Genetic Aspects of Quicker Growth of Spruces and Possiblities of their Economical Exploitation

1989

S. 5-25

8 Abb., 7 Tab., 11 Lit. Ang.

Unselbständiges Werk

200047402

In the world of growing needs there waxes also the need for specific productive stand which would relax the pressure on the already overloaded forests and at the same time give better yealds because of selection. By selection with vegetative propagation we may improve the growth of stands for around 30%. With selection, mature or young trees may be chosen. In the first case we wait very long for the results of selecion, while in the second one the times are relatively short, but the genetic gain is uncertain. If we want to exploit the juvenile selection, we must know very well the correlation between the expression of a trait in youth and at mature ages, this is, the juvenile-adult correlation. Many years ago we tackled the problem of juvenile selection of fast growing spruce seedlings and we explore there further development. The results demonstrate statistically significant correlation of fast growth in more adult seedlings, though it is not clear what the dynamic of the correlatin will be after the seedlings will have grown up. The solution of this question is indicated by our own and other researches of the development of the average and the fast growing trees or populations of trees in different stands. Not only the stand of spruce but also the stands of Douglas fir and Japan larch show a highly reliabe correlation of the mode of juvenile growth and the growth of the same trees in mature stages. The regression curve, done from all disposable researches, and its extrapolation indicate we may be pretty sure about the correlation even with 50 years old trees. At the same time it is well seen it does not hold for spruce but also for other conifers. In the future the already introduced researches of juvenile selection with spruce will have to be deepened and we shall have to find the upper limit of the genetic gain with economically still justified selection differential. At the same time the comparative researches of various spruce proveniences as well as different tree species will have to be introduced.