Plant & Animal Genome VI Conference

P96

GENETIC DIVERSITY IN AZALEA (R. simsii) GERMPLASM BY MEANS OF AFLP

1. Department for plant genetics and breeding, Centre for Agricultural Research-Gent (CLO)., Burg. Van Gansberghelaan 109, B-9820 Merelbeke, Belgium.
2. Department of Plant Production, University of Gent, Coupure Links 653, B-9000 Gent, Belgium.

The current assortment of Belgian pot azalea (Rhododendron simsii hybrids) has been created from a relatively narrow basis of collectors material. R. simsii, the main ancestor, originates from hilly areas in China (Chang Jiang valley), Thailand, Laos and Burma. However, several other species from the Tsususi 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 Rhododendron populations in mountain areas with an altitude ranging from 250 to 3500 m were obtained. The majority belongs to the Tsususi subgenus; 8 are R. simsii. Ten plants per population were compared to the breeders pot azalea genepool. AFLP was performed using fluorescent fragment detection on an ABI Prism 377 DNA Sequencer with three EcoRI-MseI PC (6 selective bases). Genetic diversity was studied by comparison of the marker frequencies (Euclidean Distance) and by Analysis of Molecular Variance. Small differences within populations were observed. However, large variation occurred within the R. simsii species and between the different species from the Tsususi subgenus. However, a grouping of accessions belonging to the same geographic region was found. The Belgian pot azalea genepool was clearly distinct from the Chinese accessions. However, on dendrograms it was more closely clustered to R. simsii and R. mucronatum than to species that are considered to be less related.