The Influence of Growing Season Conditions on the End-Use Quality of Wheat

Environmental conditions during the growing season and harvesting are responsible for differences in milling and baking quality between the various grades of Canada Western Red Spring (CWRS) wheat. This presentation provides a review of the 2002 growing season, as well as observed degrading factors and their effects on end-use quality. The 2002 growing season was particularly challenging due to drought, frost damage, and poor harvest weather. Extremely poor moisture conditions across most of the Prairies delayed planting, caused poor germination, and resulted in uneven stands in northern and central areas. Frost in early August caused damage across the same area, while frequent showers and cooler than normal temperatures during the remainder of the month extended development and promoted secondary growth. Grain filling and harvesting was characterized by wet, cloudy, and cool weather, resulting in very slow harvest progress and causing significant crop weathering. Frost in mid-September also prevented late-planted crops from fully maturing. This year’s CWRS grade profile was poorer than normal due to a number of degrading factors, most notably sprouting, frost damage, green kernels, mildew, and Fusarium damage (FD). Pre-harvest sprouting results in an overabundance of the enzyme alpha-amylase, causing excessive starch damage that in turn affects flour water absorption and dough handling properties. Frost damage and immaturity influence flour yield, flour color, water absorption, and loaf properties, and may also affect protein quality. Frost-damaged kernels also require more energy during milling due to increased grain hardness. Mildew was a much more prominent degrading factor this year due to conditions during grain filling and harvesting. Mildew may affect flour color and is considered aesthetically unappealing. FD was generally less severe than in previous years due to unfavorable conditions for disease development during anthesis. Besides being responsible for the production of the toxin deoxynivalenol (DON), which is a food safety concern, the main effect of FD is to affect water absorption, dough handling, and protein quality, or composition. Introduction The Canadian grain grading system is primarily a visual system based on a combination of subjective and objective measurements (Dexter and Tipples 1987). Environmental conditions during the growing season and harvesting are responsible for differences in milling and baking quality between the various grades of Canada Western Red Spring (CWRS) wheat (Dexter 1993). This paper provides a review of the 2002 growing season, as well as observed degrading factors and their potential effects on end-use quality. Growing Season in Review The 2002 growing season was particularly challenging due to drought, frost damage, and poor harvest weather. A dry fall and winter in late 2001 and early 2002 led to extremely poor moisture conditions for the planting of the 2002 crop. Dryness stretched from western Manitoba to the Rocky Mountains and included about 80 per cent of the cropland in Western Canada. Heading into the spring of 2002, Western Canada was the driest since the beginning of settlement of the region. Soil moisture conditions were better in eastern and central Manitoba, but topsoil moisture was less than ideal even in these areas. The extremely dry conditions, combined with cooler-than-normal weather in April and May, delayed seeding