Morphological characteristics inPlasmopara halstedii(sunflower downy mildew)

Abstract

Morphological characteristics were studied in several Plasmopara halstedii (sunflower downy mildew) isolates of seven races. Zoosporangia and sporangiophores were analysed for P. halstedii isolates. Significant morphological differences were revealed for all pathogen isolates. Mean oval proportion was 78.3 ± 3.5%, mean zoosporangium size was 459.2 ± 30.2 μm 2 , mean sporangiophore length was 556.9 ± 36.2 μm and mean sporangiophore width was 10.3 ± 0.9 μm. Our results provide evidence that the morphology of pathogen do not correlate with both pathogenic and genetic variation.