Roses are one of the most important floricultural crops, and their essential oils have long been used for cosmetics and aromatherapy. We investigated the volatile compound compositions of 12 flower-color mutant variants and their original cultivars. Twelve rose mutant genotypes were developed by treatment with 70 Gy of 60Co gamma irradiation of six commercial rose cultivars. Essential oils from the flowers of the 18 genotypes were analyzed by gas chromatography–mass spectrometry. Seventy-seven volatile compounds were detected, which were categorized into five classes: hydrocarbons, terpenoids, alcohols, esters, and others. Hydrocarbons, alcohols, and esters were major components in all rose flowers. The mutant genotypes CR-S8 and CR-S9 showed higher contents of hydrocarbons than the original cultivar. In addition, CR-S1, CR-S3, and CR-S4 mutant genotypes showed higher ester contents than their original cultivar. Nonacosane, 2-methylhexacosane, and 2-methyltricosane were major volatile compounds among all genotypes. Hierarchical cluster analysis of the rose genotypes gave four groups according to grouping among the 77 volatile compounds. These findings will be useful for the selection of rose genotypes with improved volatile compounds.

Pseudolysimachion nakaianum (Ohwi) T.Yamaz. is an endemic species that is an important species in the forest ecosystems of South Korea. This study aimed to develop an in vitro propagation system for P. nakaianum, to enhance the availability of this rare and endemic plant for commercial horticulture and restoration efforts. We utilized cotyledon explants from in vitro germinated seeds and two types of explants (petiole and leaf) from in vitro seedlings to assess the impact of five different cytokinins on adventitious shoot organogenesis in P. nakaianum. The half-strength Murashige and Skoog (MS) medium, supplemented with 10 µM thidiazuron (TDZ) for both cotyledon and petiole explants, yielded the highest shoot induction rates (61.1 ± 9.6% and 26.7 ± 8.8%, respectively) and the greatest number of shoots (3 ± 0.6 and 4.4 ± 0.5, respectively). Responses from leaf explants were variable, with none showing in vitro regeneration. Successfully acclimatized P. nakaianum plantlets in a greenhouse demonstrated normal growth. This protocol outlines an effective method for the direct in vitro regeneration from cotyledon and petiole explants of P. nakaianum, providing valuable information for the conservation of this species.