I just received an email from Jim Peterson, OSU Wheat Breeder, in which he explains how the genetic disease resistance present in both Goetze and Tubbs06 actually works. For any further information, Jim recommended we contact Chris Mundt, OSU Plant Pathologist. I am re-posting an excerpt of Jim's email here, with his permission of course.
Please note that both Goetze and Tubbs 06 carry genes for HTAP (high temperature adult plant) resistance to stripe rust. Goetze, in fact, carries the Yr29 gene for adult plant resistance, plus others.
HTAP resistance generally kicks in when night temperatures are above 50 degrees and day temps are above 68 degrees, and plants are in, or near, adult plant stage. The temperature effect on expression of HTAP resistance is not clear-cut, but varies with number of genes, plant development stage, and day vs night temperatures. Heavy inoculum and cool conditions can cause high rust severity on plants with moderate levels of HTAP resistance (such as Tubbs 06).
It is early to expect HTAP resistance to be fully effective. An early season infection, as you have recently found, is certainly possible. However, we would expect HTAP resistance to kick in soon and reduce the chance of spread.
Jim also pointed out that "the cycle for stripe rust (infection to sporulation) is about two weeks." The newer leaves on the infected plants we have been finding are, at this point, still relatively free of disease. With the disease resistance kicking in as the day and nighttime temperatures increase, we should not see rapid disease spread at this point. Trust me however, we'll be keeping an eye on it.
A big thanks to Jim Peterson for explaining the resistance mechanism so clearly and concisely.