A Field Disease Evaluation Method for Selecting Wheats Resistant to Mycosphaerella graminicola |
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| Authors: | Mohammed Jubene J P Gustafson S Rajaram |
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| Institution: | USDA, Agricultural Research Service, Plant Genetics Research Unit, Curtis Hall, University of Missouri, Columbia, MO 65211, U. S. A. (corresponding author);Aridoculture Center, National Institute for Agricultural Research, B.P. 589, Settat, Morocco;International Wheat and Maize Improvement Center, Apartado Postal 6-641, Delegation Cuauhtemoc, 06600 Mexico D. F., Mexico |
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| Abstract: | Reliable and efficient methods of selection are important for improving disease resistance. Three methods of field assessment of the Septoria tritici blotch disease, caused by Mycosphaerella graminicola (Fückel) Schroeter, were compared to identify the most reliable for selecting resistant wheats, Triticum aestivttm L. Nine cultivars which differed in disease reaction to plant height and maturity, and their progenies from several generations were used. The methods consisted of scoring chlorotic and necrotic leaf area covered with pycnidia on the flag leaf and the leaf below the flag leaf (flag leaf-1) as percent of the total leaf area, on a plant-basis, and the percent necrosis visually estimated on a plot-basis. Plot data were greatly influenced by environmental changes leading to inconsistent genetic results. The flag leaf and flag leaf-1 methods provided the most precise consistent results. The use of the flag leaf-1 method is suggested for selection. |
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| Keywords: | Triticum aestivum Mycosphaerella graminicola Septoria tritici blotch disease disease resistance selection methods necrotic leaf area plot test individual plant scores |
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