Development of Sequence Tagged Microsatellite Site (STMS) markers in Azalea

A genomic library was constructed from DNA of two azalea genotypes: a Belgian pot azalea R. simsii hybrid Mevr. Van Belle and a Chinese R. simsii from Daoxian. An enrichment of microsatellite containing sequences was performed as in Van de Wiel et al. (1999). Fragments were sequenced and primers were designed that allow the amplification of the microsatellite repeat. About 220 microsatellite containing clones were selected from the enrichment procedure. Mainly dinucleotide repeats and some trinucleotide repeats were found. The selected primers were tested in a small set of reference varieties to check their value (specificity and polymorphic rate) and to set up the PCR-conditions. Five primer pairs have been tested, two of them gave a specific and polymorphic pattern. They were further screened by radioactive PCR on a selection of 5 plants from the azalea breeders gene pool which included the two genotypes used library construction. These 2 STMS markers uniquely identified the 5 plants

Development of Sequence Tagged Microsatellite Site (STMS) markers in Azalea

A genomic library was constructed from DNA of two azalea genotypes: a Belgian pot azalea R. simsii hybrid Mevr. Van Belle and a Chinese R. simsii from Daoxian. An enrichment of microsatellite containing sequences was performed as in Van de Wiel et al. (1999). Fragments were sequenced and primers were designed that allow the amplification of the microsatellite repeat. About 220 microsatellite containing clones were selected from the enrichment procedure. Mainly dinucleotide repeats and some trinucleotide repeats were found. The selected primers were tested in a small set of reference varieties to check their value (specificity and polymorphic rate) and to set up the PCR-conditions. Five primer pairs have been tested, two of them gave a specific and polymorphic pattern. They were further screened by radioactive PCR on a selection of 5 plants from the azalea breeders gene pool which included the two genotypes used library construction. These 2 STMS markers uniquely identified the 5 plants

The use of fluorescent AFLP to assess genetic conformity of a breeders collection of R-simsii hybrids

In the present study, fluorescent AFLP was used to assess the genetic conformity in a breeders gene pool of evergreen azaleas. Aims were twofold: 1.) evaluate the correspondence between classifications based on pedigree data and on AFLP marker data for a well characterised breeding gene pool of pot azaleas, and 2.) assess the genetic relationships between pot azaleas, Japanese azaleas and their supposed ancestor species from the Rhododendron subgenus Tsutsusi

Azalea (Rhododendron simsii hybrids) germplasm from China assessed by means of fluorescent AFLP

The current assortment of pot azalea (Rhododendron simsii hybrids) has been created from a relatively narrow basis of collectors material (botanical gardens, private collections) brought from the far east. R. simsii, the main ancestor, originates from hilly areas in China (Chang Jiang valley), Thailand, Laos and Burma. However, several other species from the Tsutsusi subgenus, from South-Asia and Japan, might have contributed: e.g. R. indicum, R. mucronatum and R. scabrum. From the Kunming Institute of Botany (China) 33 seed lots from natural populations in mountain area's with an altitude ranging from 250 to 3500 In were obtained. The majority of these Rhododendron species belong to the Tsutsusi subgenus; 8 are R. simsii. per population 10 plants were analysed by AFLP using 3 primer combinations. They were compared to the breeders pot azalea genepool (70 plants, some with common pedigree and bud sports). AFLP was performed using the commercially available kit (ABI-Perkin-Elmer) for fluorescent fragment detection on an ABI Prism 377 DNA Sequencer. The genetic diversity of the different gene pools was analysed by comparison of the marker frequencies, by calculating similarity indices, by multivariate analysis and AMOVA. Small differences within populations were observed. Large variation was observed within the R. simsii species and between the different species from the Tsutsusi subgenus. The pot azalea genepool was clearly distinguishable from the Chinese accessions. On dendrograms it was more closely clustered to R, simsii and X. mucronatum than to less related species