Rice blast disease is the major disease in rainfed lowland area of Thailand. The causal fungus of this disease is Pyricularia grisea Sacc. Variation of this fungus was higher than other rice pathogens. This report used near isogenic lines (NILs) to detect the variation, pathothype and virulence spectrum of the fungus in Thailand during 2002 - 2005. Trap blast nurseries consisted of 9 Thai local cultivars and 18 NILs were conducted at Ubon Ratchathani Rice Research Center, Khon Kaen Rice Research Center, Phrae Rice Research Center, Phitsanulok Rice Research Center, and Phatthalung Rice Research Center. Single conidia was isolated from infected rice leaves. Virulence spectrum of blast populations were screened on 18 NILs. Two thousand four hundred seventy... |