Effects of different plant hormones on callus induction and plant regeneration of miniature roses (Rosa hybrida L.)

Miniature roses (Rosa hybrida L.) are perennial evergreen or deciduous shrubs and a new variety of the rose family. A number of species, hybrids and cultivars of genus Rosa are widely used as garden plants, cut flowers, potted plants and for the perfume industry.1,2 In Europe, potted miniature roses are of great interest and their popularity is increasing in North America as well.3,4 In Denmark, approximately 35 million potted rose plants have been produced annually during the last 5 years.5 Moreover, due to the low maintenance requirement and extended flowering time, it has been proved to be attractive to consumers globally. Although extensive efforts have been made to enhance the quality and production of these plants since 1990s, but still a lot of improvement can be done.6,7 To date, studies on the factors controlling in vitro rooting have been limited to a few species.8 The frequency of establishment of rooted plants in field triasl was low and highly inconsistent.9–11 Callus induction is a powerful tool to regenerate plants. Callus is a disorganized mass of undifferentiated tissue comprised of actively dividing cells. The cells of callus dedifferentiate and thus regain their meristematic properties, including rapid proliferation.12