RAPD, RFLP, nuclear SSLP and chloroplast SSLP analyses were carried out to
clarify the phylogenetic relationships among A-genome species of rice. In t
otal, 12 cultivars of Oryza sativa (4 Japonica, 3 Javanica and 5 Indica), o
ne cultivar of O. glaberrima, and 17 wild accessions (12 O. rufipogon, 2 O.
glumaepatula, 1 O. longistaminata, 1 O. meridionalis and 1 O. barthii) wer
e used. Their banding patterns were scored and compared to evaluate the sim
ilarity between accessions. Genetic differentiation within and between taxa
was examined based on the average similarity indices. Except for chloropla
st SSLP analysis, the average similarities were higher within O. saliva tha
n within O. rufipogon, and O. saliva Indica had greater intrasubspecific va
riation than Japonica and Javanica. Comparisons between cultivated and wild
species showed that O. saliva was closely related to O. rufipogon, while O
. glaberrima was closely related to O. barthii. This indicated that two cul
tivated species, O. saliva and O. glaberrimia, originated from O. rufipogon
and O. barthii, respectively. Domestication of O. saliva seemed to be diph
yletic, since strong similarity was observed between O. saliva Japonica-Jav
anica and O. rufipogon from China and between (3. saliva Indica and O. rufi
pogon from tropical Asia. In addition, dendrograms for RAPD, RFLP, and nucl
ear and chloroplast SSLP analyses were constructed to reveal the overall ge
netic relationships among A-genome species. In all analyses, O. saliva and
O. glaberrima formed groups with O. rufipogon and O. barthii, respectively.
However, their manners of clustering with other wild species were not the
same. The results of RAPD and RFLP analyses indicate that O. glumaepatula w
as relatively close to the groups of O. saliva and O. glaberrima whereas O.
longistaminata and O. meridionalis were highly differentiated from other A
-genome species. On the other hand, clear interspecific relationships were
not obtained by nuclear or chloroplast SSLP analyses.