Races of Maize Downy Mildew in Thailand

Chuteemun Panichsukpatana  Peerawan Patanavipas  Petcharat Yowabutr  Preecha Saengsoda  Suwit Punsurin  Tuenchai  Boon-Long

 

Department of Agriculture, Bangkok. 10900.  Thailand.

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Abstract

During rainy season of the year 2000, 2001, and 2002; pathogenicity test of maize downy mildew has been conducted in different part of Thailand, the north in Chiangmai Field Crops Research Centre at Ploa, the Northeast in Loei Field Crops Experiment Station and the central part in Kanchanaburi Horticulture Experiment Station.  Eleven varieties of maize were evaluated for varietal reaction of downy mildew in those area. Tuxpeno, the standard susceptible check variety, show clear cut of different reaction between locations with resistant in Chaingmai but susceptible in Loei and Kanchanaburi.  Sukothai 1 variety also showed the same difference, which was resistant and moderately resistant reaction in Chiangmai but susceptible in Kanchanaburi and also susceptible and moderately susceptible in Loie province.  Those reaction can be concluded; there are two races of maize downy mildew: race 1: Chiangmai (less virulent); race 2: Loei and Kanchanaburi (more virulent).