Variation in Virulence Within the Population of<i>Pyrenophora tritici-repentis</i>in New York

Abstract

(...) Isolates did not differ widely, indicating only a moderate degree of physiologic specialization in the populations of P. tritici-repentis under study. Similarity of wheat cultivars was also determined based on their patterns of resistance to 17 isolates of P. tritici-repentis. Winter wheat cultivars currently grown in New York possess moderate to high resistance, whereas spring wheat cultivars are susceptible to P. tritici-repentis. For wheat breeding purposes, screening wheat genotypes with a few virulent isolates may suffice in selection for a moderate level of resistance to P. tritici-repentis. Cluster analysis may be a useful tool to discern similarities among pathogen isolates and among host genotypes in quantitative host-pathogen systems, but experimental variation may influence cluster composition