![Sample our Environment & Agriculture journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5934/TOC-Subject-Sample-2021-Environment-Agriculture.jpg"})
Abstract
Crown rust (Puccinia coronata f. sp. avenae) of oat (Avena sativa) was severe in Manitoba in 1996 and 1998 but was relatively mild in 1997. Heavy crown rust infections were also commonly found on wild oat (Avena fatua) in eastern Saskatchewan in 1996 and 1998. Warm weather with frequent dew periods favoured spread of the disease across southern Manitoba in 1996 and 1998. By early to mid-August, moderate to heavy infections (40-90%) were commonly found in fields of susceptible cultivars, such as Robert, Riel, Dumont, AC Preakness, and Jerry. Only trace levels of infections were found on the resistant cultivars AC Assiniboia, AC Medallion, and Triple Crown. From the eastern prairie region (Manitoba and eastern Saskatchewan), 142, 123, and 111 virulence phenotypes were identified, respectively, from 328, 255, and 265 isolates in 1996, 1997, and 1998. From Ontario, 13, 29, and 48 virulence phenotypes were identified, respectively, from 22, 81, and 106 isolates in 1996, 1997, and 1998. Isolates with virulence to both genes Pc38 and Pc39 predominated in Canada during the years from 1996 to 1998. Combined virulence to genes Pc38, Pc39, and Pc68 was found in several isolates from Manitoba in 1998. Virulence to genes Pc48 and Pc96 ranged from 1.8 to 5.8% and virulence to gene Pc68 remained below 1.9% in the eastern prairie region during the years from 1996 to 1998. Virulence to genes Pc58 and Pc59 occurred at low levels in Ontario. Virulence to gene Pc94 was detected for the first time in the prairie region in 1998. Various combinations of genes Pc48, Pc58, Pc59, Pc68, Pc94, and Pc96 would be useful for combining resistance against crown rust in Canada.
