Screening wild sunflower species and F1 interspecific hybrids for resistance to broomrape

Broomrape has become one of the most important threats to the cultivated sunflower. New sources of resistance genes are needed to maintain sunflower production. The objective of this research was to evaluate accessions of wild sunflower species and their F1 interspecific hybrids with cultivated sunflower for resistance to race E. Plant material consisted of 6 accessions of perennial species and 14 F1 accessions between perennial species and cultivated sunflower as well as 42 accessions of annual species. Cultivated line JM8 was used as the sensitive check. Accessions were screened in the greenhouse in the season of 2008/09 and in a field trial during 2009. Plants were grown in the infested soil and evaluated for reaction at the end of the vegetation. The cultivated check was susceptible in the greenhouse and in the field trial. The annual species showed varying resistance with H. annuus and H. argophyllus as the most sensitive with an average of 6.6 and 8.5 broomrape plants per sunflower plant. Only 2 of the 7 H. petiolaris accessions were susceptible. H. neglectus performed well in the greenhouse with only one broomrape plant infecting one plant of the four tested accessions, but accession NEG1363 was infected in the field trial leaving NEG457 and 1183 as resistant. All accessions of perennial species except for an F1 hybrid of DEC B and F1 RIG 707 showed complete resistance. New potential sources of broomrape resistance genes have been found among wild species and their interspecific hybrids