Submitted to: Proceedings Sunflower Research Workshop
Publication Type: Proceedings
Publication Acceptance Date: 1/30/1998
Publication Date: N/A
Citation: Interpretive Summary: Sunflower broomrape is a serious parasite infecting the roots of plants that causes heavy losses to sunflower crops in many areas of the world. Adaptive evolution of this parasite to sunflower cultivars with resistance genes resulted in new virulent broomrape races. Sources of resistance were found in perennial wild species. This study reported the evaluation of the wild perennial sunflower species, interspecific amphploids, and the progeny generations of the amphiploids backcrossed with cultivated line against three broomrape races in Spain. Wild perennial sunflower species were found to be immune to broomrape in Spain. Interspecific amphiploids were shown to be immune or highly resistant to prevailing as well as to newly evolved virulent broomrape races. The high frequency of resistant plants in progeny generations of the amphiploids indicated that genes in amphiploids can be transferred into cultivated lines by conventional breeding method for improving broomrape resistance.
Technical Abstract: Amphiploids and backcrossed progeny populations involving perennial species H. angustifolius, H. cusickii, H. divaricatus, H. grossesseratus, H. hirsutus, H. maximiliani, H. nutallii, and H. strumosus were evaluated for Orobanche resistance in the greenhouse at Cordoba, Spain. Of the three Orobanche populations used, SE195 represented the predominant race that is susceptible to the Or5 gene, CU996 is partially resistant to Or5, and SE296 is completely resistant to Or5. Our results indicated an abundance of broomrape resistance in wild perennial Helianthus species and the resistance is under dominant gene control. Backcrossed progenies segregated for resistance as well as for chromosome numbers, and can be easily selected for further crosses. Amphiploids and backcrossed progenies resistant to these three Orobanche populations will not only provide additional resistance to the present predominant races but also offer resistance genes against the two newly identified potential future races CU996 and SE296.