Selection for certain phenotypic characters increases
the risk of an uncontrolled change of the genetic
resource base, thereby promoting the possibility of
diminishing the potential adaptability (Gregorius et al.,
1979; Ziehe and Hattemer, 1989). This is of special
importance in relation to the present atmospheric pollution
situation (Gregorius, 1986). Traditional forest
tree breeding is based upon the assumption, that the
local environment and its amplitude of fluctuation in
the past can be extrapolated into the future. Hence progeny
testing, which provides the basis for future breeding
populations, is basically retrospective (Larsen,
1990).
Hence, the breeding goal, in the context of stability,
aims to increase resistance by optimizing local adaptedness.
The increasing anthropogenic impact upon the
global environment (pollution and the CO2 increase
promoting a climate change) makes the occurrence of
unpredictable changes in the local growing environment
highly probable, even within the next tree generation.
Traditional breeding for maximal growth and