|Suh, Jeung Keun -|
|Hetterscheid, Mark -|
|Lee, Ae Kyung -|
|Hong, Jeong -|
Submitted to: Genetic Resources and Crop Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 20, 2010
Publication Date: February 10, 2011
Citation: Suh, J., Hetterscheid, M., Lee, A., Hong, J., Roh, M.S. 2011. Identification and evaluation of Forsythia germplasm using molecular markers. Genetic Resources and Crop Evolution. DOI 10.1077/210722-010-9656-3. Interpretive Summary: Forsythia is an ornamental landscape shrub that flowers early in spring. Ten to 13 species are native to China, Korea, and Japan; one species, F. europaea is native to Albania and Yugoslavia. Forsythia ×intermedia hybrids were formed from natural hybridization between F. suspensa and F. viridissima without human involvement. However, chloroplast DNA studies did not support F. suspensa (Thunb.) Vahl . and F. viridissima Lindl as the parental species. Forsythia koreana was considered a potential parent as well. Therefore, this study evaluated the molecular genetic relationships of F. ×intermedia hybrids, cultivars, and several Forsythia species native to northeastern China, Korea, and Japan with randomly amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) analysis. The placement of F. ×intermedia cultivars with F. suspensa in the AFLP dendrogram was comparable to placement in the RAPD dendrogram. RAPD and AFLP results clearly separated most F. ×intermedia cultivars from F. ovata-derived cultivars. Although the data support that F. suspensa is one of its parental taxa, the genetic diversity of F. suspensa and F. viridissima should be investigated to verify that these two species are truly parental taxa for F. ×intermedia.
Technical Abstract: This study identified Forsythia germplasm and evaluated the genetic relationships of F. ×intermedia hybrids, cultivars and their putative parental species. Leaf samples of F. ×intermedia cultivars and species, such as F. koreana and F. suspensa, were collected in the Netherlands, Korea, and USA. Total genomic DNA was extracted and evaluated by randomly amplified polymorphic DNA (RAPD) and amplified fragment length polymorphism (AFLP) analysis. Dendrograms were constructed using the neighbor-joining (NJ) tree-building method applying the interior branch (IB) test or analyzed by structure. In the dendrogram generated by RAPD markers, two major clusters were observed. One cluster contained most of the F. ×intermedia cultivars, F. suspensa, and F. koreana. The other cluster included F. europaea, F. ovata, F. densiflora, F. mandshurica, F. japonica, F. viridissima, and cultivars derived from F. ovata. The placement of F. ×intermedia cultivars with F. suspensa was similar in the AFLP dendrogram. The RAPD and AFLP results clearly separated most F. ×intermedia cultivars from F. ovata-derived cultivars. The genetic diversity of F. suspensa and F. viridissima should be investigated to verify whether these two species are truly parental taxa for F. ×intermedia. Placement of F. viridissima, F. ovata, and F. japonica in different sub-clusters requires further investigation regarding the genetic diversity of these taxa, and their close relationship with F. koreana, F. mandshurica, and F. saxatalis.