INTRODUCTION
Caryopteris incana (Thunb.) Miq. is a perennial plant or shrub natural to China, Taiwan, Korean Peninsula, and Japan.
Plant height may exceed 1 m from 30 cm, stand upright, and branch.
Opposite leaves egg-sharped have strongly aromatic with coarsely serrate, and their surface is a grey-green color [1].
Cymes extend from the axillae above the stem with blue-violet, fragrant flowers.
The inflorescence has a ring-like flower cluster on the stem and blooms from the lower part to the upper part.
It is a short-day plant that blooms from September to October, and the upper leaves die after 1 ~ 2 months of blooming.
In early winter, a few leaflets remain in a rosette and overwinter.
It is used for horticultural purposes, as well as for flower arrangement and garden planting.
In particular, many of cultivar group of Caryopteris ×clandonensis A. Simmonds by mating C. incana (seed parent) with C . mongholica Bunge.(pollen parent) is used as a garden plant or cut flower mainly in Europe and the United States because it is a hardy horticultural plant [2].
However, cultivars or C. incana in circulation have only 3 color of flowers is blue-violet, white (C . incana f.candida C.K. Schneid.), pink (C . incana f.rosea Sugim.), few cultivars distinguished in the form except the flower color are produced.
Therefore, it is necessary to obtain phenotypic information in wild types as a breeding material for diversifying horticultural cultivars ofC. incana, C.×clandonensis .
Outside of these horticultural uses, C. incana contains several phenylpropanoid glycosides, including the proprietary incanoside (Gao and Han, 1997; Gao et al ., 1999, 2000; Li and Wang, 2004; Zhaoet al ., 2009), which is used in China as folk medicine with medicinal properties against pertussis, menstrual irregularities, eczema, and rheumatic pain [1,3].
In addition, GC/MS analysis of volatile compounds showed that fumigants and essential oils from C. incana exerts potent insecticidal effects against the weevil, Euscepes postfasciatus, a stored grain pest in Poaceae [4].
In addition to the horticultural ornamental value, C. incana has the value as a functional plant.
C. incana is considered to be one of the continental plants that remain on the islands of western Kyushu and western mainland Japan (Ito, 1997), and its natural environment in Japan is limited to western Kyushu [5,6].
C. incana , which grows mainly in exposed rocky areas, shows lithophytic features, such as in soil and in crevices where organic matter accumulates. And is sometimes observed in the same assemblage asSelaginella tamariscina (P. Beauv.) Spr. [6].
Based on these natural environments, it is considered that each natural population of C. incana is distributed locally (not continuously), and that it exists in multiple local populations in the same region.
In addition, the number of indigenous populations has been declining due to destruction of natural environments, mainly due to land reclamation, road maintenance, trampling, etc., and was listed in the Red Data Book in 2000 as Endangered Class II (VU) [7].
An investigation of the habitat of C. incana in Japan was reported by Itow and Kawasato (1988) in 1988 [6].
Since the distribution of C. incana had not been investigated since this survey, we conducted a habitat survey in western Kyushu, Japan [8,9].
We identified 72 populations on Tsushima, Nagasaki Prefecture, 16 populations on the mainland of Nagasaki, 16 populations on the Goto Islands, and 109 populations on Koshikijima Islands, Kagoshima Prefecture (Fig. 1).
Among these areas, we confirmed that the indigenous population tended to decrease in the mainland of Nagasaki.
In addition, DNA was extracted from the seedling of the seeds collected from each natural population, and the chloroplast DNA was sequenced.
As a result, interpopulation variation was identified in 6 regions of chloroplast DNA, and a total of 22 haplotypes were identified, including 6 types in Tsushima, 6 types in the Nagasaki mainland, 9 types in the Goto Islands, and 3 types in the Koshikijima Islands.
Phylogenetic analysis revealed multiple sequence variation between these haplotypes and populations distributed in the Tsushima, Nagasaki mainland, and the Goto Islands, the Koshikijima Islands, and parts of Nagasaki mainland, and they were classified into two groups, suggesting early disjunction between these regions.
We also identified common haplotypes in natural populations in the northwestern part of Nagasaki mainland and the Koshikijima Islands.
Base on these results, we clarified the genetic structure and genetic diversity among wild populations of giant reed in western Kyushu based on chloroplast DNA.
On the other hand, the phenotypic diversity of the C. incana has not been studied.
As C. incana is characterized as a chasmophyte plant, it has a localized assemblage of individuals that can be recognized as a population and grows in a spatially isolated state.
Therefore, there is a possibility that the phenotype variation adapted to the natural environment occurs in each population.
The objective of this study was to investigate phenotypic variation in each natural population by growth survey and to evaluate its association with geographical structure.
These results suggest that the phenotypic diversity of the indigenous population in western Kyushu and comparison with the genetic structure in chloroplast DNA may clarify the relationship between phenotypic variation and genetic variation.
Information on these phenotypes may contribute to the utilization of plant resources such as breeding materials and the planning of conservation programs as endangered species.