小麦假黑胚病的研究

STUDIES ON FALSE-BLACK-EMBRYO DISEASE OF WHEAT

小麦假黑胚病近年在全疆普遍发生,一般发病率在1.5—20％,严重者达35％。受害病粒胚部变成黑褐色,经分离发现,主要由Alternaria造成。该菌分生孢子梗橄褐色,1—8个横隔膜,大小为25—80.5×4.5—6.1微米。分生孢子单生或串生,淡褐色至深褐色,倒棍棒形。孢身具2—8个横隔膜,0—3个纵隔膜,隔膜处缢缩,大小9—38×6—18微米,多具喙,喙不分枝,具0—4个隔膜。在人工培养下,病菌形态变化较大。在乳熟至蜡熟期接种,25℃下保湿36小时,潜育期3天。鉴定该病原真菌为Alternaria alternata(Fr.)Keissler。种子带菌与田间发病无直接相关性。药剂拌种无效。

False-black-embryo disease of wheat caused by Alternaria spp.occu-red very common in Xinjiang Province in recent years.The incidenceof the disease ranged 1.5—20%,sometimes up to 35%.The embryo ofdiseased seeds became black brown.Condiophores olive brown,1—8cross septa,25—80.5×4.5—6.1μm.Conidia light olive brown to darkbrown,with 2—8 cross walls and with 0—3 longitudinaly ones,obc-lavate with short beaks and borne in chains or single,9—38×6—18 μm.Beaks without forks,0—4 septa.The pathogen varies greatly in cul-ture and was identified as Alternaria alternata (Fr.)Keissier.Symptomsappear on plants 3 days after inoculation under 25℃ and 100% relativehumidity.It seems no relation between diseased seeds and field disease.Seed treatment with chemicals not useful for disease control.