The once dominant endemic broadleaf tree species in Taiwan, Cinnamomum
kanehirae Hay., has become a rare and endangered species due to overc
utting. A clone bank, consisting of at least 220 clones collected isla
ndwide, was established at the Liukuei station, Taiwan Forestry Resear
ch Institute. Genetic diversity within and genetic differentiation amo
ng four geographic areas of C. kanehirae were investigated using 164 c
lones collected from the clone bank. Seven out of the 11 loci examined
were polymorphic. The average proportion of polymorphic loci per area
was 51% at the 99% criterion for polymorphism. Mean expected heterozy
gosity ranged from 0.188-0.261 in the different areas, and 0.238 at th
e species level. On average the percent heterozygous loci per individu
al ranged from 13.9-21.6%, the number of alleles per locus ranged from
1.7-1.9, and the effective number of alleles per locus ranged from 1.
34-1.54 at the area level. The much higher expected heterozygosity and
higher number of alleles per locus compared to other local woody spec
ies investigated may support the hypothesis that Taiwan was a distribu
tional center of Cinnamomum. Partitioning the genetic variability into
within-and among-geographic area components with F statistics and gen
e diversity analysis led to an estimate of within-area variation amoun
ting to 88% of the total variation. A slight barrier to gene flow amon
g areas could be due to the large seed size and to insect pollination.
The limitation of seed dispersion, erratic flowering times, and sever
al subpopulations within the same geographic areas may contribute to t
he lower levels of observed heterozygosity than expected heterozygosit
y among the seven polymorphic loci, indicating some degree of inbreedi
ng and the Wahlund effect and thus a slight deficiency of heterozygote
s (F-is = 0.157). Area 4, located in southeastern Taiwan has a much lo
wer elevational distribution and showed a higher proportion of polymor
phic loci, implying that genetic variation of area 4 may have develope
d under different climate conditions.