Developing Wheat Varieties for Organica Agricultural Systems

Non-Technical Summary: Our principal goal is to breed wheat varieties that are uniquely adapted to organic agricultural systems in the Pacific Northwest (PNW) that has the potential to benefit organic farming systems and breeding programs around the country. Very little attention has been paid by wheat breeders to address the needs of the organic sector. Wheat can be grown on any scale and in any environment in the PNW and most of the United States and appropriate varieties can be selected for in non-traditional wheat producing regions to improve yield, disease resistance, weed competitiveness, quality and nutrition. Our preliminary research shows that the characteristics required of a wheat variety for use in organic production is significantly different from those required for use in conventional production. Many of these characteristics may be absent from modern wheat cultivars because they generally have been bred and selected under conditions of intense chemical management. It is our goal to reintroduce into modern wheats the traits of potential value to organic cropping systems that are found in these historical wheats. <P> Approach: Our goal is to partner with organic growers in order to compare the performance of current cultivars and breeding lines under conventional and organic conditions. This diversity of management practice will be essential if we are to determine whether there are general characteristics required for organic wheat production. Field experiments for nitrogen uptake efficiency will be conducted using a split-plot design with four replications and organic nitrogen sources. Tissue analysis of aboveground plant material will provide data on biomass, nutrient uptake, concentration and partitioning. This analysis will include nutrients important to wheat yield and quality under organic systems. Breeding for durable resistance to rust requires breeding plots in several sites over multiple years. Common bunt is eliminated from conventionally grown wheat populations through chemical seed treatments. Our breeding plots do not use chemical seed treatment, and we hope to determine cultivars and lines with resistance to common bunt. In addition we will begin sending advanced lines to the dwarf bunt nursery run by the USDA-ARS. Dr. Tim Murray will assist us in screening for these two important diseases as well as in screening for eyespot and cephalosporium stripe resistance. We will use a seven parent Griffins diallel analysis and parent-offspring regression analysis to determine heritability of coleoptile length. We will determine the response to selection by selecting the top fifteen percent of long coleoptile plants and statistically comparing this with a random selection of plants for five generations. Our growth chamber coleoptile study will help us assess the correlation between field emergence and coleoptile length. We are currently conducting two experiments to determine variations in genotypic ability to compete with weeds and withstand mechanical harrowing. The first evaluates 40-60 breeding lines under certified organic conditions. This experiment compares the yield and test weight of the breeding lines under weed-free and weed intensive conditions. The second experiment is a randomized split plot design with three replications. One treatment includes aggressive harrowing with a minimum tillage rotary hoe. The other treatment is the control, using no weed management strategy. In evaluating for allelopathic root exudates, we will use the equal compartment agar method (ECAM) described in detail by Wu et al. Once varieties with high levels of allelopathic activity have been found, they will be used as parental material in crosses and progeny will be evaluated and screened for high allelopathic activity. Baking and milling tests are performed on all wheats from the organic fields. Dr. Byung-Kee Baik will perform full evaluation of bread, cookie, cake and noodles. Dr. Phillip Reeves, a research chemist with the USDA at the Grand Forks Human Nutrition Research Center in North Dakota will continue to evaluate micronutrient levels of wheat varieties and breeding lines. This will enable us to potentially improve the nutritional quality of wheat varieties through classical breeding techniques.