Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/28/2006
Publication Date: 1/1/2007
Citation: Smith, N., Trigiano, R., Windham, M., Lamour, K., Habera, L., Rinehart, T.A., Xingwang, W. 2007. Aflp markers identify florida cultivars. Journal of American Society for Horticultural Science. Jan 2007, vol. 132, no.1, pp 90-96. Interpretive Summary: Flowering dogwood (Cornus florida L.) is an important tree of forests and urban landscapes in the eastern United States. This native tree blooms early in the spring as new leaves unfold. The inflorescence consists of petal-like subtending bracts of red, pink or white, surrounding a cluster of 20 or more tiny true flowers that are yellow or white (Witte et al. 2000). Dogwood is an attractive tree in all seasons and has become a widely used landscape tree. Although dogwood is a native tree and many wild trees exist, the popularity of this tree has led to the development of many cultivars. New cultivars are developed from mutations or sports of other cultivars or from the selection of wild dogwood trees for various horticultural traits (Witte et al. 2000). Cultivated lines of dogwoods are propagated from axillary buds, which are grafted onto rootstocks that are produced from wild seed collections (Dirr and Hauser 1998). This propagation technique produces cultivars or lines of purportedly identical trees with specific, desirable phenotypic traits. Cultivated selections have been developed for large bracts, double bracts, red, pink or white bracts, variegated leaves, various growth habits and disease resistance. There are currently more than 80 cultivars of flowering dogwood (Witte et al. 2000) and many are described and illustrated in Cappiello and Shadow (2005). Since many cultivars are very similar in appearance, there is a need for a method of identification that is based on genotype rather than phenotype.
Technical Abstract: Flowering dogwood (Cornus florida) is an important tree of forests and urban landscapes in the eastern United States. Amplified fragment length polymorphism (AFLP) markers were generated from genomic DNA of 17 cultivars and lines and four duplicate samples. Cultivar specific markers were identified for all except three cultivars. A dichotomous cultivar identification key was constructed based on AFLP data and cultivar specific peaks were identified. The key was assessed with seven unidentified (unlabeled) dogwood samples and all unknowns except one were identified using the dichotomous key. Two of the unknown samples, ‘Cherokee Chief’ and ‘Cherokee Brave’, were difficult to distinguish using the AFLP markers and the key. However, DNA Amplification Fingerprinting (DAF), a different anonymous DNA fingerprinting technique, resolved the difference between these cultivars. Intracultivar variation, up to 36% dissimilarity, was observed in duplicate samples of the same cultivar, which suggested that some mislabeling of trees had occurred. The cultivar specific AFLP markers can be used in breeding applications, patent protection and in future projects, such as mapping the Cornus genome.