HETEROZYGOSITY AND BIOMASS PRODUCTION IN SALIX ERIOCEPHALA

The relationships between heterozygosity at 11 variable isoenzyme loci and total above-ground leafless biomass production were examined in f our full-sib families of Salix eriocephala, a willow species important in short-rotation intensive-culture feedstock plantations. Relationsh ips were investigated by comparing the performance of heterozygotes wi th that of corresponding homozygotes in locus-by-locus comparisons, by investigating multiple regression models with individual loci as inde pendent variables, and by employing the adaptive distance model. In al l of these analytical approaches, evidence indicated the presence of p ositive associations between heterozygosity at enzyme loci and biomass production. The theoretical implications of these results are discuss ed in the specific context of this study.