洋槐上疫霉种的研究

STUDIES ON PHYTOPHTHORA SPECIES FROM BLACK LOCUST(ROBINIA PSEUDOACACIA L.)IN CHINA

经形态、生理和致病性等方面的研究,洋槐(Robinia pseudoacacia L.)上56个菌株鉴定为3个疫霉种:槐生疫霉(Phytophthora robinicola Lu,Xu & Fang,sp.nov.)、掘氏疫霉(P.drechsleri Tucker)和烟草疫霉(P.nicotianae Breda)。槐生疫霉是疫霉属的—个新种,也是引起洋槐疫病的主要致病种(占64.3%)。洋槐是掘氏疫霉的新寄主。洋槐上烟草疫霉系我国首次报道.性征研究表明:槐生疫霉同宗配合、A_1和 A_2菌株的比例大致相等;掘氏疫霉 A_1和 A_2交配型处于均势,但无同宗配合菌株;烟草疫霉 A_2交配型占绝对优势。

Fifty-six isolates from the diseased roots and bark of black locust(Robinia pseudoacacia L.)in Jiangsu Province of China were identified asPhytophthora robinicola Lu,Xu & Fang,sp.nov.,P.drechsleri Tucker andP.nicotianae Breda according to their morphological,physiological and pathogenic char-acters.P.robinicola is a new species of Phytophthora,which was the main causal agent ofblack locust.Black locust is a new host plant for P.drechsleri.P.nicotianae was firstfound on black locust in China.All isolates could form sexual organ when cultured singlyor in pairs with an opposite strain.The proportion of homothallic,A_1 and A_2 strains ofP.robinicola,as well as A_1 and A_2 mating types of P.drechsleri is more or less the same.As for P.nicotianae,A_2 mating type is predominnant.