Cumulative effect of thidiazuron and 1-naphthylacetic acid in massive root proliferation of micropropagated sugarcane plantlet

: Thidiazuron (TDZ), a well known plant growth regulator is used in tissues culture as a sup-plement to the basal MS medium. Several reports suggest the role of TDZ in promoting plant organogenesis and plant regeneration. Our experiments to micropropagate the sugarcane using various growth regulators reveal the role of TDZ in rooting and survival of a high yielding new sugarcane variety Co 05011. Various permutation combinations were tried using TDZ as the main regulator to rapidly in-crease the number of plantlets. Shoot cultures were repeatedly multiplied for 10 cycles and then transferred to MS medium augmented with various concentration of TDZ along with 1-naphthylacetic acid (NAA) and sucrose for rooting. Results of present study indicate optimum concentration of TDZ (0.002 mg/L) in combination with NAA (0.5 mg/L) resulted in 93.6% root formation. Moreover, when these shoots were re-cultured in the same media for an-other two cycles it produced 100% rooting and had almost 100% survival during acclimatization. These results indicate that TDZ and NAA combination enhance the activity of NAA and resulting in massive proliferation of roots. TDZ increases the frequency and proliferation of healthy and vigorous roots in micropropagated shoots thus enhancing their survival rate in field and during hardening process. This work can be helpful in developing successful and cost effective tissue culture of elite sugarcane varieties.