Genetic Variation in the Wood of Fraxinus Americana

Joseph E. Armstrong, David T. Funk


The wood structure of white ash seedlings representing seven populations ranging from New Brunswick to Arkansas was compared. All the seedlings were raised in a nursery in southern Illinois to reduce environmental sources of variation. Any variation observed was attributed to ecotypic adaptation to the environment at the seed source. The genetic variation in wood cell sizes was separated into two components, one related to the geographic origin of the seed source, and the other related to the ploidy level of the tree. Diploid trees from the southernmost seed source had slightly longer vessel elements and fibers than diploid trees from northern seed sources. The longest-celled trees studied were those that were found to have polyploid genomes. There was no correlation between the rate of cambial divisions and cambial derivative lengths. Variation related to ploidy and geographic source may prove useful in a tree improvement program designed to increase fiber length.


Polyploidy;wood anatomy;genetic variation;white ash;fiber length

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