Effect of N:S ratio on the breadmaking quality of wheat: preliminary findings from 1999

Non-Peer ReviewedSulphur (S) is an important component of wheat proteins and, therefore, influences the quality of bread wheat. However, information regarding the role of S nutrition in Canadian Western Red Spring (CWRS) wheat cultivars under Western Canadian growing conditions is limited. Field experiments were conducted in Manitoba, Saskatchewan, and Alberta in 1999 and 2000 to examine the effect of S fertilizer application on grain yield, plant nutrient status, and bread-making quality of AC Barrie wheat (Triticum aestivum L.). Plant tissue and soil tests were also evaluated for their suitability in predicting grain yield and grain N:S ratio. Analyses of the 1999 grain samples indicated ranges of 25.3 to 38.7 mg g-1 in grain N content (14 to 22% in grain protein content), 1.3 to 2.2 mg g-1 in grain S content, and 14:1 to 23:1 in N:S ratio. Preliminary breadmaking quality analyses indicated that high ratios of N to S in grain were associated with lower loaf height, smaller loaf volume, greater dough resistance, and lower dough extensibility. Sulphur fertilization reduced grain N:S ratios at four of five sites. Of the three sites used to examine breadmaking quality, two sites showed significant improvements in loaf height and loaf volume where S fertilizer was applied. Sulphur fertilization also consistently reduced dough resistance and increased dough extensibility. The N:S ratio in grain was strongly correlated with N:S ratio in midseason tissue samples and N:S ratio in soil, calculated with water extractable NO3-S and SO4-S plus phosphate-borate extractable N and S. However, grain yield response to S was not well predicted by grain N:S ratio or spring soil test concentrations of sulphate-S

Relative performance of four midge-resistant wheat varietal blends in western Canada

Non-Peer ReviewedOrange wheat blossom midge, Sitodiplosis mosellana (Géhin), causes significant yield losses to spring wheat in western Canada in severe infestations. To mitigate losses, midge-resistant wheat varietal blends, consisting of cultivars carrying the Sm1 midge resistance gene and 10% interspersed midge susceptible refuge, have been made available to farmers. To test their performance relative to conventional midge-susceptible cultivars, four varietal blends were grown during four consecutive years, at eight locations in the provinces of Manitoba Saskatchewan and Alberta, in comparison to four conventional, midge-susceptible cultivars. Midge damage was higher in 2007 and 2010 than in 2008 and 2009. In general, the varietal blends, as a group, yielded more grain than the susceptible cultivars, especially when grown in environments with high midge pressure (5.5 - 35% seed damage). In environments with low midge pressure (0 – 2.6% seed damage), the varietal blend average yield advantage was smaller but still significant, indicating that some of the varietal blends had additional superior attributes, in addition to midge resistance

The effect of incorporating the midge resistance (Sm1) gene in wheat

Non-Peer ReviewedOrange wheat blossom midge, Sitodiplosis mosellana (Géhin), was first detected in Manitoba in 1901, but now is present in all three prairie provinces of western Canada. In severe infestations, this insect may cause significant yield losses to spring wheat. To mitigate losses, midge-resistant wheat varietal blends, consisting of cultivars carrying the Sm1 midge resistance gene and 10% interspersed midge susceptible refuge, are now available to farmers. The refuge prevents this resistance to be overcome by the insect. To test the field performance of these varietal blends, relative to conventional midge-susceptible cultivars, four varietal blends were grown during four consecutive years, at eight locations in the provinces of Manitoba Saskatchewan and Alberta, in comparison to four conventional, midge-susceptible cultivars. Midge damage was higher in 2007 and 2010, than in 2008 and 2009. In general, the varietal blends, as a group, yielded more grain than the susceptible cultivars, especially when grown in environments with high midge pressure (5.5 - 35% seed damage). In environments with low midge pressure (0 – 2.6% seed damage), the varietal blend average yield advantage was smaller but still significant, indicating that some of the varietal blends had additional superior attributes, in addition to midge resistance. Significant differences in midge damage were observed within the resistant and the susceptible groups of the cultivars tested. Midge resistance did not protect wheat against loss of market grade