Adaptation and N Response of Waxy Spring Wheat Lines in Dryland NE Oregon.

Wheat starch is composed of amylose and amylopectin; amylase is made of straight chains while amylopectin is branched. Wheat with high percentage of amylopectin is referred to as ‘waxy’ wheat and this character may confer unique textures and other properties to food. This waxy character has recently been incorporated into soft white spring germplasm. However, advanced lines and ‘WaxyPen’, a recently-released variety, have been not been evaluated in the low-rainfall region of NE Oregon. The objectives of this field research were to determine the yield potential, test weight, and grain protein of ‘WaxyPen’ and two selected advanced lines and to determine the N response of ‘WaxyPen’. Variety trials were conducted in 2006 and 2007 at the Sherman (280 mm precipitation) and Pendleton (430 mm precipitation) stations of the Columbia Basin Agricultural Research Center. All trials were seeded at 22 seeds/sq. ft. using a Hege small plot grain drill; individual plots were 5 ft x 20 ft. A N response trial was conducted at Pendleton in 2006 and 2007 using ‘WaxyPen’ and ‘Alpowa’, a widely grown variety. Preplant N was applied at rates from 0 to 168 kg N ha-1 in 34 kg increments. Treatments were arranged in a randomized complete block design with four replications. Standard production practices were used in all trials. The trials were harvested using a Wintersteiger small plot combine, the grain was cleaned and weighed to determine yield, and a sub-sample was used to determine test weight and protein. Differences in yield, test weight, and grain protein were observed but no consistent differences between entries were noted. N fertilization increased yield and protein of both varieties. ‘WaxyPen’ produced slightly less grain than ‘Alpowa’ but with higher grain protein in 2006 and similar grain yields with lower grain protein in 2007.