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Tree Genetics and Molecular Breeding, 2013, Vol.3, No.2, 4
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diversity was between the populations in the orchard
while rest 92.17 per cent of total variations occurred
within the clones. The genetic distance varied from
0.012 0 (between Nilambur and Konni) to 0.025 1
(between Konni and Areinkavu). An unweighted pair
group method with arithmetic means (UPGMA)
dendrogram was constructed to represent the genetic
distances between groups of clones. One main cluster
consisted of three populations, of which Nilambur and
Konni origin trees formed one sub cluster which in
turn was linked to Arienkavu trees. The total genetic
diversity among the clones in the clonal seed orchard
was found to be 0.228 2 with 99.69 per cent of
polymorphism. The cluster analysis based on genetic
similarity coefficients of all combinations of the thirty
one clones using NTSYSpc 2.1 software generated a
unique dendrogram with six clusters. Bootstrap values
are provided at the corresponding node for each
cluster. We were unable to trace out the exact origin of
seeds used to raise those plantations as there was no
record available. The dendrogram constructed with
genetic similarity coefficient data did not yield a firm
pattern with respect to the geographic location of the
mother trees. The PCoA analysis of clones were
scattered along the coordinate axes thus, indicating
error in labeling, or mix up of stumps or suppression
of scion by root stock. A co-phenetic correlation value
(r=0.73) with bootstrap confidence values ranging
from 3.2 to 99.8 per cent for the clones in defined
clusters provided an additional support for this
labeling errors of clones in the orchard. Out of 578
ramets, there were 51 flowering ramets and 35 seed
setting ramets. The percentage of flowering was 8.8
and seed setting was 6 per cent respectively. Clone 11
and clone 31 gave germination percentage of 6.6 and
3.3 respectively. The results on seed germination
further showed that seeds from only two clones with
clone number (clone 11 and clone 31) out of thirty
five seed setting trees from 20 clones were able to
germinate. But in the present study a positive corre-
lation is observed between genetic distance and mor-
phology, negative correlation between dissimilarity
based on the relation of two morphological characters
(height of tree and Gbh) of clones observed in the
orchard. The relation between genetic distance and
phenology were negative, dissimilarity to phenology
were positive. In the CSO at Kulathupuzha, flowering
(8.8%) of trees from 27 clones and fruiting (6%) of
trees from 20 clones were comparatively very low. All
flowered clones were unable to produce seeds. Close
observation of flowering patterns within each clone
revealed that there were some odd performers with
respect to flowering and fruiting behavior of teak.
From the present study, it can be suggested that while
selecting clones for future seed orchard establishment,
it may be important to select genetically diverse clones
within a broad provenance region, such that clones
show profuse flowering and seed set. These attributes
have to be ensured while selecting candidate plus trees
or plus trees from which the clones will be developed.
Clone and ramet number should be labeled properly
during future clonal seed orchard establishment. Infor-
mation on exact origin of the ortet and data on flow-
ering, seed setting, seed viability, germination of the
ortet should be considered as essential requirement for
selecting a clone for establishing new CSO. The
genetic diversity among clones of Nilambur origin
was higher than that among teak genotypes in
Nilambur natural forests and SPAs.
Hence, the genetic diversity factor is inadequate to
explain the poor performance of seed orchards with
respect to seed production and viability. Inbreeding
(sexual reproduction among closely related individuals)
leads to homozygosity at key gene loci. Undersized
populations of different species (that are not separated
well or are constrained by uneven landscape, due to
the expression of unfavorable or deleterious alleles)
were particularly vulnerable to inbreeding depression
due to unexchange of genes with other populations.
This results in low heterozygosity leading to consid-
erable reduction in the survival and reproduction rate
of organisms. The organism neither has the potential
to foresee the future nor can be optimally personalized
for all ecological conditions. But the current genetic
composition of a species controls how well its associates
will adapt to future environment. Thus, genetic
variation plays a key role in all populations and
species to endure over evolutionary time through
altering environments.
When structuring a breeding program a breeder needs
to judge both short and long term objectives. Short