Inheritance of Morphological Characters and RAPD Markers in Intersubgeneric Hybrids of Azalea, (Rhododendron kiusianum Makino*R. indicum (L.) Sweet)*R. japonicum (A. Gray) Suringer f. flavum Nakai.

Abstract

The inheritance of morphological characters and RAPD (random amplified polymorphic DNA) markers among the intersubgeneric hybrids of (Rhododendron kiusianum Makino × R. indicum (L.) Sweet) ×R. japonicum (A. Gray) Suringer f. flavum Nakai was investigated to clarify the usefulness of RAPD markers in the breeding program of yellowflowered evergreen azalea (Akabane, 1993).Tree forms of the hybrids were similar to R. japonicum f. flavum. Leaf morphology of the hybrids was intermediate to that of the parents. Microscopic observation of foliar trichomes revealed that all the hybrids had long hairs similar to those of R. japonicum f. flavum. The short hair trait of R. japonicum f. flavum. was observed in some hybrids. The degree of defoliation in winter varied among the hybrids.Seven out of 16 primers, generated a total of 28 RAPD bands. The hybrids and their parents could be distinguished by band patterns. Inheritance of RAPD bands was confirmed by Southern hybridization.Variations in morphology and polymorphisms of RAPD pattern among the hybrids were attributed to the heterozygosity and the phylogenetic distance between the parental species. The hybrids that had more paternal RAPD bands tended to exhibit more patrilineal morphological characters. This suggests that some RAPD markers and morphological characters may be linked.