Broomrape resistance in newly developed sunflower inbred lines

Broomrape (Orebanche cumana Wallr.) is considered to be one of the most severe constrains in sunflower (Helianthus annuus L.) production. Rapid appearance of new races requires continuous search for new sources of resistance in sunflower germplasm. The objective of this research was to screen new sunflower inbred lines, originating from different interspecific hybridisations or Russian open pollinated varieties, for broomrape resistance using different races of parasite. Newly developed sunflower cms and Rf lines were screened for resistance to broomrape in greenhouse and in field trials in two locations in Serbia, infested with the race E of the parasite, during the period 2007-2010. Research was broadened in 2011 to locations in Spain and Romania which are previously known for presence of highly virulent races F and G. Differential lines, up to race F, were planted together with selected inbred lines. Reaction of the tested sunflower lines to broomrape was evaluated by calculating incidence, i.e. ratio of infected sunflower plants per total number of plants