EVALUATION OF RESISTANCE TO SPECKLED SNOW MOLD IN WINTER-WHEAT

To select sources of resistance to speckled snow mold caused by Typhul a ishikariensis, a set of 81 wheat (Triticum aestivum) genotypes of va rious origins, 3 triticale (x Triticosecale rimpani) cultivars, and 3 rye (Secale cereale) cultivars were tested during one or two seasons. Tests were run in the field and in an unheated plastic greenhouse call ed a tunnel, in the presence and absence of added inoculum of T. ishik ariensis. In the field, inoculum was applied just before the first per manent snow cover. Plots in the tunnel were infested one month later a nd covered with fiberglass mats. Survival of inoculated wheat expresse d as a percentage of uninoculated plants, referred to as the average s urvival index (ASVI), was highest in PI 173438 (ASVI = 90%), which was equal to the index of rye cultivars (ASVI = 93%). Wheat lines from th e states of Washington and Idaho and their reselections (ASVI = 77%) w ere also resistant. These genotypes did not show reductions in biomass or grain yields. Named triticale and wheat cultivars were susceptible , with ASVI values ranging from 20% to 57%. There was a high correlati on (r = 0.81) of survival indexes between the field and tunnel tests i n the second season. This demonstrates that the tunnel technique may b e valuable to select cereal lines resistant to speckled snow mold.