Yield potential of barley corrected for disease infection by regression residuals

This study was initiated to find a method to correct the phenotypic yield for the yield decreasing influence of disease infection ( = DC-yield potential). The inter-cultivar regressions of yield vs. disease infection were calculated in official trials in Germany and Austria with spring barley in 1983 and 1984 and with winter barley in 1996, 1997 and 1998, respectively. The residual of a genotype was interpreted as a measure of its DC-yield potential. The cultivar range of the DC-yield potential was 58.3% and 59.5% of the phenotypic yield range and the heritability of the residuals was about 10% below that of yield. In the spring barley experiments with and H without fungicides the individual residual remained approximately constant even when the mildew infection changed remarkably, suggesting a useful predictability of individual yield performance when the degree of infection is changed either by environment, pathotype, or resistance genes.