ALBERTA
Scald distribution and barley cultivar resistance in Alberta
K. Xi1, T. K. Turkington2, J. H. Helm1, K. B. Briggs3, J. P. Tewari3, and P. D. Kharbanda4
1Alberta Agriculture, Food and Rural Development, Field Crop Development Centre, 5030-50 Street, Lacombe, AB, T4L 1W8, 2Agriculture and Agri-Food Canada, Lacombe Research Centre, 600 C&E Trail, Lacombe, AB, T4L 1W1, 3Department of Agriculture, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, 4Alberta Research Council, Vegreville, AB, T9C 1T4
Commercial barley cultivars and differentials with varying levels of scald resistance were evaluated for scald reaction in hill plots from 1997 to 1999 at various locations in Alberta.The Rh gene in cv. Hudson, Rh2 in Atlas and Atlas 46, and Rh9 in Abyssinian and Kitchin were resistants at all locations and years, and can be used as sources of resistance by Western Canadian breeding programs. Cultivars Modoc and Trebi were intermediate in reaction to scald and, thus, the Rh42 and Rh6 genes in these two differentials may not represent effective sources of resistance. Scald reaction of commercial cultivars was significantly different among locations, suggesting that a more complicated genetic basis of resistance in commercial cultivars compared with the differentials. The resistance in commercial cultivars AC Stacey, CDC Dolly, Kasota and Seebe, held up at most locations. Most cultivars were intermediate in reaction to scald. CDC Guardian and CDC Earl became increasingly susceptible at Calmar, Lacombe and Trochu. Furthermore, one of these two cultivars was susceptible at some locations, but not others. Cluster analysis showed that the tests at different locations over years were divided into five groups based on disease reactions of 33 commercial cultivars. Groups 1 and 5 included Beaverlodge 97 and Edmonton 98, respectively, and other three groups each included the tests at several locations and years. The number of cultivars classified to be susceptible was similar within each cluster. However, the tests with similar number of susceptible cultivars were separated into different groups. The trial conducted at Stettler, Calmar and Lacombe were separated over years into groups 2, 3 and 4, indicating the differences in disease levels caused by changes in environmental conditions in different seasons. However, other trials conducted at the same locations over different years were grouped in one cluster, such as Westlock 97 and 98 in group 2, Trochu 97 and 98 in group 3 and Carstairs 97 and 99 in group 4, suggesting that scald development on the commercial cultivars is location dependent. Consequently, scald management via the choice of cultivar is dependent on location.
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