Fig. 2

Relationship between the Ustilago nuda infection observed in the field and measured with laboratory detection methods: (A) embryo test and (B) qPCR method Observed field infections, used as the reference infection level for each sample obtained from naturally infected seed lot or their mixtures, are plotted on the x-axis as the independent variable. The U. nuda measurements from the laboratory detection methods that are evaluated in this study are plotted on the y-axis as dependent variables. The linear models’ lines of best fit between field observation and the laboratory detection methods are illustrated with black dotted lines. The linear model equations, \(R^{2}\), adjusted \(R^{2}\) (\(R^{2}\) adj), and p-value are shown in the top left corner of each plot. Each sample from each cultivar was sown in two of the three field growing seasons. The different shapes indicate the two years of observed field infections for each sample, and the average infections of each sample are shown as a circle. In both plots, the red vertical dashed line indicates the field tolerance threshold value (35 ears per 100 m²).