Satoshi Yamaguchi

Laboratory of Ornamental Plant Science

National Institute of Vegetables,Ornamental Crops and Tea

Ministry of@Agriculture, Forestry and Fisheries Mii-1923,Kurume City,Fukuoka Pref.,#830.JAPAN

Historical background of the Kurume azaIea

Evergreen azaleas are aboundant in the East Asia,especially in japan. In the spring,we can see various beautiful azaleas at around our country.Several azalea species have been domesticated and appear in our public and hone gardens. But the way to diversify as the important landscaping plants of them has been still in the mistiness. The@modern Kurume azalea.for example, have an obscure story of its origin and@sophistication. Many scientist both in horticultual and botanic fields and argued on its ancestor species.

The name of Kurume Azalea is in recent appearance in our literatures later than in 1918. Before that name, those plants were under the names, such as Kirishima. Kirishima tsutsuji and Ko-Kirishima. The most prior name adopted was Kirishima. That is the name of its home locality, Mt.Kirishima,Kagoshima pref. in the Southern part of Kyushu Isl .

2.Biosystematic studies

In the days, Dr.Sakata, Kagoshima Univercity, prevailed the chenical analysis of flower pigment in the evergreen azalea species in Kyushu Isl. He found the more intimate resembrance in the pigment constitution of Kurume azalea and the wild azalea population in the Mt.Kirishima than in that of Kurume azalea and R.Satatase. His findings are summarized as follows.

R.Kiusianum Delphinidin(D) Mctliylated(M) H.Sataeuse C and D non-M Kurume Azalea C and Mt.Kirishima Population C and D M and non-M

Accordiag to his results, R.sataense lacks the methyIated fIavonoI, which is present in the Kurume azalea and the wild population of Mt.Kirishima.

However , my study in the stomata distribution of the Ieaf among evergreen azalea species and cultivars tells a different story. R.Kiusianum has small stomata and high density on the leaf. R.Kaempferi has large stmata and low density. The plants of the population of Mt. Kirishima, Kurume azalea and even R. sataense show wide variation in the stmata size and density, intermediate between those of both two species.

Then, I conclude thus; The population of Mt.Kirishima, R.sataense and Kurume AzaIea be Iong to the same bIood famiIy, due to the interspececific hybridization between R. Kaempferi and R. kiusianum. And , the differences in the presence of methylated flavonoI , anthocyanidin types , fIower color , and leaf characters between above mentioned species and cultivars, are due to natural selection undertaken at each home habitats@with different environments and pollinators.