Comparison of two selection methods of aggressive for sunflower races of Phoma macdonaldii Boerema

Guaranteed and ecologically safe method of sunflower plants protection from Phoma pathogen is breeding of resistant varieties and hybrids. It is necessary to use aggressive isolates of a fungus for artificial inoculation of sunflower plants with Phoma macdonaldii Boerema in breeding for resistance to this disease. The purpose of our work was to compare aggressiveness of isolates of Ph. macdonaldii for sunflower which we determined with two different methods and to select the most relevant for breeding of resistant material. The researches were conducted in the laboratory of immunity and molecular marking of V.S. Pustovoit All-Russian Research Institute of Oil Crops from 2014 to 2018. We compared infection on a surface of cut-off cotyledonary leaves of 10-days sunflower seedlings after two-days placing on colonies of the different fungus isolates and toxicity of metabolites of cultural filtrate for sunflower seeds and seedlings (bio assay). Assay of Phoma isolates aggressiveness by the first method showed variability of this trait...