Sunflower Broomrape (Orobanche cumana Wallr.)

The closely related genera Orobanche and Phelipanche, known as broomrapes, encompass around 170 holoparasitic plant species mainly distributed in the northern hemisphere, with greatest diversity in the Mediterranean region and Western Asia. One of the most important weedy species is O. cumana Wallr., which parasitizes exclusively sunflower crops. Due to its host specificity, O. cumana is commonly named as sunflower broomrape. Broomrapes are very destructive weeds, with yield losses close to 100% under high infestations. Sunflower broomrape has great capacity of dispersion and mutation. Sunflower broomrape can be controlled by post-emergence application of Imidazolinone (IMI) herbicides on non-Genetically Modified Organism (GMO), IMI-tolerant hybrids, derived from resistance alleles identified in wild populations or developed by mutagenesis. This chapter discusses the current status of sunflower broomrape infestations and race evolution around the world, recent research advances in the biology and genetics of the parasite, and current strategies and future prospects for sunflower broomrape control through exploiting sunflower genetic resistance to either broomrape or IMI herbicides.