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Stem rust is a major disease on barley, oat, and wheat crops worldwide. The primary means of control is by host resistance genes that are incorporated into commercial varieties and have been effective against most races of Puccinia graminis Pers., the causal pathogen. Since this pathogen continually mutates, analyzing the population virulence structure is crucial to detect new races with increased virulence. Stem rust samples were collected from 2015 to 2019 from the Canadian provinces of Manitoba, Ontario, Quebec, and Saskatchewan to find the prevalence of stem rust in barley (Hordeum vulgare L.), oat (Avena sativa L.), and wheat (Triticum aestivum L.) fields and the virulence dynamics in the two pathogen populations. Stem rust was absent in cultivated wheat and at trace (<1%) levels of incidence in barley and oat fields in all years. While the dominant races of P. graminis f. sp. tritici were MCCDC (54.5%) and TPMKC (27.3%) in 2015, and TMRTF (29.2%) in 2016, race QFCSC was dominant in 2017 (52.0%), 2018 (88.4%), and 2019 (81.3%). The dominant race of P. graminis f. sp. avenae was TJS from 2015 to 2018. Race TJS declined in frequency across the years, from 89.5% (2015) to 73.7% (2016), 42.6% (2017), 49.1% (2018), and only 14.3% in 2019. The dominant races in 2019 were SGB (51.7%) and TGN (19.6%). One new race (TJQ) of P. graminis f. sp. avenae was detected in 2016 at one location near Emerson, Manitoba, which may have arisen from a single-step mutation to avirulence to Pg15 from race TJS. [ABSTRACT FROM AUTHOR]

Stem rust, caused by Puccinia graminis, is a catastrophic disease that has and continues to cause yield losses in barley, oat, and wheat crops worldwide. Use of host resistance genes is the most economic, efficient, and environmentally best method to control the disease. Resistance genes have been incorporated into most commercial cultivars and have been effective, for races in the North American populations of P. graminis. However, new races of stem rust are constantly emerging and therefore it is imperative to monitor the virulence structure in the populations to detect new races with increased virulence. Stem rust samples were collected in 2013 and 2014 in Manitoba, Ontario, Quebec, and Saskatchewan to determine the incidence and severity of stem rust in barley (Hordeum vulgare), oat (Avena sativa), and wheat (Triticum aestivum) fields and to characterize the virulence dynamics in the pathogen populations. No stem rust was found in cultivated wheat, and incidence was at trace (<1%) levels in barley fields and very low (0–5%) levels in oat fields in 2013 and 2014. In wheat trap plots and collections from barley, race QFCSC of P. graminis f. sp. tritici was dominant in 2013 (85.9%) and was the only race found in 2014. Races MCCFC, QTHJF, RFCSC, RKQSC, and TMRTF were at low (<5%) levels in 2013. From collections in oat fields and stands of wild barley, nine races of P. graminis f. sp. avenae were found in 2013, with TJS (56.9%) and TJJ (23.5%) the most frequent. In 2014, we found only six races and TJS (74.5%) and TJJ (19.1%) were the most frequent. No new races of stem rust were detected in Canada in 2013 or 2014. [ABSTRACT FROM AUTHOR]

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The article discusses a study that assessed potential impacts of climate change on biofuel wheat production in southern Saskatchewan using the Decision Support System for Agrotechnology Transfer-Cropping System Model (DSSAT-CSM). The model simulated biomass and grain yield under three climate change scenarios in the 2050s. DSSAT-CSM predicted increases in biomass and grain yield but model modification is needed to improve the prediction of climate change impacts on biofuel wheat production.

Stem rust, caused by Puccinia graminis, is a disease of cereal crops worldwide. In Canada, it is primarily controlled using resistant cultivars. Tracking the virulence structure in the pathogen populations is essential to detect new virulent races that may occur. Surveys of barley (Hordeum vulgare), oat (Avena sativa) and wheat (Triticum aestivum) fields and trap nurseries were conducted to provide incidence and severity information and to identify the virulence structure in the pathogen populations. Stem rust samples were collected in Manitoba and Saskatchewan in 2006. Stem rust was not found on cultivated wheat and was at trace levels in barley and oat fields. From wheat and barley samples, four races of P. graminis f. sp. tritici were found and QFCSC (89%) was predominant. Thirteen races of P. graminis f. sp. avenae were found in 2006. From cultivated oat samples, the predominant races were TJJ (67%), TJS (17%), and TGD (9%). From wild oat samples, the predominant races were TJJ (40%), TGD (23%), and TGB (12%). Two new races of P. graminis f. sp. avenae (TGN and TJN) with virulence to Pg12 but avirulence to Pg13 were detected on both cultivated and wild oat both in Manitoba and Saskatchewan in 2006. [ABSTRACT FROM AUTHOR]

Previous research found that a model that used a series of Beta functions (Beta model) was better than linear models for simulating the days from seeding to seedling emergence (DSE) of wheat (Triticum aestivum L.). To further validate the Beta model we used three sets of field studies conducted in North America: (1) a seeding date study at Moro, OR (38 seeding dates); (2) a multi-year, multi-site study in Canada (98 site-years); and (3) a series of experiments at Swift Current, SK (20 treatment-years). Results demonstrated that the linear emergence module in the Cropping System Model of The Decision Support System for Agrotechnology Transfer (DSSAT- CSM) tended to underestimate DSE. The Beta model using either daily or hourly air temperature markedly improved the simulation of DSE for all three studies. The Beta model using simulated soil temperature slightly improved simulation, but was not as good as that using air temperature, which was caused by the inaccuracy of soil temperature simulation. It seems that the Beta model is an appropriate model to predict seedling emergence of wheat grown in North America. There were no significant differences in DSE among wheat genotypes used in studies at Moro or Swift Current. [ABSTRACT FROM AUTHOR]