Project Number: 5442-21220-024-02
Project Type: Specific Cooperative Agreement

Start Date: Jul 01, 2007
End Date: Jun 30, 2012

Objective:
The goals of this project are (1) to find new sources of Sclerotinia stalk rot resistance in cultivated sunflower germplasm, (2) to study the relationship between tissue calcium levels in wild Helianthus and cultivated sunflower and resistance to Sclerotinia stalk rot, and (3) to transfer Sclerotinia resistance by conventional breeding and marker-assisted selection (MAS) into elite USDA sunflower germplasm for release to the public. Specifically, the project will (1) evaluate new cultivated sunflower accessions of the USDA Plant Introduction Station's seed collection for resistance to head and stalk rot, (2) evaluate the tissue calcium levels of cultivated sunflower with varying levels of Sclerotina resistance, and (3) cross new sources of Sclerotinia resistance into elite oilseed and confection USDA germplasm.

Approach:
To increase the genetic diversity of Sclerotinia resistance within the USDA breeding program, we will evaluate both the newest USDA Plant Introductions (which have not been tested for disease resistance) and seek new germplasm via exchanges with foreign public breeding programs. The evaluations will be done with artificial inoculations at multiple test sites in North Dakota and Minnesota. Once new sources of stalk rot resistance are identified, we will determine with the aid of MAS whether these contain new genes. Once resistance sources are identified, they will be crossed into either elite oilseed or confection lines. Calcium tissue levels will be studied in hybrids and Plant Introductions of known Sclerotinia resistance to allow correlation between the two traits. Additionally, calcium evaluations of a limited number of wild annual Helianthus species will be done to determine the genetic variability within the wild species.