摘要：水稻褐变穗病是黑龙江省水稻生产中主要稳部病害.利用形态学、分子生物学及致病性测定等方法确定黑龙江省水稻褐变穗病害病原种类.对采自黑龙江省14个市县水稻产区的水稻褐变稳病病样作单孢分离,共获得119个菌株.根据菌落与分生孢子形态特征,归类后获得3类菌株,主要为链格孢属(Alternaria sp.),共112株,其次为镰孢菌属(Fusarium sp.),共5株,再次为青霉菌(Penicillium sp.),共2株.选取不同地区3种具有代表性20个链格孢属(Alternaria sp.)菌株,5个镰孢菌属(Fusarium sp.)菌株,2个青霉菌(Penicillium sp.)菌株作致病力测定,其中20个链格孢属菌株均导致水稻发病,而镰孢菌属和青霉菌属菌株均未致病.对112个链格孢属菌株作形态学鉴定,并测定其代表性菌株ITS序列,确定水稻褐变穗病病原为链格孢(Alternaria alternata (Fr.)Keissl).经生物学特性研究,该病原菌最适培养基为大米马铃薯煎汁培养基,菌丝生长最适温度为27℃,最适宜pH为6.5,最适光照条件为24h黑暗,病原菌孢子最适萌发温度为30℃,pH为7,光照条件为24h黑暗,最适碳源为果糖和蔗糖,最适氮源为胰蛋白胨和牛内膏.%Rice brown panicle disease was a main rice panicle disease in Heilongjiang Province.In order to indentify the pathogen which caused rice brown panicle disease,morphological identification,molecular identification and pathogenicity test had been done,which would be beneficial for theeffective control of rice brown panicle disease.A total of 119 strains were obtained from the single spore isolation of rice sprouts from 14 counties in Heilongjiang Province.According to the colony morphological characteristics and conidial morphology of the strains in PDA plates,mainly for Altemaria (Alternaria sp.),there were a total of 112 strains,followed by five strains of Fusarium sp.(Fusarium sp.),two strains of Penicillium (Penicillium sp.).Representative strains of 20 Alternaria alternata,five Fusarium strains and two Penicillium strains from different regions were selected for pathogenicity determination.Among them,20 strains of Alternaria alternata were able to infect rice and cause typical symptom;however,Fusarium and Penicillium strains did not cause the incidence of rice.Morphological identification of 112 strains of Altemaria altemata was carried out and the representative strain ITS sequences were determined,finally determined the pathogen which caused the rice brown panicle disease was Alternaria alternata (Fr.) Keissl.At the same time,the biological characteristics of the pathogen were studied.The optimum culture medium was rice patato juice culture medium,the most suitable temperature for mycelial growth was 27 ℃,the optimum pH was 6.5,and the most suitable light condition was 24 h in darkness,the most suitable germination temperature of pathogenic spores was 30 ℃,pH 7,light condition for 24 h in darkness,the optimum carbon sources were fructose and sucrose,the optimum nitrogen sources were tryptone and beef extract.