Under model M1, parameter inference indicated that the mean number of DPD1-R variant infectious particles contributing to the infection of a pea seedling was 1.08 (with a 95% confidence interval, CI95%, ranging from 0.9 to 1.29) and 0.74 for virus variant DPD1 (with a CI95% ranging from 0.61 to 0.88), while the mean number of virus particles required to infect a pea seedling was 0.84 (CI95% = [0.63, 1.05]). The gene discussed is TGFB1; the disease is infection.