On a genetic assessment of the adaptedness of forest reproductive material.

Abstract

Assessment of the adaptedness of forest tree populations and the reproductive material derived from them is largely based on historical records and observations on extant distributions of phenotypic traits. Genetic criteria are, if at all, usually considered only in the form of heuristic reasoning. A main reason for this situation lies in the lack of operational concepts that clearly distinguish between viability selection and adaptation. The present paper makes an attempt towards this aim by showing that the adaptational optimization of viability selection processes rests on three constituent features which allow minimization of the implied overall mortality at each relevant selection stage and across all of these stages. Indices are developed that measure the degree of adaptational optimization of viability selection. The concept and its indices are applied to an analysis of isozyme data obtained for an approved beech seed stand and reproductive material derived from this stand. An approved seed stand is required to be adapted, and this property is expected to be preserved in the derived reproductive material. Our observations revealed substantial degrees of overall reductions and suboptimal selection during the production process. Suboptimality is unevenly distributed over the stages of the production process, and stages of strongest suboptimality vary among gene loci. A preliminary explanation is given for a conspicuous effect on selective optimality that is consistently observable at the stage of seedling development across all loci.