Effects of Plant Growth Regulators on In vitro Root Development of Eucalyptus Hybrid Clones

Pattama Tongkok, Jittraporn Chusrisom, Pussadee Sukpiboon, Eakpong Tanavat, Pavina Badan, Kasem Haruthaithanasan, Tepa Phudphong, Weerasin Sonjaroon, Nisa Leksungnoen and Chatcharee Kaewsuralikhit



The effects of plant growth regulators (PGRs) on root induction of three commercial clones of Eucalyptus hybrid were investigated under aseptic conditions, including KAPI 12, KAPI 114, and KAPI 115. Shoots from 1-year-old stock plants of each clone were cultured in Murashige and Skoog (MS) media supplemented with different concentrations of ?-naphthylacetic acid (NAA), Indole butyric acid (IBA) and Abscisic acid (ABA). Sixteen different culture media were tested in the experiment. The results showed an effect of the culture medium on the root induction of three commercial clones of Eucalyptus hybrid. The different IBA concentrations combined with ABA had shown positive effects on root formation and development. The average number of roots and root lengths under these combinations were significantly different from the average number of roots on the PGR free medium. The result showed 100% rooted plant when compared with control at 1%. The optimum medium for induction and development of roots is MS medium supplemented with 2 mg/l IBA + 0.2 mg/l ABA+ 0.3 mg/l PVP+15 g/l Sucrose + 5 g/l Agar. The highest average number of adventitious roots of KAPI 12, 114 and 115 after 3 weeks under standard culture conditions were 8.8 ? 0.63, 7.7 ? 0.67 and 13.6 ? 1.17, respectively. The highest root length of KAPI 12, 114 and 115 were 55.47?7.71, 74.23?6.87 and 74.98?4.02 mm, respectively. This research shows the suitable concentration of PGRs that have been used for micropropagation and rooting of three commercial clones of Eucalyptus hybrid by plant tissue culture technique.