A New Rose of Sharon Variety, “Changhae” Developed by A Mutation Breeding

“Changhae” is a new Hibiscus variety developed by a mutation breeding by using a gamma ray irradiation. One hundred seeds of the original variety, “Suminokura”, grown in a breeding field in the Namyangju, Gyeonggi Province were irradiated with a 100 Gy gamma ray from a ⁶⁰Co source at the Korea Atomic Energy Research Institute in 1993 (Fig. 1). The original variety, “Suminokura” belonged to the I-b category represented by a single flower, with an intermediate ratio of petal length/petal width, and a red purple color with a red-eye in the center of it’s flower. The irradiated seeds were sown in an experiment field in Namyangju, in April 1994. Sixty-five out of the 100 seeds survived. Among them, one plant was selected as a promising mutant line with an attractable flower color, “Suminokura S-10-1” in 1996. The propagation of the mutants by means of a cutting and an investigation of it’s characters were conducted during 1997 to 2002, and then the final selected-mutant tentatively was named as “Weonnong 11”. The leaf traits of the mutant were larger than those of the original variety, except for the incision depth and base angle of the leaf (Table 1). The sizes of a flower, the red eyes and the pistils in the mutant were larger than those of the original variety (Table 2). The flower showed a bluish purple color (RHS 77B) based on the color chart prepared by The Royal Horticultural Society, London. Also, the new variety had a flower type, I-a, which was different from the original variety (I-b). The name of the new variety, “Changhae” reflects its bluish flower color and it’s large flower (Fig. 2).