Genetic control of Populus tremuloides sensitivity to metabolites of Hypoxylon mammatum

Abstract

Tissue culture plantlets derived from the vegetative buds of six aspen trees and from the seeds of controlled pollinations of these trees were bioassayed with culture filtrates from three isolates of Hypoxylon mammatum. Analysis of variance of parent and progeny bioassay responses revealed significant main effects and insignificant interaction, which suggests that metabolite sensitivity is a horizontally controlled trait. However, in certain crosses progeny response differed markedly from that of either parent. In these cases progeny were either far more or far less sensitive than the parents. This dramatic switching of sensitivity to the metabolites suggests that this trait is conditioned by a small number of genes. Key words: Populus tremuloides, Hypoxylon mammatum, phytotoxin.