Virulence and aggressiveness of sunflower broomrape (Orobanche cumana Wallr.) populations in Romania

Abstract

The pathogenic composition of broomrape populations in Eastern Europe, Turkey and Spain has changed over the years, slowly at first and then rapidly. In Romania, there are three important areas infested with broomrape (Orobanche cumana Wallr.). These areas differ in infestation degree and presence of different virulence groups. A new, highly virulent population of broomrape attacked sunflower in Romania in 2006. Many commercial hybrids belonging to different companies or to research institutes lost their resistance to the parasite in a heavily infested area near the Black Sea. The sunflower differentials set for the different races of the parasite have permited to identify a new, highly virulent population of broomrape in this area. The parasite infestation degree on the hybrids resistant to the old races has showed that this population is very aggressive. Several genotypes fully resistant to this new broomrape population have been identified in the sunflower germplasm collection of Fundulea institute. These genotypes (lines) can be used as sources of resistance genes as well as for obtaining resistant hybrids.