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term objectives usually include obtaining significant
gains in present characters of interest in the first few
generations of breeding while maintaining well-adapted
trees. Long term goal include the preservation of low
frequency alleles and control of inbreeding. A major
conflict arises between short and long term principle.
Selection strength must be high to obtain significant
genetic gains; yet maintaining uncommon alleles,
requires keeping a large breeding population in succe-
ssive generations. However, there are traditions to
structure the breeding population and make selections
to reduce this conflict. The gene resource population
represents all of the accessible genetic variation that
could contribute to the breeding population. This includes
indigenous stands, provenance trials, seed orchard
parents, progeny in progeny tests, and operat- ional
plantations. Breeding population at next level must
have adequate genetic variation to maintain genetic
gain for many generations. It has a propensity to be
more improved than the gene resource population. At
the top is the production population, consisting of seed
orchard candidates or clones used for operational
deployment. These selections are the best selections
from the breeding population and provide diversity
and genetic increase to operational plantations.
There are different types of gene resource populations,
traditionally categorized as either in situ or ex-situ. In
situ conserving techniques involve on-site conservation
of genetic resources in native habitats; while ex situ
techniques involve storing genetic resources in special
collections such as seed banks, progeny or provenance
tests, and seed orchards. Both in situ and ex situ man-
agement are important in maintaining genetic diversity
for a breeding program. They vary in effectiveness
depending on objective, origin, species, intensity of
management, size of a population, etc. One important
measure of efficiency is whether a group has a power
over the particular gene resource population. Clonal
Seed Orchards are long term populations; one needs
some control over these populations to ensure they
will be obtainable in the future.
Authors Contribution
P.M. Sreekanth made substantial contributions to conception
and design, or acquisition of data, or statistical analysis
and interpretation of data; have been involved in drafting
the manuscript or revising it critically for important
intellectual content; and have given final approval of the
version to be published. M Balasundaran made acquisition
of funding, collection of data, design of study and
general supervision of the research group and analysis
and interpretation of data.
Acknowledgements
The authors acknowledge the financial support provided by
the Department of Biotechnology, Government of India
(S.O.No.BT/PR/2302/AGR/08/161/2000). We are thankful
to the Forest Departments of Kerala for giving permi-
ssion for the collection of leaf materials and seeds for our
research.
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