The incidence of barley scald in cultivar mixtures

A field trial incorporating resistant and susceptible plants in mixed plots, where the proportion of resistant plants was 0%, 50%, or 100%, indicated that cultivar mixtures were not particularly effective for the control of barley scald disease. Combining 2 scald resistance genes into a single line was more effective in controlling disease than deploying the same genes singly in different lines in a mixture. The lack of benefit from mixtures in this experiment differed from the findings of 2 previous studies investigating scald resistance in mixtures. Although the study included only one growing season and one location, the findings suggest that the use of mixtures for controlling this disease may carry some risk and that breeding for a resistance pyramid is likely to be more widely effective.