GENOTYPIC VARIATION IN POLYGONUM-PENSYLVANICUM - NUTRIENT EFFECTS ON PLANT-GROWTH AND APHID INFESTATION

Variation in the performance of 20 genotypes of Polygonum pensylvanicu m under two nutrient treatments was studied in a garden experiment. Nu trient fertilization enhanced vegetative biomass and fruit biomass pro duction, but did not result in significant genotype-environment intera ctions, suggesting that nutrient variation of the range used in the ex periment has little potential as a microevolutionary factor in this sp ecies. Leaf nitrogen concentration was not affected by a nutrient puls e. The degree of transient aphid infestation that occurred during the experiment had a weak positive correlation with final reproductive bio mass of plants. Mean density of aphids per leaf was negatively correla ted with percent leaf nitrogen and was not affected by genotypic ident ity of host plants.