2012 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. Using data from 2010 and 2011 field trials, we have found (1) in some cases the R-line parent has a large (positive or negative effect) on the hybrid resistance relative to developing B-lines, and (2) some of the differences in developing B-lines require higher numbers of field replications to compare to control inbreds and hybrids. As a result, we have modified our experimental approach for 2012, planting a smaller number of B-lines with test crosses to additional R-line parents, and used much higher replication than in previous years. In the coming months, we will harvest seed and stalks to quantify infestation in the field plots, and attempt to develop cost-saving methods to phenotype these samples. Analyses will also attempt to quantify physical and chemical traits facilitating insect resistance. This information 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 and biochemical 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 benefit farmers/producers.