Submitted to: American Phytopathological Society
Publication Type: Abstract Only
Publication Acceptance Date: March 12, 2004
Publication Date: June 1, 2004
Citation: Block, C.C. 2004. Development of wild helianthus annuus populations with multiple disease resistance. American Phytopathological Society. 94:S8. Technical Abstract: Two populations of wild annual sunflower (Helianthus annuus) with multiple disease resistance were developed by recurrent phenotypic selection. Plants were selected for resistance to Alternaria leaf blight, caused by Alternaria helianthi and to Septoria leaf blight caused by Septoria helianthi. Multiple sunflower accessions were pooled to form the parental set for each population because superior resistance was infrequently found within any individual accession. Resistance was characterized by hypersensitive flecks on leaves or by small leaf spots exhibiting little of the typical chlorosis and necrosis normally observed with a susceptible reaction. Plants were concurrently selected for resistance to natural infection by powdery mildew, caused by Erysiphe cichoracearum. The A. helianthi resistance found in these populations is similar to that previously reported only from perennial species such as H. tuberosus (Jerusalem artichoke). These populations provide the opportunity to transfer resistance to cultivated H. annuus without the need for difficult interspecific hybridization. They may be particularly useful in tropical or subtropical regions where Alternaria leaf blight and Septoria leaf blight are major disease problems.