The main focus of this project is to develop natural herbicides using meadowfoam (Limnanthus alba) for organic wheat (Triticum aestivum L.) cropping systems. Meadowfoam is mainly grown in Oregon and North Dakota for its seed oil. The spent seed material, meadowfoam seedmeal (MSM), contains residual amounts of glucolimnanthin, a glucosinolate and its degradation products with potential allelopathic activities that could be exploited in organic wheat farming. Although it has been shown that the glucolimnanthin degradation product, (3-methoxyphenyl) acetonitrile, contains seed germination inhibitory effects against velvetleaf (Abutilon theophrasti) and wheat, it is not known to what extent other phytochemicals in meadowfoam contribute to the allelopathic activity.
We are especially interested in the allelopathic properties of N-hydroxy-2-(3-methoxy-phenyl)-thioacetamide, a major compound we identified in MSM. Our preliminary data show that MSM water extracts inhibit germination of cheatgrass (Bromus tectorum), the dominant grass weed in Oregon's wheat producing areas. We plan to further develop the potential of MSM as a natural herbicide for weed control in organic wheat. Specifically, we would like to identify the phytochemicals that inhibit weed germination, apply MSM directly to the soil to control weeds, and explore alternative seed processing techniques that maximize the retention of high concentrations of allelopathic phytochemicals. In addition, we will explore the use of meadowfoam stems and leaves as a source of allelopathic phytochemicals for organic wheat farming.
