Characterizing traits that enhance the competitiveness of winter wheat (Triticum aestivum) against jointed goatgrass (Aegilops cylindrica)

Our objective was to identify traits in winter wheat important to competiti veness against jointed goatgrass, measured as increased wheat yields and re duced jointed goatgrass seed production. Jointed goatgrass is an important winter annual grass weed that cannot be controlled selectively in winter wh eat. Seven cultivars of soft white winter wheat were grown with and without competition From jointed goatgrass over two growing seasons. Measurements of numerous traits of winter wheat and jointed goatgrass were recorded thro ughout each growing season. The data were analyzed using path analysis with latent variables to determine which traits most enhanced competitiveness. In a drier year, increased rate of height development was important in main taining wheat yields when wheat was growing in competition with jointed goa tgrass. Increased rare of height development also was an important trait in reducing jointed goatgrass seed production. In a wet year compared to a dr y year, the number of wheat heads per plant, the rate of water use, and wei ght gain were positively correlated to maintaining winter wheat yields. Joi nted goatgrass seed production in the wet year was reduced overall compared to the dry year, but From the cultivars tested, there were no trails ident ified that were critical in enhancing this loss of seed production. This st udy suggests that cultivars with greater height development rates will be m ore competitive when growing in fields infested with jointed goatgrass.