Study on Effects of Different Plant Growth Regulators Types in Shoot Regeneration and Node Formation of Sutsuki Azalea (Rhododendron indicum): A Commercially Important Bonsai

Sutsuki azalea with botanical name Rhododendron indicum is one of the oldest evergreen azaleas, not only considered as a famous ornamental shrub, but also as a medicine to treat disease. Sutsuki azaleas are popular bonsai plants for many reasons. The overall goals of this research are to establish the most suitable cytokinin for in vitro shoot regeneration of Sutsuki azalea. The influence of Plant Growth Regulators was studied on shoot numbers, shoot length and node numbers after 10 weeks. In current experiment, after sterilization the apical shoots contain 4 developing leaf primordia separated and were cultured on ½ Anderson medium with different hormonal treatments. In this stage included three levels of isopentil adenin (2ip) (0, 2, 10) mg/l, Zeatin (0,0/1,0/5) mg/l and Thidiazuron (TDZ) (0, 0/04, 0/2) mg/l that were studied two concentration of hormones with each other. The results showed that 10 mg/l 2ip together with 0/2 mg/l TDZ was the best treatment for increasing the shoot number and 10 mg/l 2ip together with 0/1 mg Zeatin were the best treatment for increasing shoot length and node number.On the basis of available literature, this is the first and significant study regarding the comparative effect of different PGRs on in vitro propagation study of R. indicum. This significant study could be useful for large scale propagation and regeneration of this valuable bonsai.