Fig. 3.

Comparison of populations of Citrus exocortis viroid (CEVd) and Hop stunt viroid (HSVd) under double- or single-infection conditions over 12 seasons. The doubly infected citrus trees consisted of five blood oranges and four Murcott mandarins. CEVd singly infected citrus trees comprised two blood oranges, and HSVd singly infected citrus trees were represented by two blood oranges and two Murcott mandarins. a CEVd populations under double- and single-infection conditions. b HSVd populations under double- and single-infection conditions. The y-axis corresponds to log₁₀-transformed copy numbers of each viroid and the bars represent standard deviation errors. Statistically significant differences between values were determined by Student’s t-test (*P < 0.05; **P < 0.01; ***P < 0.001)