Studies on the breeding of yellow-flowered evergreen azaleas through three way crossings.

到目前为止，为了获得黄花常绿杜鹃花，日本杜鹃与几种常绿杜鹃进行了大量的杂交。1996年，我们进行了日本杜鹃花与常绿杜鹃花的单向杂交和三向杂交试验，考察了它们的种皮结实率、胚珠数、叶色以及幼苗的杂交性。1997年，我们利用聚合酶链式反应-限制性片段长度多态性技术研究了叶色与ptDNA的关系，并对白化苗的形成因素进行了探讨。常绿杜鹃花与日本红豆杉杂交获得的白化苗的ptDNA来自种本(母本遗传)，而绿苗的ptDNA来自花粉亲本(父本遗传)。一般来说，杜鹃花的ptDNA通常是从种子亲本那里遗传来的，这些结果表明，白化苗的出现与杜鹃花种间杂交中ptDNA的遗传有关。此外。白化苗的出现可能源于ptDNA与核DNA的不亲和性。

Until now, a lot of crossings between Rhododendron japonicum and several evergreen azaleas were done for the obtainment of yellow-flowered evergreen azaleas. But almost all seedlings were albino and have never grown at anthesis.In 1996, we tried single and three way crossings between R.japonicum and evergreen azaleas and investigated the rate of capsule set, number of ovules, leaf color and the hybridity of the seedlings. The green seedlings were obtained in the three way crossings whereas those were not in the single crossings.In 1997, we investigated the relationship between leaf color and ptDNA by PCR-RFLP and discussed about the factor of the appearance of albino seedlings.The ptDNA of albino seedlings obtained from the crossings between Fl of evergreen azaleas and R.japonicum were originated in seed parents (maternal inheritance) whereas the ptDNA of the green seedlings were originated from pollen parents (paternal inheritance). In general, ptDNA of azaleas were usually inherited from seed parents.From these results, it was suggested that the appearance of albino seedlings related with the inheritance of ptDNA in the interspecific crossings in azaleas. In addition. the appearance of albino seedlings seem to be originated in the incompatibility between ptDNA and nuclear DNA.