Screening for Disease Resistance to Foot Rot Fungi in Wheat and Barley
In the water-limited environments of Southern and Southeastern Idaho, production of dryland grain is hampered by fungal root rots that invade stress-compromised plants. There is increasing concern about adequate irrigation as we potentially enter another year with short water supplies. Simultaneously, there have been substantial changes in the U.S. grain industries. There is an increasing demand for hard white wheat in the domestic and international markets for bread and noodle products, and for specialty high beta-glucan barley varieties. These crops seem even more sensitive to disease and drought stress than their traditional counterparts. Continued effort is required to develop locally adapted wheat and barley varieties and agronomic practices that maximize productivity and profitability. Idaho?s climate provides an excellent environment to
consistently produce high quality grain. Almost 73% of Idaho?s barley received a USDA/FGIS grade of #1 in 2008 (Olson, 2008). Most grain produced in the rainfed environments of the Intermountain West suffers little from foliar pathogens that impact quality. The absence of toxin-producing pathogens in our more arid environments makes wheat and barley an excellent choice for toxin-sensitive applications, including animal feed, malt, food, and nutraceuticals. The development of new overseas markets for high beta-glucan food barley and for malt barley will expand the market options for our growers in rural Idaho. Another opportunity is offered by aquaculture with interest in grain-based fish meal. Because current varieties do not meet preferred characteristics, production will not fulfill all the needs of these new markets. We must continue to improve small grain varieties for the rainfed
environments of the West that reliably produce high quality feed for cattle, swine and fish, and provide the grain needed for growing food and malt markets. A recognized barrier to grain production under dryland conditions is the water and nutrient-robbing fungi that infect stressed root and crown tissue. Currently, breeders do not routinely screen for resistance to the dryland root rot complex, other than indirectly in variety performance trials located throughout the area. Development of a semi-permanent screening nursery at Aberdeen allows testing of varieties carrying resistance to dryland root rot fungi. In this nursery, heavily inoculated plots are dedicated to screening advanced breeder lines and testing new transgenic lines for resistance to fungal root-rotting organisms. This should advance lines for dryland areas where grains are subject to dry-land foot rot infection, as well
as provide a basic understanding of the effectiveness of transgenic and novel genes in grain to resist infection and disease expression.