Figure 1. Mean transmission efficiency of BYDV-PAV and CYDV-RPV by the parental genotypes, Sg-F and Sg-C, and the F1 hybrids. Transmission efficiency was calculated as the percentage of plants infested with viruliferous aphids that became infected following a 96 hr inoculation access period. The number of recipient plants used in each experiment was 12 to 16 and the number of experiments used to calculate the means and standard errors is shown in each bar.