Danger of new broomrape races for sunflower in Russia and measures for possible damage prevention

It is stated that overcame due to gene Or3 sunflower resistance broomrape individuals may be considered as plants of race D only after verification of progenies virulence. This fact and theoretical analysis prove, that recommendation to repress virulent races during unrestricted long time by stabilizing selection for rising of race C concentrations in broomrape populations is erroneous. Established situation demands to take prompt actions race status of broomrape populations in Russia regions study and for providing sunflower breeding with resistance sources. For broomrape races identification not anatomical characters of parasite individuals aggressiveness must be used, but international genotype-differentiators scale.