Cm. Hardner et al., THE RELATIONSHIP BETWEEN CROSS SUCCESS AND SPATIAL PROXIMITY OF EUCALYPTUS-GLOBULUS SSP. GLOBULUS PARENTS, Evolution, 52(2), 1998, pp. 614-618
The genetic structure of Eucalyptus globulus forest was examined using
progeny vigor as an indirect measure of parental relatedness. Seven t
rees 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 proge
nies 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, th
e cumulative impact of inbreeding seems negligible as relatedness did
not appear to decline with distance between mates beyond 50 m.