PLANT BIOTECHNOLOGY
Biotechnology comprises any technique that uses living organisms to make or modify a product, to improve plants or animals or to
develop micro-organisms for specific uses.
TREE IMPROVEMENTTree improvement relies on understanding and using variation that
naturally occurs in tree populations.
Tree improvement increases the value of a tree species by
1) selecting the most desirable trees from natural stands or
plantations,
2) breeding or mating these select trees.
3) testing the resulting progeny.
TREE IMPROVEMENT PRIORITIES
The establishment of initial
populations, including
species and provenance testing, as well as the
development of breeding
and gene conservation
populations;
Population improvement, frequently including recurrent
cycles of selection and
recombination.
The general objective of a
genetic improvement
Programme should be the sustainable management of
genetic variation to
produce, identify and
multiply for the operational
planting of well-adapted genotypes of the desired
quality.
TECHNIQUES OF TREE IMPROVEMENT
CRYOPRESERVATION AND IN VITRO STORAGE
This comprises the maintenance of cells,
tissues or organs in cultures where growth is slowed (e.g. by the reduction of
light, temperature or nutrients) or suspended (by immersion in liquid
nitrogen).
MAINTENANCE OF JUVENILITY
Suspension of the growth process implies the
maintenance of the maturation state previously
attained in the tissues -without any of the
uncertainty associated with alternative strategies such as long-term hedging or
serial propagation.
TECHNIQUES OF TREE IMPROVEMENT
USE OF MOLECULAR
MARKERS
The use of molecular markers involves the
examination, using
sophisticated biochemical
techniques, of variations in
cellular molecules such as DNA and proteins.
Genetic fingerprinting.
Quantification of
genetic variation.
The major current value of molecular markers lies in long-term strategic research;marker studies are making great contributions to advances in the understanding of
basic genetic mechanisms and genome organization at the molecular level.
GENETIC ENGINEERING
This comprises the insertion of novel genes into a plant or else
the modification of existing
genes through manipulation of
the DNA molecule.
TECHNIQUES OF TREE IMPROVEMENT
It is important that genetically engineered genotypes be of high quality with respect to other traits as well.
The clonal test is the most logical basis for the integration of genetic engineering into traditional tree improvement programmes.
Genetic engineering is most appropriately conducted with species for which breeding programmes are advanced and clonal forestry can be realistically contemplated.
MICROPROPAGATION
This refers to in vitro plant
propagation methods.
The principal approaches are
axillary budding (actually a
miniaturization of propagation
with cuttings):
Induction of adventitious buds
on non-meristematic tissue (i.e.
inducing a shoot where one
would not normally develop).
TECHNIQUES OF TREE IMPROVEMENT
Somatic embryogenesis (where
individual cultured cells or small
groups of cells undergo
development resembling that of
the zygotic embryo).
Work done with some crop
species indicates the possibility of
encapsulating somatic embryos
to form artificial seeds which can
then be handled like
conventional seeds.
CONCLUSION Modern biotechnology should be perceived as a new group of
tools or means to be used as adjuncts or complements to
conventional technologies in solving problems and meeting the
needs of human beings.
A balance should be maintained between modern
biotechnological and conventional research, and the development
and application of biotechnology should be driven by needs and
not by technological capability.