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โครงการรวบรวมและจัดทําวารสารอิเล็กทรอนิกส์ มหาวิทยาลัยเกษตรศาสตร์

16 Thai J. For. 31 (1) : 10-19 (2012)

Table 4 Genetic identity and genetic distance among six populations of Cinnamomum
porrectum based on inter simple sequence repeat (ISSR) data.

Populations Phangnga Phuket Phatthalung Satun Krabi Songkhla
Phangnga **** 0.8697 0.8949 0.8981 0.8108 0.9314
Phuket 0.1397 **** 0.8539 0.8716 0.8756 0.8948
Phatthalung 0.1111 0.1580 **** 0.9041 0.8618 0.8986
Satun 0.1075 0.1374 0.1008 **** 0.8300 0.9367
Krabi 0.2097 0.1329 0.1487 0.1864 **** 0.8677
Songkhla 0.0711 0.1111 0.1069 0.0654 0.1419 ****
Notes: above diagonal = genetic identity; below diagonal = genetic distance

On the basis of Nei’s genetic distance Conservation Implications
(Nei, 1978), a dendrogram of the six Information on genetic diversity
populations was generated using UPGMA could provide a basis for conservation and
cluster analysis. The six populations were utilization of C. porrectum. The results of
divided into two main groups (Figure 1). In this study showed that the genetic diversity at
the first group, the populations from Phuket the species level of C. porrectum was
and Krabi were clearly distinguished from relatively high when compared with other
all other populations, implying that these species in the same genus and it was not
populations were genetically more distinct regarded as endangered by the International
from the other populations. The second Union for the Conservation of Nature
group contained the remaining four populations (IUCN, 2010). Nonetheless, the habitats
of Satun, Songkhla, Phangnga and Phatthalung. are facing severe threats imposed by human
In the dendrogram, populations of the second activities, especially the expansion of rubber
and oil palm plantations. Moreover, there
group had considerably smaller genetic distances are high demands for raw materials for
and were clustered together. Within this wood carving and other products. These factors
group, the population from Satun was closer can lead to illegal cutting of C. porrectum
to Songkhla and more distant from Phangnga in natural forest. In addition, the results of
and Phatthalung, respectively. the present study showed that there was
The ISSR data results in the present very low genetic diversity at the population
study did not provide a clear-cut separation level, especially in the case of the Krabi and
among the C. porrectum populations in Phuket populations. If some conservation
relation to the origin of their respective measures are not adopted, C. porrectum will
geographical region although there was become extinct in the near future. Although
an irregular trend that accessions from in recent years, the Royal Forest Department
the same region were clustered together. has begun to carry out a conservation program
It could be that the long history of the for this species, due to the difficulty of seed
habit of this species in each population availability, the problem of a narrow genetic
might have contributed to the dispersion of base could occur in the future. Thus, an in
alleles throughout the population, lessening situ gene conservation area for C. porrectum
the influence of geography on the pattern will be established to maintain genetic diversity
and also supply seeds and seedlings for the
of variation among them.
restoration program in natural forest and for