THE MOST IMPORTANT PARASITE IN SUNFLOWER

Sunflower broomrape (Orobanche cumana Wallr.) is currently regarded as one of the most important constraints in sunflower ( Helianthus annuus L.) production. In the last 15 years, efforts to introduce genetic resistance to this parasite in sunflower hybrids were followed by the occurence of new virulent races that promptly overcame all known resistance genes. Due to this situation, most of the research efforts have focused on the development and characterization of new sources of genetic resistance to the most virulent races and also, on the genetic variability of Orobanche cumana populations. Different tests for sunflower resistance to the new races of the parasite, have showed that they are presen