Registration of 'Xerpha' wheat.

Many of the current soft white winter (SWW) wheat (Triticum aestivum L.) cultivars produced in Washington are adapted to specifi c environments. The objective of this research was to develop a high yielding, disease resistant SWW cultivar with competitive yield potential for all Washington winter wheat production environments. 'Xerpha' (Reg. No. CV-1045, PI 645605) SWW wheat was developed by the Agricultural Research Center of Washington State University (WSU) and released in 2008. It was selected from an 'Eltan'/'Estica' cross made in 1999 and advanced to the F 5 in the greenhouse by a modifi ed single seed descent breeding strategy. Successive progeny were advanced under fi eld conditions by a modifi ed pedigree-bulk breeding method under the experimental designations SSD01061 and eventually WA007973. Xerpha was the highest, or among the highest, yielding SWW cultivars in every precipitation zone in the WSU Extension Uniform Cereal Variety Testing Program (EUCVTP) trials in 2006, 2007, and 2008. It was released as a replacement for 'Madsen' and Eltan on the basis of its superior grain yield in Washington's low ( 500 mm AAP) precipitation zones; excellent grain volume weight; strong cold tolerance, and high-temperature, adult-plant (HTAP) resistance to stripe rust (caused by Puccinia striiformis Westend. f. sp. tritici).