Ka. Nesbitt et al., PARTITIONING AND DISTRIBUTION OF RAPD VARIATION IN A FOREST TREE SPECIES, EUCALYPTUS-GLOBULUS (MYRTACEAE), Heredity, 74, 1995, pp. 628-637
Eucalyptus globulus is an important species for pulpwood production in
many countries. The pattern and partitioning of variation is importan
t baseline knowledge for tree breeding. Currently the species is divid
ed into four subspecies: globulus, bicostata, pseudoglobulus and maide
nii. Random Amplified Polymorphic DNA (RAPD) markers were used to anal
yse variation in 173 representatives of 37 natural populations of E. g
lobulus: 31 localities of ssp. globulus (148 individuals), two localit
ies each of ssp. bicostata (nine individuals), ssp. maidenii (ten indi
viduals) and ssp. pseudoglobulus (six individuals). Ten 10-mer primers
amplified a total of 162 scorable bands, of which 149 (91.9 per cent
were polymorphic. AMOVA analysis of a Euclidean distance matrix based
on presence/absence of polymorphic bands found most variation within l
ocalities, but significant differences between localities and regions.
Principal components analysis (PCA) identified a major latitudinal di
ne in RAPD phenotype that differentiated southern Tasmanian localities
from other ssp. globulus localities on mainland Australia. Many local
ities previously identified as intermediate between subspecies globulu
s and other subspecies in morphology were not intermediate in RAPD phe
notype. In some cases regions which showed marked differentiation betw
een localities in capsule and juvenile leaf morphology showed little R
APD differentiation between localities. RAPDs also provided new insigh
ts into the affinities of outlying localities. Although RAPD technolog
y has not yet been applied to many forest tree species, patterns of va
riation were similar to those found in other outcrossing species studi
ed using both RAPDs and other molecular markers.