Population structures in Rhododendron metternichii var. hondoense assessedwith microsatellites and their implication for conservation

An ecological feature of Rhododendron metternichii var. hondoense is its gr eat morphological variation. Individuals may have only one erect stem or ma y have multiple creeping stems, implying that some of them recruit vegetati vely. Aims of this study are to ascertain whether a population of R. metter nichii var. hondoense consists of clonal plants, and to evaluate relative i mportance of sexual and asexual recruitments in regard to its conservation. Six microsatellite loci were analyzed in two populations growing in differ ent habitats. One was in a mesic valley consisting of many sprouting and cr eeping individuals with few seedlings, and the other on a mountain ridge co nsisting of single stem individuals with many seedlings. Sufficient polymor phisms were found to be present even in the mesic valley population that co nsisted of many sprouting and creeping stems, indicating that in the past t he population was maintained by both sexual and asexual reproduction. The s carcity of seedlings at the mesic valley was due to dense litter cover and low bryophyte mat cover which may be caused by changes in traditional manag ement systems. Required conservation measures are discussed based on these results.