Genetic parameters and their use in Scotch pine breeding
Isakov Yu. N.1, Kuznetsova N. F.1,
Mashkina O. S.1,2, Isakov I. Yu.3
1FSUE Research Institute of Forest Genetics and
Of the three levels of biological
forest diversity (genetic, specific and variety of forest ecosystems) genetic
one is the most important, complex and less studied. The last two levels are
estimated on phenotypic level but in most cases it is impossible for genetic
diversity estimation. Carrying out of breeding measures must be formed taking
into account natural genetic subdivision of woody plant species, their
populations and families and realized by use of genetic parameters. We carried
out the analysis of the following parameters: self-fertility index, cytogenetic tree peculiarities, similarity of ontogenesis
of quantitative characters and others. Distinctive peculiarity of the work is
parameter evaluation on the same models in lasing dynamics including modeling
of stress situations.
1. There was worked out a new
genetic test, showing the natural differentiation of Scotch pine by the level
of self-fertility. It is based on carrying out of self-pollination during 12
successive years on the test of the progeny received by self- and open
pollination of self-sterile and self-fertile forms on revealing of the reaction
of the mentioned forms on different stress effects on natural (extreme weather
conditions) and artificial (chemical mutagens in stimulating and inhibiting
concentrations) nature. It allowed to determine that
self-fertility character is a genetically caused parameter and its variability
represents diversity of the seed propagation systems of the population, species
and it allowed to work out the criteria of its quantitative evaluation by
self-fertility coefficient (C sf).
2. Statistically reliable
differentiations were revealed in meiosis during microsporogenesis
between self-sterile and self-fertile forms by cytogenetic
parameters (chromosome and other disturbances). The highest occurrence of microsporogenesis disturbances are characteristic for the
self-sterile forms in which structural changes in chromosomes in heterosis state predominated. Similar regularity was in the
progeny of the studied trees. It is suggested the possibility of inheritance
(preservation) of the level and specificity of chromosome pathologies.
3. There was shown the perspective
of use of dynamic description of phenotype as an independent genetic parameter
which allows by the degree of similarity of a character manifestation during
ontogenesis (linear annual increment, characters of seed productivity for the
last 12 years of observation) to distinguish some discrete groups, to describe
their frequency distribution in population and family samplings and to select
some valuable morphotypes.
Breeding decreases genetic
variability of the following generations of forest. For preservation of genetic
diversity and simplicity in population breeding (group selection) is the most
suitable. Different variants of individual selection are less suitable. On the basis of estimation of the quantity of the selected breeding material
for the following propagation and literature data on isoenzyme
analysis. There was carried out a relative arrangement of objects of
genetic and breeding complex by the level of genetic diversity and expenditures
for their organization and maintenance. The above mentioned parameters may be
used for estimation of genetic diversity of the objects of genetic and breeding
complex and selection of valuable genotypes in them.