Effect of NAA on Ex vitro Rooting of In vitro Derived Microshoots of Elite Sugarcane (Saccharum officinarum L.) Genotypes

Root formation of rootless in vitro microshoots can be induced ex vitro with auxin during ex vitro acclimatization period to shorten the procedure and to reduce plantlet production cost of micropropagation. Hence, this study was carried out using a completely randomized design to determine the effect of different concentrations of auxin (0, 10, 20, 30, 40 mg/l) on ex vitro root development of sugarcane microshoots. The basal end of the shoots was dipped in auxin solution overnight before the shoots were transferred into a plastic tray containing a mixed growing medium in green house. The results showed that for genotype N52, best root formation was found on the shoots treated with 20 mg/l NAA by which rooting frequency was 76% with 5.88±0.04 cm root length and 8.06±0.13 number of roots per plantlets. While in genotype N53 maximum root formation was recorded on the shoots dipped in 30 mg/l NAA by which rooting frequency was 70% with 5.42±0.11cm root length and 4.52±0.19 number of roots per plantlets. Shoots rooted through this method exhibited 100 % survival in both genotypes. Keywords: Microshoot, ex vitro, Auxin, in vitro, Acclimatizatio