Submitted to: Acta Horticulturae
Publication Type: Proceedings
Publication Acceptance Date: 2/26/2015
Publication Date: 6/28/2015
Citation: Rinehart, T.A., Pounders Jr, C.T., Wang, X., Pooler, M.R. 2015. SSRs are useful to assess genetic diversity among Lagerstroemia species. Acta Horticulture Proceedings. (ISHS) 1087:49-58.
Interpretive Summary: The crapemyrtle is a popular ornamental shrub or tree with hundreds of named cultivars with diverse combinations of flower color, growth habit, and bark characteristics. Until the 1970s, Lagerstroemia indica was the most common ornamental species in the U.S. Since then, breeders have incorporated genetic material from L. fauriei, L. speciosa, L. limii, and L. subcostata. Given the large number of species available, other species may be more suitable for creating wide hybrids in crapemyrtle breeding programs. Information on genetic relatedness can provide insight into which crosses are more likely to produce fertile offspring for continued breeding.
Technical Abstract: The most recent and widely accepted taxonomic revision of Lagerstroemia occurred in 1969 and is based on morphological characters. As described, the genus is split into three sections and includes more than 50 species, several of which are grown for lumber in Asia and the Philippines. Three species, L. indica, L. fauriei, and L. speciosa, are cultivated as ornamental trees. Crapemyrtle breeding in the United States began with L. indica but is now dominated by interspecific hybrids between L. indica and L. fauriei, mostly to improve resistance to powdery mildew. Recently interspecific hybrids have been created between L. indica and L. speciosa to increase flower size. Resulting progeny were sterile, suggesting a need to find bridging species or use embryo rescue. While most Lagerstroemia species lack the hardiness to be grown as ornamentals in colder temperate zones, there is potential for interspecific combinations to improve growth habit, disease resistance, and flower size. We used SSRs to assess genetic diversity and relatedness, and predict wide hybridization success.