ARS | Publication request: Inheritance of resistance to sunflower broomrape (Orobanche cumana Wallr.) in an interspecific cross between Helianthus annuus and Helianthus debilis subsp. tardiflorus

Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 6, 2011
Publication Date: February 1, 2012
Citation: Velasco, L., Perez-Vich, B., Yassein, A., Jan, C., Fernandez-Martinez, J.M. 2012. Inheritance of resistance to sunflower broomrape (Orobanche cumana Wallr.) in an interspecific cross between Helianthus annuus and Helianthus debilis subsp. tardiflorus. Plant Breeding. 131:220-221.

Interpretive Summary: Sunflower broomrape (Orobanche cumana Wallr.) is a holoparasitic plant that parasitizes sunflower roots. It constrains sunflower production in many countries around the world, especially in Central and Eastern Europe, Spain, Turkey, Israel, Iran, Kazakhstan, and China. Populations classified as race G that overcome all known resistance genes have recently appeared. Resistance to broomrape race G was identified in an accession of a wild annual sunflower species Helianthus debilis subsp. tardiflorus, and a single dominant resistance gene was transferred into cultivated sunflower background. This mode of inheritance will facilitate the introgression of resistance into elite sunflower cultivars to provide effective genetic resistance against this new and devastating new broomrape race.

Technical Abstract: Sunflower broomrape (Orobanche cumana Wallr.) constrains sunflower cultivation in increasing areas of Europe and Asia. Populations classified as race G that overcome all known resistance genes have recently appeared. The objective of this research was to study the inheritance of resistance to broomrape race G in an accession of Helianthus debilis subsp. tardiflorus identified as resistant. Heads of H. debilis were emasculated and pollinated with pollen of the H. annuus susceptible line HA 89. BC1F1, BC1F2, BC1F3, BC2F1, BC2F2, and BC2F3 generations were developed and evaluated for broomrape resistance. F1 plants were resistant, indicating dominance of resistance. BC1 populations segregated in a ratio of one resistant to one susceptible plant, whereas BC1F2 and BC2F2 populations segregated in a ratio of three resistant to one susceptible plant, which was confirmed in the evaluation of the BC1F3 and BC2F3 populations. The results indicated that resistance to broomrape race G in the accession of H. debilis is controlled by dominant alleles at a single locus. This mode of inheritance will facilitate the introgression of resistance into elite cultivars.