Obtainment and confirmation of intergeneric hybrids between marguerite (Argyranthemum frutescens (L.) Sch.Bip.) and two Rhodanthemum species (R. hosmariense (Ball) B. H. Wilcox, K. Bremer & Humphries and R. catananche (Ball) B. H. Wilcox, K. Bremer & Humphries).

Argyranthemum frutescens (L.) Sch.Bip. and Rhodanthemum gayanum (Coss. & Durieu) B. H. Wilcox, K. Bremer & Humphries are capable of hybridization. To expand flower color variation in this intergeneric hybrid group, we performed crosses using A. frutescens as the seed parent and R. hosmariense (Ball) B. H. Wilcox, K. Bremer & Humphries, R. catananche (Ball) B. H. Wilcox, K. Bremer & Humphries as the pollen parent. One plantlet was obtained from each cross between the white to pale pink-flowered A. frutescens and white-flowered R. hosmariense, and from a cross between the pink-flowered A. frutescens and cream to pale yellow-flowered R. catananche, via ovule culture. The cross with R. hosmariense produced an individual with white to pale pink ray florets, and the cross with R. catananche produced an individual with red ray florets. The flower and leaf shape of the progenies was intermediate between the parents, and other morphological traits were also characterized in the same manner. Morphological observations and a cleaved amplified polymorphic sequence marker-based determination, using the internal transcribed spacer region as a target for amplification and the restriction enzyme Afl II, revealed that both individuals are hybrids between A. frutescens and R. hosmariense, R. catananche. To the best of our knowledge, this is the first study to report that crossbreeding between A. frutescens (seed parent) and R. hosmariense, R. catananche (pollen parent) is possible. Moreover, further development of Argyranthemum breeding, especially that of a series of hybrid cultivars with different flower colors, is expected.