寄生玉米的6种腐霉及其致病性研究

 从国内12省、自治区、直辖市玉米植株上分离出腐霉菌菌株,依据形态特征、培养性状、生长抑制温度,以及产生的有性与无性器官,鉴别出6个腐霉种:棘腐霉(Pythium acanthicum Drechsler),瓜果腐霉(P.aphanidermatum(Edson)Fitzpatrick),强雄腐霉(P. arrhenomanes Drechsler),禾生腐霉(P.graminicola Subramaniam),肿囊腐霉(P.inflatum Matthews),寡雄腐霉(P.oligandrum Drechsler),其中肿囊腐霉出现频率高,分布广泛。回接玉米表明,腐霉能够侵染玉米并引起病害,肿囊腐霉、禾生腐霉、强雄腐霉、棘腐霉是玉米青枯病的重要致病菌;瓜果腐霉能够引起玉米中部茎节腐烂;寡雄腐霉虽寄生玉米,但对玉米成株无致病力。

IDENTIFICATION AND PATHOGENICITY OF PYTHIUM SPP. ISOLATED FROM MAIZE

Some strains of Pythium isolated from maize were studied on morphological characteristics and pathogenicity on maize. Based on morphology, cultural characters and temperature responses, 6 species of Pythium were identified:P. acanthicum Drechsler ,P. aphani-dermatum (Edson) Fitzpatrick, P. arrhenomanes Drechsler, P. graminicola Subramaniam, P. inflatum Matthews and P. oligandrum Drechsler. Frequency of isolation of P. inflatum was 60. 6%, and it was extensively distributed in China. The result of the pathogenicity test showed that Pythium can parasitize and cause diseases on maize. The species P. inflatum, P. graminicola, P. arrhenomanes and P. acanthicum are pathogens that cause basal stalk rot on maize; P. aphaniderrnatum causes maize stalk rot; P. oligandrum although can parasitize maize yet is avirulent in adult plants.