2001 The American Genetic Association 92:421–426 Heritability of Phenolics in Quercus laevis Inferred Using Molecular Markers

Studies of quantitative inheritance of phenotypes do not generally encompass the range of environmental conditions to which a population may be exposed in a natural setting and are rarely conducted on long-lived species due to the time re-quired for traditional crossing experiments. We used a marker-based method to estimate relatedness with microsatellite markers in a natural population of a long-lived oak, then used this inferred relatedness to examine quantitative genetic var-iation in the concentration of foliar phenolics. Estimating heritability using this method requires both significant relatedness and variance in relatedness over dis-tance. However, this population did not show significant variance of relatedness, so only the presence of heritability, and its ranking among traits and environments, could be estimated. Seven foliar phenolics showed a significant relationship be-tween phenotypic similarity and relatedness. The significance of this relationship varied among individual phenolic compounds, as well as by season. Genetic fac-tors appeared to have a more measurable influence on the production of secondary compounds early in the season. After leaf expansion, covariance of relatednes