29 based on similarity. Therefore, output of the Structure software analysis would
identify grouping of the population members better in the presence of individuals of dubious subpopulation. The Structure software was also used to evaluate the
studied oil palm populations. Results of the structure analysis using Evanno method indicates that K = 2 is the best.
Based on Structure analysis results Fig. 7, the six oil palm populations evaluated in this study are grouped into two populations, the group I consisted of
B01, A125, A127 and A140 populations and the group II consisted of B02 and B57 populations, respectively. Although it is a pisifera type of oil palm as the B02
and B57 populations, the B01 populations is grouped into the same group as A125, A127 and A140 which are the Dura type of oil palms. There are four
individuals, one belonging to A127 and three to B01 populations, which are identified as probable admixture having a fraction of group 2 genetic contributions
in the majority of group 1 genetic background Fig. 7.
Figure7. Six oil palm populations inferred from the STRUCTURE analysis. The vertical coordinate of each subgroup indicates the membership coefficients
for each individual, and the digits on the horizontal coordinate represent the group IDs in Table 1
3.3.6 Cluster Analysis of Genetic Relationship
Clustering analysis using Neighbour-Joining approach and Simple Matching Dissimilarity Matric of 148 oil palm individuals based on 16 SSR
marker loci and the resulting clustering topology is presented in Gbr. 8. The results analysis grouped the evaluated accessions of the studied oil palms into
three major clusters. The first two major clusters consist of the two T x T populations B02, and B57 while the third major cluster consists of the T x T
population B01 and admixture genotypes of the Dura Self A122, A127, and
30 A140 oil palm populations Fig. 3. The results of cluster analysis clearly show
one of the T x T populations B01 population is closely related to the Dura Self populations A125, A127 and A140.
The individual members of each of the Dura Self population did not always fall into the same sub-group but they may belong into two to four different
sub-groups. As the examples, members of A127 Dura Self population are grouped into four different sub-groups while those of A125 and A140 populations are
grouped into two different sub-groups. The admixture natures of the three Dura self populations are probably associated with the progenitors of the populations.
Individuals associated with A125 population are derived from DA10DxDA115D x DA10DxDA115D, A127 are from DA10DxDA3D x DA10D x DA3D and
A140 are from DA115DxDA3D x DA115D x DA3D parents Tabel 1.
Results of the PCoA analysis indicated that the entire 16 axis representation of 16 SSR loci evaluated were able to explain a total of 76.6 of
total variations in the populations. Moreover, the first five axis contributed to 63.73 of total existed variation in the combined populations. Almost the same
groupings are also showed based on the accession divergence among the studied six oil palm populations using PCoA. Results of the PCoA analysis Gbr. 8
indicated members of B01, B02, and B57 populations are positioned in different groups while accessions belonging to the A122, A127, and A140 are intermixed
in the same group Fig. 8, respectively.
31
Figure8. Unrooted neighbor-joining tree realized from the dissimilarity matrix. The tree shows 148 individuals of six oil palms Elaeis guineensis
populations originated from Cameroon. Accessions are identi fied by
different lines color according to the populations originated from Cameroon. Accessions are identified by diffrerent lines color according to the
populations
A125: red; A127: blue; A140: green; B01; yellow; B02: purple and B57: black
0.2 80
77 59
60 64
61 88
77
99
59 63
B02
B57
A140 A127
B01 A125
A125 A127
A127 A140
A127
