Percentage of viable <i>Puccinia striiformis</i> f. sp. <i>tritici</i> (<i>Pst</i>) quantified by qPCR of RNA in attached leaves of six cultivars with different levels of winter-hardiness.

<p>A: 0°C; B: -5°C; C: 10°C; D: -15°C; and E: -20°C. The experiment was conducted three times. The vertical bar of each mean value represents the standard deviation of the three mean values of the three experiments; significant treatment differences were based on the pooled residual error in the repeated measurement ANOVA. The winter-hardiness cultivar treatments with different letters at the same sampling time differed significantly at <i>P</i> = 0.05.