M. Rossetto et al., DNA-FINGERPRINTING OF EUCALYPTUS-GRANITICOLA - A CRITICALLY ENDANGERED RELICT SPECIES OR A RARE HYBRID, Heredity, 79, 1997, pp. 310-318
Eucalyptus graniticola is known from a single plant located on a grani
te outcrop south-east of Perth in Western Australia. Since its discove
r: in 1987, it has been uncertain whether this eucalypt is a relict sp
ecies or a hybrid and, consequently, further study is required in orde
r to devise appropriate conservation strategies. The similarity of fea
tures, such as leaf, bud and fruit morphology, to those of E. rudis, a
common tree found in the vicinity, suggested that E. graniticola is a
hybrid. This study uses random amplified polymorphic DNA (RAPD) analy
sis to demonstrate the additive inheritance of DNA markers from E. rud
is and E. drummondii, the putative parent species, in E. graniticola.
All the markers detected for E, graniticola using nine primers were sh
ared with either E. rudis (40 per cent), E. drummondii (35 per cent) o
r both parent species (25 per cent). The DNA fingerprinting results, c
ombined with other factors, such as the segregation of cotyledon morph
ology, demonstrate the hybrid origin of E. graniticola. As a result, c
onservation of this rare eucalypt should rely more on ex situ propagat
ion and storage than on active management.