AFLP assessment of genetic variability in old vs. new London plane trees (Platanus x acerfolia)

London plane tree (Platanus X acerfolia) is a popular street tree and is a hybrid between the American sycamore and the Oriental plane tree. Using AFLP markers, genetic diversity and phenetic relationships were estimated in 38 London plane tree samples from Schenley Park, Pittsburgh, PA, USA, and from several nurseries. This investigation was intiated in order to manage, more effectively, the replanting of London plane trees in an existing (approx. 100 year-old) stand of approx. 100 trees. Four selective primer combinations generated a total of 492 amplification products, and 381 polymorphic markers were detected. Polymorphism ranged from 60 - 82%, with an average of 77%. A phenetic tree was constructed using Nei and Li's coefficient of similarity with UPGMA. Other clustering algorithms were examined and all gave similar co-phenetic correlation values. The phenetic tree separated the nursery trees from the Schenley Park samples. Bootstrap analyses were completed, and the values gave strong support for this clade. We investigated the different propagating techniques applied between these samples. The Schenley Park plants had been grown from seed or seedlings, while the nursery plants were clonally propagated, which correlated with the observed differences in similarity coefficients. The level of genetic variability detected by AFLP analysis within these London plane tree samples suggested that this is a reliable, efficient, and effective marker system that can be used for better management of rural tree plantings.