Integration of Conservation Strategies of Plant Genetic ... - Genres

New Approaches to Evaluation of Genetical Structure of Plant Populations for in situ and ex situ
Conservation of Plant Genetic Resources
V. A. DRAGAVTSEV 1
It is shown that besides the mechanism of differential activity of genes, which is induced, on the one
hand, by the law of ontogenesis, while on the other hand, by environmental stresses, there exists the
mechanisms of redetermination of genetical formulae of quantitative characters in different environments
[1, 2]. On the basis of this mechanisms we created a new ecogenetical model of organization of
quantitative characters [3, 4]. Using this ecogenetical model, it is possible to explain and predict the
behaviour of many important genetical parameters of populations in different environments against the
background of different limiting factors. From the standpoint of the ecogenetical model, the theory of
polygenetic inheritance, developed by K. Mather [5], is a weak model without scientific prediction of
changes in genetical parameters. Our model shows that now there are no good methods for genetic
analysis of quantitative characters. It is impossible to have a stable "passport" of genetical structure of
any quantitative character for any environment.
We have withdrawn from studying the genetics of quantitative characters. Now we study the genetical
organization of the following six genetical-physiological systems:
1. Genes of attraction (attr)
2. Genes of micro-distribution of attractive plastic substances (mic)
3. Genes of adaptivity (cold, drought, frost, salt resistance) (ad)
4. Genes of "feed paying" (i.e. efficiency of using nitrogen, phosphorus, etc.) (ef)
5. Genes of tolerance to density in phytocenosis (tol)
6. Genes of variability of parts of ontogenesis (ont)
Together with A. Djakov we carefully studied the reasons of the success of best breeders, such as
V.Pustovoit, P. Lukjanenko and others [6]. Each of them used one from six genetical systems for radical
improvement of species.
We found the phenomenon of orthogonality in the effects of genes and effects of environmental factors
in determining the coordinated of characters. With the help of this phenomenon, it is possible to
delimitate very quickly the contribution of genes and environmental contribution to the level of a
quantitative character. For example, see Fig. 1.
On the background of this approach we developed the new methods of creating core collections of selfpollinated
crops. For example, in the Institute's collection we have about 40,000 samples of bread wheat.
The core collection of genes of attraction (Fig. 1) should have about 400 samples, while the best
genotypes - about 50 samples, which would make the working collection for plant breeders. A working
collection for six genetical systems should be about 300 to 40 samples.
These methods are very interesting for analysis of natural populations. The focuses with maximum
1
Author's address:
N.I. Vavilov Research Institute of Plant Industry (VIR)
42-44, B. Morskaya Street
St. Petersburg 190000
Russia