The Relationship between cross success and spatial proximity of Eucalyptus Globulus ssp. Globulus parents

The genetic structure of Eucalyptus globulus forest was examined using progeny vigor as an indirect measure of parental relatedness. Seven trees were crossed with pollen from trees: 0 m (selfing); 21 m (nearest flowering neighbors), 250 m, 500 m, 1 km, 10 km, and 100 km away from the female. Only selfing depressed seed set. Growth of the 21 m progenies was intermediate to selfing and the longer distance pollinations, suggesting tight family clusters occur due to limited seed dispersal. Under this structure biparental inbreeding may be common, however, the cumulative impact of inbreeding seems negligible as relatedness did not appear to decline with distance between mates beyond 50 m.