Monday, November 5, 2007
68-5

Agronomic Evaluation of New Oregon Winter Wheat Varieties – Planting Date and Seeding Rate Studies.

Michael Flowers, Oregon State University - Crop & Soil Sciences, 3219 Yosemite Place, Albany, OR 97321, C. James Peterson, 231 Crop Science Bldg, Oregon State University, Oregon State University, Crop & Soil Science Dept., Corvallis, OR 97331-3002, Steven Petrie, Crop and Soil Science, Oregon State University, PO Box 370, Pendleton, OR 97801, Stephen Machado, PO Box 370, Oregon State University, CBARC Oregon State University, 48037 Tubbs Ranch Rd., Pendleton, OR 97801, and Karl Rhinhart, Oregon State University, PO Box 370, Pendleton, OR 97801.

The economic viability of Oregon wheat production depends on highly productive varieties and cost-effective sustainable management practices. Growers are continuing to adopt newly released varieties however there are little available data on how to best incorporate these varieties into individual production systems. Therefore, a study was initiated in the fall of 2005 to evaluate the performance of newer Oregon winter wheat varieties. Two study sites were established at Pendleton and Moro Oregon. The study evaluated variety performance across four planting dates and three seeding rates. The study found that planting date had the greatest effect on yield. Delayed plantings reduced yields by up to 24%. Further analysis found that there was not a variety by seeding rate interaction, indicating that all varieties performed similarly across seeding rates. Among varieties, ‘Tubbs' yielded as well or better than ‘Stephens' across all planting dates. ‘ORCF-102' was found to perform well in late plantings. The soon to be released variety ‘ORH010920' was found to have highly variable results due to its facultative nature, indicating that this variety is not broadly adapted. Among seeding rates, it was found that increased seeding rates can increase yield by up to 5 bu ac-1 in late plantings at Moro. However at Pendleton, it would not have been beneficial to increase seeding rates above 22 seed ft-2.