Adventitious Shoot Production using Petiole Explants through Direct Regeneration in Sugar Beet

Sugar beet (Beta vulgaris L.) is one of the two very important sugar crops in the world. Transgenic experiments, including tissue culture practices play a pivotal role in the investigation of the any gene function as well as introducing new functionally important genes. Tissue culture is inevitably required to employ any transgenic methods for making transgenic plants. Therefore, to find an appropriate explant to produce adventitious shoots in recalcitrant sugar beet plants without continuous seed germination, a completely randomize design (CRD) was carried out in a factorial arrangement. The adventitious shoots produced on leaves through direct regeneration method, were used as in vitro explant. Petiole and leaf disc explants were studied in two positions, located close and far from terminal buds in two sugar beet lines (SBSI-04, SBSI-02). After four weeks and two consecutive sub-culturing in MS basal medium supplemented with IBA (0.1 mgl-1) and BAP (0.25 mgl-1) hormones, the number of shoots were counted and compared as percentage. Results of this study showed that the petiole explant produced the highest number of shoots. Furthermore, the number of the shoots was higher in SBSI-04 line than SBSI-02 line. Interestingly, the position of leaf explants had a significant effect on the number of shoots produced. Interior petiole explants, produced more shoots in SBSI-04 line as compared to the leaves farther than terminal buds, suggesting for producing transgenic sugar beet plants, interior petiole explants are recommended.