MECHANISM OF THE APPEARANCE OF ALBINO SEEDLINGS IN REMOTE CROSSINGS IN AZALEAS

许多育种家试图将日本杜鹃花与几种常绿杜鹃花进行多次杂交，以获得黄花常绿杜鹃花。但几乎所有的幼苗都是白化的，在开花时从未生长。1996年，我们成功地通过三道杂交获得了常绿杜鹃花的绿色幼苗。我们报道了常绿物种的质体体与日本稻的核基因组不相容是白化植物出现频率高的原因，而绿色植物只有在质体体来源于日本稻时才会出现。因此，为了成功获得绿色植株的频率，应在这类杂交中使用日本花作为种子亲本。但是由于没有设置太空舱，这样的穿越是不成功的。在这项研究中，我们获得了一株绿色幼苗，这是由kiusianum与japonicum单次杂交获得的。该幼苗为三倍体，具有常绿树种的质体。在以前的报道中，我们研究了白化幼苗的出现似乎源于ptDNA与核DNA的不相容。然而，从这些发现来看，具有核基因组的三倍体幼苗，来自r.k usianum （2x）和来自r.j japonicum (x)的三倍体幼苗表现出绿色的叶片，而不表现出不亲和性。

Many breeders attempted that many crossing between Rhododendron Japonicum and several evergreen azaleas for the obtainment of yellow-flowered evergreen azaleas. But almost all seedlings were albino and have never grown at anthesis.In 1996, we succeeded to obtain the green seedlings by three way crossings among R.japonicum and evergreen azaleas. We reported that high frequency of albino plant appearance was caused by incompatibility between plastome from evergreen species and nuclear genome from R.japonicum, and that green plants appeared only when their plastomes were originated from R.japonicum. Therefore, to succeed the frequency of green plant obtainment, R.japonicum should be used as seed parents in such crosses. But such crossings are unsuccessful because of failure to set capsules. IN this study, we obtained a green seedling from the single crossing between R. kiusianum x R. japonicum. This seedling was triploid and have plastome from evergreen species. In the previous reports, we investigated that the appearance of albino seedlings seem to originated in the incompatibility between ptDNA and nuclear DNA. From these findings, however, it seems that the triploid seedlings that have nuclear genome originated from R. kiusianum (2x) and originated from R. japonicum (x) show green leaves and not show the incompatibility.