Submitted to: Proceedings of the International Sclerotinia Workshop
Publication Type: Abstract Only
Publication Acceptance Date: March 10, 2003
Publication Date: April 1, 2003
Citation: GULYA JR, T.J., MILLER, J.F., SEILER, G.J. DEVELOPING SCLEROTINIA HEAD ROT RESISTANT SUNFLOWER GERMPLASM. PROCEEDINGS OF THE INTERNATIONAL SCLEROTINIA WORKSHOP. 2003. ABSTRACT Technical Abstract: Early, medium and advanced generation oilseed sunflower breeding lines were evaluated for Sclerotinia head rot resistance under artificial inoculation using an automated mist irrigation system at Carrington, North Dakota, approximately 180 miles northwest of Fargo. Sources of resistance for the advanced generation lines were derived from USDA Plant Introductions, PI 548998, PI 497250, and Ames-3300. Medium generation lines were derived from European hybrids, Inedi, RO-12-13, and Dobritz demonstrated to have head rot resistance. The early generation materials consisted of two public lines from the French research agency INTA, `SD¿ and `PSC8¿, crossed with USDA high-oleic material. A severe August thunderstorm with winds of 90 k/h lodged a third of the rows prior to inoculation, but there were enough plants left to continue the evaluation of the cultivated sunflower germplasm. Resistant plants from each group will be advanced to the next generation, which will be evaluated for resistance to both Sclerotinia head rot and basal stalk rot. Sclerotinia head rot resistance was also evaluated in released interspecific hybrids, whose origins included 16 Helianthus species. Lastly, an inoculation method study was conducted on wild Helianthus using two annual (H. debilis and H. praecox) and two perennial species (H. tuberosus and H. paucilflorus). Deer preferentially ate all of the H. tuberosus flowers, leaving only three Helianthus species for testing. No classical head rot symptoms developed on any of the wild Helianthus species, presumably because of the small head. Future evaluations of resistance in wild Helianthus may need to be done on F1 crosses with cultivated H. annuus. The loss of plant material due to weather and animal problems highlights the precarious nature of relying upon one field location for evaluation.