Proc. III IS Rose Research Eds. N. Zieslin & H. Agbaria Acta Hort. 547, ISHS 2001 147 MICROPROPAGATION, PROTOPLAST CULTURE AND ITS IMPLICATIONS IN THE IMPROVEMENT OF SCENTED ROSE Pratap Kumar Pati, Madhu Sharma and P.S. Ahuja Division of Biotechnology, Institute of Himalayan Bioresource Technology, Palampur-176 061 (Himachal Pradesh), India IHBT Publication Number: 9928 Keywords : Rosa damascena, Rosa bourboniana, Damask rose, in vitro multiplication, microshoots, rooting, hardening, direct regeneration, protoplast fusion. 1. Abstract Damask rose, Rosa damascena, an important species among the scented roses, yields a highly fragrant commercially important essential oil. It is commonly used in perfumery industry, beverages, soft drinks, medicines etc. Besides rose oil, the other products are rose water, rose concrete, rose absolute, "gulkand" (a sugary preperation) etc. R. bourboniana, a related species, is also used also used for rose oil extraction. For achieving faster rates of multiplication, tissue culture methods are best employed and may be of great commercial value in establishing plantations. Micropropagation protocols using nodal segments were established in R. damascena and R. bourboniana. Rooted plants were transferred to field. In addition protoplast culture studies were also carried out in the two species of scented rose. Friable callus was initiated from stem and leaf segments inoculated on Murashige and Skoog (1962) medium supplemented with varying concentrations of 2,4-D (1-10 μM), NAA (1-10 μM), BAP (1-10 μM). Efficient protoplast culture procedures have been worked out from cell suspension as a source, however, regeneration of plants posed a developmental block in both parental and hybrid calli. Alternative explants for their regeneration potential are under assessment and promising results are obtained for genetic manipulation of these important essential oil bearing rose species. 1. Introduction Rose is one of the most important ornamental crop and for centuries it is grown as garden plant and cut flower. Among 120 species of roses, only a few are scented which are suitable for production of rose oil, rose water, rose concrete, rose absolute etc. Of these, damask rose (Rosa damascena), R. centifolia and R. bourboniana are commercially grown in India. Damask rose is generally prefered over other scented species for its highly priced rose oil, which is commonly used in cosmetics, beverages, soft drinks, medicines etc. Major constraints in rose improvement are, i) conventional breeding methods are slow due to perennial nature of the crop. ii) high degree of sterility caused by discordant chromosome numbers, iii) infestation by pests, fungal (black spot, powdery mildew, die back etc.) and viral diseases thereby, causing huge loss to the crop, and iv) narrow genetic base. In view of the existing problems, perhaps the biotechnological tools can facilitate improvement in roses. One of such tools is in vitro method, which ensures rapid multiplication of elite clones and production of healthy, and disease free plants. Protoplast technology and genetic transformation coupled with regeneration protocol can also play important roles in the improvement of the genus Rosa. In the present paper, micropropagation, regeneration and protoplast isolation and culture were attempted. Thin Alginate Layer (TAL) technique (Golds et al., 1992) for protoplast culture was successfully employed for the first time in the genus Rosa. Some of