INTERSUBGENERIC HYBRIDIZATION OF BELGIAN POT AZALEAS (RHODODENDRON SIMSII) WITH TROPICAL VIREYA GENOTYPES
Belgian pot azaleas are a Rhododendron hybrid group belonging to the Tsutsusi subgenus. Intersubgeneric crosses with genotypes from other subgenera having interesting traits such as new flower colours, forms or altered growth habits are mostly unsuccessful. The aim of the current research is to evaluate the possible use of Vireya genotypes for intersubgeneric sexual hybridization with Belgian pot azaleas. To this end, 5 Vireya genotypes, R. laetum, R. Sunny, R. Silver Thimbles, R. Jazz Band and R. Our Marcia were used as seed parents in crosses with 8 pot azalea cultivars. Altogether, 160 flowers were pollinated. After 2 months, the number of non-aborted fruits was counted and the immature seeds were dissected and sown in vitro on an embryo rescue medium. All Vireya genotypes set fruit; the success rate varied between 41% (R. Silver Thimbles) and 100% (R. laetum). The final efficiency varied between 0.2 hybrid plants / pollinated flower for the seed parent R. Jazz Band and 6 for R. Sunny. For R. laetum, 1.4 plants were obtained per pollinated flower; for R. Silver Thimbles and R. Our Marcia this proportion was 0.22 and 0.44, respectively. Viable hybrid plants were obtained from each Vireya seed parent. Many of the hybrids displayed an intermediate plant and flower morphology. Nevertheless, none of the hybrids produced fertile pollen. Our results are in accordance with earlier findings and indicate a significant potential for Vireya types for the induction of intersub-generic F1 hybrids.
Eeckhaut, T., Calsyn, E. and Van Huylenbroeck, J. (2013). INTERSUBGENERIC HYBRIDIZATION OF BELGIAN POT AZALEAS (RHODODENDRON SIMSII) WITH TROPICAL VIREYA GENOTYPES. Acta Hortic. 990, 259-263
embryo rescue, Ericaceae, in vitro, ornamental, Tsutsusi