Abstract: Over the past ten years, 59 pair different combination of the genus Rhododendron were studied in Kunming Botanical Garden. The result shows that (1) diploid species x diploid species shows good affinity, the rate of fruit is 37.5%--100%, (2) it has not affinity if diploid species x polyploid species, (3) it shows good affinity if the parents from same subgenus and same group even the parents belong to different subsection, (4) they are markedly sterile if the parents belong to different subgenus.

Key words: Rododendron