A Dwarf Type New Rose of Sharon Variety, “Ggoma” Developed by a Mutation Breeding

‘Ggoma’ is a new Hibiscus variety released by a mutation breeding using a gamma ray irradiation at the Korea Atomic Energy Research Institute (KAERI). One hundred seeds of the original native variety, ‘Hongdansim 2’, were collected from around a 35 year old plant, grown in a breeding field in Namyangju, Gyeonggi Province. The seeds were irradiated with a 100 Gy gamma ray from a ⁶⁰Co source at KAERI in 1991 (Fig. 1). The original variety, ‘Hongdansim 2’ within the I-b category represents a single flower, with an intermediate petal width and a light purple color with a red eye in the center of its flower. The irradiated seeds were sown in the Namyangju breeding field in April 1992. One plant was selected as a potential mutant ‘Hongdansim 2-10-11 from thirty-two out of the irradiated 100 seeds which survived in 1994. The mutant was propagated by a cutting method and it’s phenotypic traits were investigated from 1997 to 2001, and then we tentatively named the final selected-mutant ‘Weonnong 4’. Most of the leaf traits except for the base angle of the mutant were much smaller than those of the original variety (Table 1). The flower color was light purple in the RHS 77C code based on the color chart prepared by The Royal Horticultural Society, London, which was identical to the flower color of the original variety. The flower type of the selected mutant was an I-a type, which was different from the original variety (I-b). Flower width and length, petal width, and the red-eye length of the mutant were much smaller than those of the original variety (Table 2). Also the plant height of the selected 8 year old mutant was about 1 m and available as a bonsai or pot culture. The name of the new variety, ‘Ggoma’ reflects its dwarf type (Fig. 2).