Michael D. Flowers, Oregon State University, Albany, OR and Nicole P. Anderson, Oregon State University, McMinnville, OR
Growers in the high rainfall production zones of Oregon are accustomed to applying plant growth regulators to seed crops. Trinexepac-ethyl (TE) is a plant growth regulator that inhibits gibberellic acid biosynthesis which has resulted in a positive effect in controlling plant height and improving yield in grass and legume seed crops. With the recent introduction of Palisade EC® in the cereal market, wheat growers are interested in using TE to increase wheat yields. In the fall of 2012, a multi-location study was initiated to determine if TE increased wheat yields in the high rainfall and irrigated production regions of Oregon. At each site a randomized complete block design with four replications was used. Treatments consisted of three wheat varieties, two nitrogen (N) rates, and four TE rates and/or timings. Preliminary results indicate that TEdid not increase grain yield or test weight with or without additional N. Additional N increased grain protein, but there was no effect on grain protein from TE. Trinexepac-ethyl applications did significantly reduce plant height. However, the timing of TE application did affect the amount and consistency of height reduction.