NEWSLETTER 2, December 2018

The parasitic plant Orobanche cumana Wallr. is the most important biotic constraint to the production of sunflower crop, in all countries where sunflower is grown, except North and South America.

The parasitism of O. cumana on sunflower dates back to the first half of 19th century in Russia, expanding to Moldova and Romania by the beginning of 20th century and later in others like Turkey, Spain, Serbia, Bulgaria and Ukraine. Currently, O.cumana is present in all countries in Southern Europe and areas around Black Sea, as well as in many countries in Asia.

The first mention to different races within O. cumana dates back to the beginning of 20th century, in Russia, by breeders developing sunflower varieties genetically resistant to races A and B. Later (1970-1980) in Romania there have been identified other three races: C,D,E as well as a set of sunflower genotypes, each of them carrying one single major gene of resistance. Races A to E were effectively controlled through genetic resistance for some decades, until race F has been identified.

Along the last decades, a new break of the genetic control of O. cumana has occurred in Turkey, Romania, Bulgaria, Russia, Ukraine, Spain, as a consequence of the crop intensification and short crop rotation, together with the use of genetic material from foreign breeding programs. There have been identified new highly virulent races, as G, H or more. Because in the last years, in China sunflower was growing very much as an oil crop, also as confectionery type, broomrape parasite has developed new races. The appearance of new races considerably reduced the available sources of efficient resistance of cultivated sunflower. A high level of resistance was found in wild Helianthus spp., mainly in perennial ones.
Important efforts of breeders are devoted to the search of effective resistance against the increasingly virulent parasite populations and, as a result, resistant genotypes have been released. Broomrape control can be also managed by development of IMI resistant hybrids or by using biological control.

Dr. Maria Joita-Pacureanu

Principal Researche

Sunflower Breeding Department, NARDI Fundulea, Romania

NEWSLETTER December 2018