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

许多育种家试图在杜鹃花与几种万年青杜鹃花之间进行多次杂交，以获得黄花万年青杜鹃花。1996年，我们用杜鹃花与万年青杜鹃花进行三交，获得了绿色苗。我们报道了高频率的白化病植株的出现是由于来自万年青物种的质体与来自日本杜鹃的核基因组之间的不相容性造成的，而绿色植株的出现仅在其质体起源于日本杜鹃时。因此，为了获得较高的绿色植株频率，在杂交育种中应选用日本红豆作为亲本。但由于未能设置胶囊，这种穿越是不成功的。本研究以红毛菊与红毛菊单交获得了绿色苗。黄木山茱萸此苗为三倍体，具有万年青植物的质体。在以前的研究中，我们发现白化病苗的出现可能是由于ptDNA与核DNA不相容所致。然而，从这些发现来看，具有核基因组的三倍体幼苗似乎起源于R。kiusianum（2x），起源于R. japonicum（x）表现为绿色叶，不表现不亲和性。

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.