RESISTANCE IN SEMIHARDY WINTER BARLEY TO LEAF AND GLUME BLOTCH CAUSED BY STAGONOSPORA-NODORUM

Leaf and glume blotch of barley (Hordeum vulgare) was found in Georgia for the first time in 1980. Breeding lines varied significantly in susceptibility to the barley biotype of Stagonospora nodorum (syn. Septoria nodorum). Elite lines and cultivars of semihardy winter barley adapted to the southern and mid-Atlantic regions of the United States were evaluated for resistance during 10 seasons in field and greenhouse tests. Among the 214 elite breeding lines tested, 13 resistant genotypes were identified. Among the 20 cultivars evaluated, Keowee and Miller were highly resistant. Anson, Barsoy, Dayton, Henry, Milton, Perry, Preamble, and Sussex were susceptible. Highly significant correlations were detected between results over years from field and greenhouse tests. Correlations between the response on seedlings in the greenhouse and adult plants in the field were significant but low. Resistance is partial, in that all genotypes are susceptible but differ in the rate of disease development. Diverse barley germ plasm lines adapted to southern and mid-Atlantic states with a high level of resistance to leaf and glume blotch are now available.