Physiologic variation in Mycosphaerella graminicola from western Canada
Mycosphaerella graminicola (anamorph: Septoria tritici), the causal agent of septoria leaf blotch of wheat, has increased in prevalence in the prairie region of Canada in recent years. It is important to know if variation in virulence occurs in the local population as was reported in other countries. Seventy-four pathogen isolates were collected from hexaploid wheat fields in Manitoba and Saskatchewan and tested for virulence on a set of differential genotypes, including four hexaploid and two tetraploid wheat genotypes. Seedlings were inoculated with a conidial suspension and assessed 14 and 21 days later for the presence of necrosis, chlorosis, and pycnidia to identify virulence patterns. Reactions of the differential host genotypes to different isolates ranged from susceptible to near-immune. Adult-plant reactions were similar to seedling reactions for all genotypes used in this study. A difference in virulence patterns on one genotype suggested that physiological specialization occurs and that two virulence groups are present in the pathogen population from western Canada, based on the set of wheat genotypes used in this study.
speckled leaf blotch, virulence, resistance, Septoria tritici, wheat, SEPTORIA-TRITICI BLOTCH, GENETIC-VARIATION, WINTER-WHEAT, HOST CULTIVARS, SPRING WHEAT, LEAF BLOTCH, VIRULENCE, RESISTANCE, PATHOGEN, PATHOSYSTEM
0706-0661; CAN J PLANT PATHOL, JAN-MAR 2005, vol. 27, no. 1, p.71 to 77.