Yorgancilar and Erisen J. Anim. Plant Sci. 21(3):2011 519 THE EFFECT OF THIDIAZURON (TDZ) ON SHOOT REGENERATION OF ASTRAGALUS SCHIZOPTERUS M. Yorgancilar and S. Erisen * Selçuk University, Faculty of Agriculture, Department of Field Crops, 42075 Konya, Turkey * Selçuk University, Ahmet Keleşoğlu Education Faculty, Department of Biology Education, 42090 Konya, Turkey Corresponding author’s e-mail: myorg@selcuk.edu.tr ABSTRACT The effect of thidiazuron (TDZ) on shoot regeneration of the endemic Astragalus schizopterus was investigated in Turkish flora. Explants (leaf and petiole) were cultured on the basic medium Murashige and Skoog (MS) containing various plant growth regulators (PGRs) [0.0, 0.4, 0.5, 0.6 mg l -1 thidiazuron (TDZ); 0.4, 0.5, 0.6 mg l -1 TDZ x 0.1, 0.2 mg l -1 α-naphthaleneacetic acid (NAA)] to induce shoot bud induction. The combinations and concentrations of PGRs showed significant variations for the frequency of callus formation, appearance of callus and the potential of callus differentiation. Callus formation occurred in cultures, but it was not obtained in adventitious shoot regeneration. Therefore, rapid multiplication was made by using lateral meristem which were obtained from 4 weeks sterile seedling. Lateral meristems were cultured on basic media MS containing various PGRs 0.5, 1.0 mg l -1 zeatin (ZEA), benzyladenine (BA) and 0.22, 0.5 and 1 mg l -1 TDZ. The highest number of shoots (23.6/explants) was obtained on MS medium containing 1 mg l -1 TDZ followed by MS medium cointaining 1 mg l -1 BA which produced 15.80 shoots per explant. It was observed that shoots didn’t have healthy development in all media containing TDZ. So it was suggested that BA is a useful PGR for rapid multiplication in A. schizopterus. The regenerated shoots were transferred to rooting medium [MS with 0.5-1 mg l -1 NAA and 0.5-1 mg l -1 indole-3-butyric acid (IBA)] where they successfully rooted (100%) and showed rapid elongation. Rooted shoots were transferred to the ex vitro and produced normal plants. Key words: Astragalus, endemic, lateral meristem, micropropagation, callus induction. INTRODUCTION Astragalus species are important and are used in many different way and areas in medicine because of their secondary metabolites (Tang, 1992; Karagöz et al., 2007). Some species are important for animal nutrition. Deep top root system makes these species can be used for erosion control (Erisen et al., 2010a) and establishing the pasture in the non-irrigated areas such as Karapınar (Acar et al., 2011). At the same time the genus Astragalus contains annual or perennial species. Some of them can resist to abiotic stress such as cold, salinity and drought etc. and can grow in a wide range of conditions. However, slow seedling development, poor seed germination capacity and low number of seed set are drawbacks affecting their wider adaptation capabilities requiring the application of tissue culture techniques for their propagation. There are studies indicating the obtaining of adventitious shoot regeneration via organogenesis and embryogenesis in species such as Astragalus adsurgens (Luo and Jia, 1998ab), Astragalus cicer (Uranbey et al., 2003; Başalma et al., 2008), Astragalus melilotoides (Hou and Jia, 2004), Astragalus polemoniacus (Mirici, 2004), Astragalus chrysochlorus (Turgut-Kara and Arı, 2008), Astragalus cariensis (Erisen et al., 2010a), Astragalus nezaketae (Erisen et al., 2010b). However, there are a small number of research in vitro multiplication of this genus such as Astaragalus duranii (Çöçü et al., 2005), Astragalus maximus (Turgut-Kara and Arı, 2006) and Astragalus nitidiflorus (Cano-Castillo et al., 2009). Thidiazuron (TDZ), is one of the cytokinin like substances, has often been used in the shoot regeneration system in recent years. However when TDZ was using for shoot regeneration it can lead to negative effects viz. hyperhydricity and poor shoot devolopment (Huetteman and Preece, 1993). Astragalus schizopterus L. that belongs to Proselius section is an endemic species and cluster- shaped, woody at the base, creeping users, consists of perennial herbaceous plants (Davis et al., 1988). This plant has the potential to become fodder for animal feed. There has not been any report on tissue culture of A. schizopterus. This studies overall goals were to investigate the effect of TDZ on shoot regeneration and to develop a propagation procedure for the multiplication of A. schizopterus. In this paper, report the original results of investigations to establish micropropagation of A. schizopterus is reported. MATERIALS AND METHODS A. schizopterus seeds collected from a wild population (Burdur: Dirmil-Gölhisar, 7. km, 1175 m, The Journal of Animal & Plant Sciences, 21(3): 2011, Page: 519-524 ISSN: 1018-7081