Location: Sunflower and Plant Biology ResearchTitle: Registration of the oilseed restorer sunflower germplasms RHA 472, RHA 473, RHA 474, and RHA 475, possessing resistance to Sclerotinia head rot Author
|Gulya, Thomas - Retired ARS Employee|
Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2015
Publication Date: 4/10/2015
Citation: Hulke, B.S., Gulya, T.J. 2015. Registration of the oilseed restorer sunflower germplasms RHA 472, RHA 473, RHA 474, and RHA 475, possessing resistance to Sclerotinia head rot. Journal of Plant Registrations. 2:232-238. doi:10.3198/jpr2014.12.0084crg.
Interpretive Summary: Four inbred lines were released which combine Sclerotinia resistance and Phomopsis stalk canker resistance together with good yield potential, favorable fatty acid composition, herbicide tolerance, and good general agronomic quality. Data was obtained over four years resulting in the selection and release of these four lines from four different genetic backgrounds. This work was conducted to fulfill the mission of our research unit and that of the National Sclerotinia Initiative – to develop, release, and register lines for public use that combine the best yield and agronomic traits with Sclerotinia resistance. These lines will be useful for breeders around the world to use in improving hybrids distributed in the USA and elsewhere. The lines are publicly released, and no plant variety protection or plant patent applications will be submitted.
Technical Abstract: The most significant disease threat to sunflower production in most of the world is Sclerotinia head rot (HR), caused by the necrotrophic pathogen Sclerotinia sclerotiorum (Lib.) de Bary. Resistance to Sclerotinia is available in some inbred lines, but no line or hybrid is immune to it and all resistance is quantitatively inherited. There is also a lack of sunflower germplasm with high yield potential, good agronomic performance, and seed quality traits with Sclerotinia resistance. Herein, we describe the development and release of four germplasm lines that each has Sclerotinia HR resistance, competitive yield and oil content, good agronomic performance, and adaptation to the Northern Great Plains of the U.S. and similar regions. RHA 472 (PI 670490), RHA 473 (PI 670491), RHA 474 (PI 670492), RHA 475 (PI 670493) are restorer inbred germplasms that were developed using the pedigree breeding method with early generation testing for herbicide tolerance and fatty acid composition in the seed oil, and testcross hybrid evaluation in later generations for Sclerotinia resistance, yield and oil content, and agronomic performance. RHA 473 has high oleic acid in the seed oil, and RHA 474 and RHA 475 possess tolerance to imidazolinone herbicides. These lines were released by the USDA-Agricultural Research Service and the North Dakota Agricultural Experiment Station, Fargo, ND, to fill the urgent need in the sunflower industry for breeding lines with disease resistance in an elite genetic background.