来源于广东省不同辣椒产区的5个病原菌分离物，经形态特征鉴定及回接发病特征观察，确定这些菌株均为辣椒疫霉菌Phytophthora capsici Leonian．广东5个菌株在cA培养基上诱导产生的孢子囊形态类似，孢子囊形状多为卵圆形或长椭圆形，乳突明显，孢子囊平均大小40．8-45．9μm（l）×23．2—30．9μm（6），l/b1．4—1．8．菌株间菌丝生长速率、产孢能力及致病力有明显差异，经生理小种鉴别，4个为Race3，1个为Race1，初步推定Race3为广东辣椒疫病病原菌的优势小种．

Five isolates collected from different pepper-cultivating regions in Guangdong Province were determined. Based on their morphological characteristics and symptoms after re-inoculated to pepper, these isolates were identified as Phytophthora capsici Leonian. The sporangia induced on CA medium were morphologically similar and most of their shape were ovate or elliptic, with obvious papillate. The mean size of the sporangium was 40.8-45.9 μ m（l）× 23.2-30. 9 μm（ b）, with lib ratio 1.4-1.8. There were evident differences in mycelial growth rate, productivity of sporangia and pathogenicity to pepper among the isolates. Race 3. Physiological characters test showed that one isolate belonged to Race 1, 4 isolates belonged to Race 3 is probably the superior race in Guangdong Province.