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Quality Response of Twelve Hard Red Winter Wheat Cultivars to Foliar Disease Across Four Locations in Central Kansas ¹

¹Contribution No. 97-352-J of the Kansas Agricultural Experiment Station. ²Graduate student, assistant professor, Department of Grain Science and Industry, Kansas State University, Manhattan, KS 66506-2201. ³Corresponding author. E-mail: tjh@wheat.ksu.edu Phone: 913/532-4082. Fax: 913/532-4017. ⁴Professor, Department of Plant Pathology, Kansas State University, Manhattan, KS 66506-5520. ⁵Assistant professor, Department of Statistics, Kansas State University, Manhattan, KS 66506-5520.

Twelve hard red winter wheat cultivars were grown at four locations in central Kansas to evaluate the role of foliar fungal diseases on wheat end-use quality in 1995. Disease was allowed to develop naturally on control plots and was controlled partially on plots treated with a systemic fungicide. After harvest, wheat samples were evaluated for the impact of the disease complex (leaf rust, tan spot, speckled leaf blotch) on physical grain quality, grain protein, milling properties, flour absorption, and peak mixing time. Data were analyzed using a mixed model to account for random (location and block) and fixed (cultivar and fungicide) effects. Location significantly influenced quality characteristics except kernel size and peak mixing time. The magnitudes of variation among random effects on all quality characteristics were larger for location than for the interactions between location × cultivar and location × fungicide. The fixed effects portion of the analysis revealed that the cultivar × fungicide treatment interaction significantly affected test weight, kernel protein, and flour absorption. Fungicide treatment resulted in significant increases in yield and kernel weight. Cultivar significantly affected all quality characteristics except kernel size and peak mixing time. Disease resistance exerted a significant influence on yield and test weight. The economic benefit associated with improved wheat quality from fungicide treatment was variety specific. Three cultivars (TAM 107, Karl 92, and Ike), which account for 50% of the 1997 planted wheat acres in Kansas, demonstrated positive improvements in test weight and protein in response to fungicide treatment.