Effect of scald (Rhynchosporium secalis) on yield and yield components of twelve winter barley (Hordeum vulgare) genotypes

Graduation date: 1990The effects of scald epidemics, induced by Rhynchosporium secalis\ud (Oud.) Davis, on the yield and quality of winter malting barley have not been\ud reported. The principal objective of this investigation was to assess yield and\ud quality losses in resistant and susceptible winter barley genotypes in diverse\ud environments of the Pacific Northwest region of the United States. As\ud consistent, uniform infection is required for resistance breeding, three\ud inoculation methods were compared with a fungicide-protected check. Disease\ud development was poor at one location (Pendleton) and excellent at the second\ud (Corvallis). Yield reductions at Corvallis ranged from 27-40%. Resistant\ud genotypes showed lower disease severities, and yield losses than susceptible\ud genotypes. Natural infection was as effective in generating epidemics as\ud infected straw or spore inoculation. Of the yield components, the number of\ud spikes per unit area was the most affected by scald. There were no consistent\ud effects of disease on grain weight, although kernel plumpness was reduced\ud under disease pressure. Genotype x environment interactions were\ud pronounced. Resistant genotypes were higher yielding than susceptible\ud genotypes in fungicide-protected plots under disease pressure. The opposite\ud was true under minimal disease pressure