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Abstract
Improvement of ornamental plant characteristics such as longer vase life, high productivity, new flower form and plant morphology, resistance to diseases……etc., is the goal of all breeding programs since breeders are looking for new and attractive characteristics which are high demand by the consumer, who continually searching for new products.Likewice, biotech-nological methods represent efficient tools, parallel with classical breeding, in improving and selecting superior genotypes. Both Yucca (Yucca elephantipes L.) and carnation (Dianthus caryophyllus L.) are of considerable importance as commercial ornamentals.
Yucca is an evergreen, monocotyledonous plant, which belongs to Family Agavaceae. It is of particular interest to garden landscaping in arid and semi-arid regions for its outstanding ability to grow under these conditions. Yucca also, is a popular plant for indoor decoration. The importance of Yucca is increasing because some important steroidal saponins have been isolated from leaves and rhizomes that can be used as antiarthritic, purgative and detergent (Bahuguna and Sati, 1990; Navin et al 1992). Propagation of Yucca by cuttings and offsets produces few plants. Micropropagation offers major production and marketing advantages over traditional propagation methods. Therefore, the present research was conducted to develop a rapid procedure for multiplication in vitro, rooting and acclimatization in order to facilitate the release of the used Yucca genotypes at large scale production.
Likewise, carnation (Dianthus caryophyllus L.) is a member of Caryophyllaceae family and a native of the Mediterranean area (Dole and Wilkins, 1999). This plant is one of the world’s most popular, economic and important cut flowers due to perpetual flowering (Mii et al, 1990) and the presence of new single-and multi-colour cultivars (Dole and Wilkins, 1999). Carnation cultivars have high heterozygosity and must be vegetatively propagated (Mii et al, 1990). Its traditional method is both slow and ineffective, especially in the absence of fungal and viral diseases control, leading to low yields and poor quality cut flower production (Wabule et al, 1991). Thus, there is a need to explore other more effective methods of propagation.Hence plant tissue culture techniques could offer an opportunity to provide a good start in the production of good quality of carnation cut flowers that can, adequately, compete in the international markets.Moreover, plant regeneration is essential, also,requeset ,for crop improvement in general. However, selection on callus level requires an effective and reliable system for initiating, maintaining and subsequently, regenerating plants from callus. Establishing a culture system capable of plant regeneration is a prerequisite step before conducting any in vitro selection experiment (Barakat and Abdel – Latif, 1995).
The present investigation was conducted to determine the regeneration capability of ten carnation cultivars. In addition, two in vitro selection procedures were applied for developing Fusarium resistant mutant plants from the selected carnation cultivars and detection of genetic polymorphism among carnation somaclones and their parents using RAPD analysis.
CHAPTER 2