RESISTANCE TO RHYNCHOSPORIUM-SECALIS IN 6 NORDIC BARLEY GENOTYPES

Six six-row Nordic spring barley genotypes (Hordreum vulgare L.) were assessed in the field in Finland (1994 and 1995) for resistance to Rhy nchosporium secalis (Oud.) J.J. Davis, the causal pathogen of scald, i n artificially inoculated plots. The barleys were known not to contain major genes for resistance to scald and the purpose of these experime nts was to identify quantitative differences in resistance to scald wh ich might be exploitable in a breeding programme, Disease development was monitored, grain yield and yield components were recorded, and the se data were compared with measurements taken from plants in plots kep t free of disease. Data, averaged over both years, for disease develop ment on the uppermost three leaves - areas under disease progress curv es, terminal severity and apparent infection rates - indicated that 'V erner', 'Pohto' and 'Pokko' were symptomatically significantly more re sistant to scald than 'Arve', 'Loviisa' and Jo 1599. Grain yields, tho usand-grain weights, test weights and proportions of plump grains were all significantly reduced in plots inoculated with scald compared wit h those kept free of disease;'Verner' appeared to be the most useful g enotype for use in crossing programmes to improve scald resistance in Finnish barleys.