Project Number: 5442-21220-024-03
Project Type: Trust

Start Date: Dec 01, 2007
End Date: Nov 30, 2010

Objective:
The objectives of the proposed research to evaluate USDA sunflower germplasm, including wild Helianthus, to find new sources of resistance to the major sunflower diseases, and to explore control strategies other than genetic resistance.

Approach:
With the aid of a full time technician and one quarter-time STEP appointment, we will search for resistance to the major sunflower diseases (Sclerotinia head and stalk rot, downy mildew, rust, Verticillium and Phomopsis), starting within USDA breeding material within the Sunflower Research Unit, and progressing to the USDA Plant Introduction cultivated and wild sunflower collection and also encompassing commercial hybrids and germplasm for foreign public research programs. Specifically we will test for downy mildew and rust resistance, using the predominant North American races, in greenhouse tests. Sclerotinia head rot and stalk rot evaluations will be done in multiple field trials, using mist irrigation (head rot) and artificial inoculations. Verticillium testing will be done both in inoculated greenhouse and field trials, while Phomopsis testing will be done solely in field trials with natural and/or artificial infection. Germplasm identified to have resistance will be given to the USDA Sunflower Unit geneticist or other unit scientists to facilitate transfer of the genes into adapted cultivated lines for eventual release, plus to other unit scientists for genetic studies.