Abstract:
Genetic diversity and population genetic structure of the wild rice species Oryza ru fipogon and O. nivara in Sri Lanka were studied using 33 microsatellite markers. A
total of 315 individuals of 11 natural populations collected from the wet, intermedi‐
ate, and dry zones of the country were used in the study. We found a moderate to
high level of genetic diversity at the population level, with the polymorphic loci (P)
ranging from 60.6% to 100% (average 81.8%) and the expected heterozygosity (HE)
varying from 0.294 to 0.481 (average 0.369). A significant genetic differentiation be‐
tween species and strong genetic structure within species were also observed. Based
on species distribution modeling, we detected the dynamics of the preferred habitats
for the two species in Sri Lanka and demonstrated that both O. rufipogon and O. ni vara populations have expanded substantially since the last internal glacial. In addi‐
tion, we showed that the geographical distribution of the two species corresponded
to the climate zones and identified a few of key environmental variables that contrib‐
ute to the distribution of the two species, implying the potential mechanism for eco‐
logical adaptation of these two species in Sri Lanka. These studies provided important
insights into the population genetics and evolution of these wild species in Sri Lanka
and are of great significance to the in situ conservation and utilization of these wild
resources in genetic improvement of rice.
