Population Structures in Rhododendron metternichii var. hondoense Assessed with Microsatellites and their Implication for Conservation

Rhododendron metternichii var. hondoense is its great morphological variation. Individuals may have only one erect stem or may have multiple creeping stems, implying that some of them recruit vegetatively. Aims of this study are to ascertain whether a population of R. metternichii var. hondoense consists of clonal plants, and to evaluate relative importance of sexual and asexual recruitments in regard to its conservation. Six microsatellite loci were analyzed in two populations growing in different habitats. One was in a mesic valley consisting of many sprouting and creeping individuals with few seedlings, and the other on a mountain ridge consisting of single stem individuals with many seedlings. Sufficient polymorphisms were found to be present even in the mesic valley population that consisted of many sprouting and creeping stems, indicating that in the past the population was maintained by both sexual and asexual reproduction. The scarcity 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 management systems. Required conservation measures are discussed based on these results. Received 8 July 1999/ Accepted in revised form 26 August 1999