Pythium Resistant Spring Wheat

Chapter 8 – Crops and Varieties, No. 6, Spring 1987

Roger Veseth

The availability of new spring wheat wheat varieties resistant to damage by Pythium root rot would be an important breakthrough for the intermediate and higher precipitation areas of the Northwest, particularly under conservation tillage systems. Cal Konzak, Washington State University agronomist and STEEP researcher, and colleague E. A. Polle, have recently identified genetic resistance to Pythium and are incorporating that resistance into advanced breeding lines of spring wheat.

The initial research was conducted in 1986 at the University of Idaho Research and Extension Center near Sandpoint. Konzak and Polle are using the low phosphorus soils at the center to select experimental lines of spring wheat for high phosphorus use efficiency and to evaluate the effectiveness of new foliar phosphorus fertilizers. The cold, wet soils were also found to support high populations of Pythium root rot fungi, allowing for the selection of Pythium resistant lines.

Experimental lines from worldwide spring wheat selections exhibited a marked variability in resistance to Pythium. Resistant lines appear to have excellent yield potential as well. Konzak found the genetic resistance to Pythium high enough to justify crossing these experimental lines with advanced lines having high quality, leaf disease resistance and yield potential in the WSU breeding program. If sufficient funding continues to be available to allow two crop selection cycles per year with a New Zealand planting, Konzak estimates that Pythium resistant lines may be ready for release as new varieties in about 6 years.

New biotechnology techniques in cereal breeding, such as anther and microspore culture, may dramatically accelerate variety development. Variety releases may be possible in about 4 years if techniques using biotechnology are successful. A visiting Chinese scientist is currently working with Konzak in this effort.