This study was carried out to compare the survival and mutation rates and mutation spectrum by gamma-irradiation on rooted and unrooted cuttings of three spray type (‘Lovelydia’, ‘Yellowbabe’, and ‘Haetsal’) and two standard type (‘Vital’ and ‘Aqua’) cultivars in roses. Two groups, rooted and unrooted cuttings were gamma-irradiated at 70Gy for 24 hours. The irradiated rooted and unrooted cuttings were planted in a greenhouse, and survival, mutation rates and mutation spectrum were investigated 30 weeks after planting, respectively. As a result, survival and mutation rates ofgamma-ray irradiated plants were 16.4%~50.8% and 0~5.1% for unrooted cuttings, and 39.4%~55.1% and 0.7%~7.4% for rooted cuttings, respectively. In conclusion, both survival and mutation rates were a little higher on rooted cuttings than on unrooted cuttings. However, when only survived plants after gamma-ray irradiation were considered, mutation rates were 0~10% and 1.8%~14.1% for unrooted cuttings and rooted cuttings, respectively, showing no significant difference. In addition, diverse variations on color and number of petals or shape of flowers were detected both in plants from rooted and unrooted cuttings, which indicated that there was no significant difference in mutation spectrum between two groups.

Rose (Rosa Hybrida Hort.) are of a high symbolic value and a great cultural importance in different societies. They are widely used as garden ornamental plants and as cut flowers. For the induction of mutation, gamma-rays are widely used as a mutagen. This study was carried out to establish a system for mutation breeding by irradiation of gamma-ray in rose. The rooted cuttings of five cultivar roses (Lovelydia, Vital, Aqua, Yellowbabe and Haetsal) are grown by in a greenhouse. They were two difference treatment (Before rooting gamma-ray irradiation, After rooting gamma-ray irradiation) were exposed to dose of 70 Gy using a 60Co gamma-irradiator (150 TBq of capacity ; ACEL, Canada) at the Korea Atomic Energy Research Institute. The irradiated plants were planted in a greenhouse, and investigated survival rate, mutation rate, flower buds number, and shoot length were planted after 80days. The two treatments of and growth characters was significantly reduced to 20% to 40% compared with the control. In addition, survival rate and mutation rate were ‘after rooting γ-ray irradiation (37.4~67.3% and 0.5~5.6%)’ higher than ‘before rooting γ-ray irradiation (18.3~50.8% and 0.3~3.4%)’. Mutation types were solid type, chimeric and mosaic petal mutants with various colors were induced from five rose. These results indicate that efficiency of mutation induction in rose by gamma-ray irradiation on petal colors and petal shapes in two difference treatment with rooted cutting system.