Genotypic variation in Polygonum pensylvanicum: nutrient effects on plant growth and aphid infestation

Variation in the performance of 20 genotypes of Polygonurn pensylvanicum under two nutrient treatments was studied in a garden experiment. Nutrient fertilization enhanced vegetative biomass and fruit biomass production, but did not result in significant genotype-environment interactions, suggesting that nutrient variation of the range used in the experiment has little potential as a microevolutionary factor in this species. Leaf nitrogen concentration was not affected by a nutrient pulse. The degree of transient aphid infestation that occurred during the experiment had a weak positive correlation with final reproductive biomass of plants. Mean density of aphids per leaf was negatively correlated with percent leaf nitrogen and was not affected by genotypic identity of host plants.