2013 Annual Report
1a.Objectives (from AD-416):
Evaluate selected hybrids, accessions, interspecific crosses, and lines in screening nurseries for resistance to the banded sunflower moth in North Dakota, red sunflower seed weevil in South Dakota, and stem weevil and sunflower head moth in Kansas.
1b.Approach (from AD-416):
Plots for banded sunflower moth will be located in Prosper, ND, plots for red sunflower seed weevil with be located in Highmore, SD, plots for stem weevil and sunflower moth will be located in Colby KS. Each location will contain lines, hybrids, and accessions of interest for the particular insect. Each entry will be replicated 2-4 times in a randomized complete block design. At key points in the growing season, plant tissues may be sampled for the purpose of quantifying physiological compounds that may be involved with resistance. DNA may also be sampled, as needed, for analysis. At the end of the season, seed will be sampled from the plots to assess damage from the seed infesting insects. For stem weevil, damage to stalks will be assessed, and larval counts recorded.
Sunflower is a crop adapted to a wide area of the U.S. from Texas to North Dakota. Because it is a native plant, it also has a number of native insect pests that feed on it. The purpose of this work is to find host plant resistance to insect pests that feed on sunflower in the Northern and Central Plains regions of the United States. For reasons that are not completely understood, the severity of sunflower insect pests has been declining over the last several years, particularly in primary growing areas of North and South Dakota. Consequently, insect damage levels in the large field trials historically used in this project are becoming too low to keep broad field trials as an effective or efficient primary tool of resistance screening. This result and others have been reported to the National Sunflower Association via semi-annual reports and meetings with stakeholders. While in some cases field trials may still be useful, future efforts are changing to focus on screening smaller amounts of material with known resistance phenotypes, possibly using laboratory-reared insects under semi-field (greenhouse or field cage) conditions. Results from such trials will allow us to develop improved germplasm lines with high yield and quality with insect resistance. It will also allow us to develop tools, such as genetic markers, for commercial seed companies to track resistance genes in their own breeding lines. These lines will become part of commercial hybrids in the future, which will directly benefit sunflower producers.