Table 1. Parameters of the generalized additive model examining the prevalence of genetic WCM lineages (expressed as proportion of infested shoots) in relation to the host plant species and geographic coordinates (which represent spatial variation).
| Host plant | Trend surface (spatial pattern) | |||||
|---|---|---|---|---|---|---|
| Lineage | df | Chi-sq. | p | edf | F | p |
| MT-1 | 4 | 74.34 | <0.0001 | 18.8 | 83.8 | <0.0001 |
| MT-2 | 18.7 | 17.1 | 0.5820 | |||
| MT-3 | 6 | 6918.0 | <0.0001 | 18.4 | 200.0 | <0.0001 |
| MT-4 | 13.9 | 24.0 | 0.0494 | |||
| MT-5 | 16.0 | 64.3 | <0.0001 | |||
| MT-6 | 18.8 | 31.8 | 0.0348 | |||
| MT-8 | 8 | 3140.0 | <0.0001 | 18.2 | 261.4 | <0.0001 |
| MT-9 | 17.6 | 59.8 | <0.0001 | |||
| MT-10 | 10.6 | 3.8 | 0.9750 | |||
| MT-12 | 2 | 4.4 | 0.1750 | 15.3 | 21.9 | 0.1750 |
| MT-13 | 2 | 14.7 | 0.0006 | 18.8 | 35.2 | 0.0132 |
| MT-14 | 5.9 | 2.6 | 0.8530 | |||
| MT-27 | 4.4 | 2.3 | 0.7900 | |||
Estimated degrees of freedom, “edf”, reflect the smoothness of the fitted surface. Degrees of freedom for the host plant are equal to the number of hosts that were found to infest a given lineage. If there was only one host found or two hosts among which one had only single shoot infested, this value cannot be determined, as there is no host—associated variability.