The 2015 growing season was challenging for wheat producers in many areas of the state. Drought early, excessive rain and heavy disease pressure where just a few of the issues facing this year’s crop. As growers wrap up harvest, thoughts often turn to planning for the next season. Selecting which varieties to grow next year is one of the most important decisions in this planning process. At some fundamental level we are all drawn to the varieties with the highest yields. Keep in mind, however, that there are many factors supporting the productivity of a variety. The 2015 season serves as a valuable reminder about the value of disease resistance in wheat varieties.
K-State just released an updated version of the annual publication that summarizes the reaction of wheat varieties to the most common disease and insect problems in the state. This publication incorporates disease observations from more than 30 locations around the state, including county variety demonstration plots and variety performance tests. This year's revision focuses on improved ratings for stripe rust, leaf rust, wheat streak mosaic, and Fusarium head blight (head scab).
A comparison of the yield of varieties with different levels of stripe rust resistance suggests that genetic resistance is very important when the disease pressure is high. Having a variety with genetic resistance can result in a yield advantage of 20 bushels per acre. Of course, there is more to a good wheat variety than disease resistance, but in years like this the value of the genetic resistance is clear.
You can access the revised publication Wheat Variety Disease and Insect Ratings, 2105 at:
Figure 1. A comparison of yield (bu/acre) for wheat varieties with different levels of genetic resistance to stripe rust. Varieties with a rating of 1-2 are highly resistant to stripe rust. These data are from the K-State variety performance tests in Greeley and Thomas counties. The Greeley County location was dryland and the Thomas County location was irrigated.
Erick De Wolf, Extension Plant Pathology