Results (1987-1989) of virulence analysis in barley mildew in the former GDR [powdery mildew]
1991
Gabler, J. | Fritsche, H.
Virulence analysis in barley mildew has been carried out at several locations in the former GDR since 1978. At the same time the portion of cultivar mixtures of spring barley has increased to about 90%. The frequencies of virulences Va6, Va12 and Vg+V(CP) were about 100% in the three years, followed by V(La) and Va7+V(Ab) with intermediate frequencies. The virulences Vp, Va13+?, Va9 and Va13 occurred at frequencies 40%; Va3 and Va7+ Vspiti 20%; and Vo 10% on an average of years and locations. Thc virulences Va7+V(Ab), Val3, Va9, Va7+Vspiti and Vp showed a continously increasing tendency, whereas virulence Va3 decreased from 1987 to 1989
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