Author
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Submitted to: Phytopathology
Publication Type: Abstract Only Publication Acceptance Date: 6/6/2005 Publication Date: 6/28/2005 Citation: Cowger, C. 2005. Assessment of cultivar mixtures as a tool to manage powdery mildew disease of soft red winter wheat. Phytopathology. Interpretive Summary: Seed mixtures, or blends, of small grain cultivars have been widely used to manage foliar fungal diseases and stabilize yield. However, such mixtures are unknown in the eastern U.S. soft red winter wheat region, where powdery mildew and leaf rust regularly take a significant toll, along with other diseases and abiotic stresses. In 2003, a mixture experiment was conducted at Kinston, Plymouth, and Salisbury, NC, with four early-maturing and four medium-late-maturing wheat varieties that are grown commercially in that state. The varieties were planted in pure stands and in four 1:1 mixtures of a resistant and a susceptible variety in each maturity class. All treatments were planted in plots of both 20.4 m2 and 1.1 m2, and replicated three times for each plot size. Plots of barley, a non-host to the wheat mildew pathogen, were interspersed in a checkerboard design, and spreader rows of a mildew-susceptible wheat cultivar were planted. A moderately severe powdery mildew epidemic occurred at Kinston, where disease was assessed four times at seven- or eight-day intervals, and leaf rust severity was also evaluated at that site. Yields and test weights were determined at all locations. The quality characteristics measured were protein content, hardness, seed diameter, and falling number (a parameter related to sprouting tolerance). Technical Abstract: Seed mixtures, or blends, of small grain cultivars have been widely used to manage foliar fungal diseases and stabilize yield. However, such mixtures are unknown in the eastern U.S. soft red winter wheat region, where powdery mildew and leaf rust regularly take a significant toll, along with other diseases and abiotic stresses. In 2003, a mixture experiment was conducted at Kinston, Plymouth, and Salisbury, NC, with four early-maturing and four medium-late-maturing wheat varieties that are grown commercially in that state. The varieties were planted in pure stands and in four 1:1 mixtures of a resistant and a susceptible variety in each maturity class. All treatments were planted in plots of both 20.4 m2 and 1.1 m2, and replicated three times for each plot size. Plots of barley, a non-host to the wheat mildew pathogen, were interspersed in a checkerboard design, and spreader rows of a mildew-susceptible wheat cultivar were planted. A moderately severe powdery mildew epidemic occurred at Kinston, where disease was assessed four times at seven- or eight-day intervals, and leaf rust severity was also evaluated at that site. Yields and test weights were determined at all locations. The quality characteristics measured were protein content, hardness, seed diameter, and falling number (a parameter related to sprouting tolerance). |
