Stem rusts on wheat, barley, and oat in Canada in 1996 and 1997

In 1996, stem rusts of wheat and barley [Puccinia graminis f. sp. tritici] and oat [P. graminis f. sp. avenae] were light in eastern Canada, and in we stern Canada they were confined mainly to the Red River Valley of Manitoba, where maximum severities of 40% occurred in lines of susceptible wheat in nurseries. Tn 1997 only traces of stem rust were found on any host at any l ocation. There were no infections in commercial wheat fields in 1996 or 199 7. Only trace levels of stem rust were found in cultivated barley both year s. There was no stem rust in commercial oat fields in 1996 or 1997. Infecti ons in wild oat did not exceed 15% in either year and occurred only in Mani toba. In 1997, most isolates collected from cultivated or wild barley, and about one-half of those collected from wheat, were rye stem rust [P. gramin is f. sp. secalis]. Pathotype identification was made on only 14 collection s obtained from wheat, and on 19 from wild or cultivated barley in Manitoba in 1997. During both years, 24 pathotypes of P. g. tritici were identified in collections from all sources. TPMKR was the most common in 1996 and 199 7 on wheat and cultivated or wild barley in Manitoba and Ontario. From coll ections obtained from British Columbia in 1997, QFCSR and RCCJN were the mo st common. In 1996 QCCJD was common on cultivated and wild barley in Manito ba, but was not detected in 1997. A similar pathotype (QCCJN), however, was commonly found in 1997. All four isolates obtained from cultivated barley in British Columbia were QCCJN. All isolates of P. g. tritici collected fro m wheat in Canada and from cultivated and wild barley in Manitoba were viru lent to the individual genes Sr5, Sr21, Sr9g, and Sr9d. All isolates were a virulent to genes Sr22, Sr24, Sr25, Sr26, Sr27, Sr29, Sr30, Sr31, Sr32, Sr3 3, Sr35, Sr37, and Sr40; to a series of resistant lines (Mida-McMurachy-Exc hange, Frontana-K58-Newthatch, CI8154/(2)Frocor, Alpha 16, BW197, RL6076, R L6088, RL6172); to the bread wheat cultivars Kenya Farmer, Agatha, Glenlea, Katepwa, Leader, Roblin, AC Taber, Grandin, and AC Domain; and to the duru m cultivars Plenty, AC Melita, and Sceptre. From collections of P. g. avena e in Manitoba, NA29 was the most common in 1996 and 1997. Other pathotypes were NA18, NA27, NA28. NA30, and NA68. Only three collections were obtained from Ontario each year. In 1996 two were NA26 and one was NA32, and in 199 7 all were NA25.