Micro propagation of sugarcane {Saccharum officinarum L.) through auxiliary buds

Abstract

Sugarcane (Saccharum officinarum L.) is an economically important plantation crop in Sri Lanka. There is a need to identify new vegetative propagation methods for mass scale production o f commercial varieties o f sugarcane to maintain clonal uniformity. In this study experiments were carried out to find the proper surface sterilization procedure, proliferation and rooting media and proper acclimatization process to complete the micro-propagation cycle for sugarcane auxiliary buds. Three different concentrations o f Clorox (5.25% NaOCl) (15% (v/v), 20%o (v/v), and 25% (v/v) with three different time durations (10, 15, 20 min.) were tested for survival percentage o f in- vitro cultured auxiliary buds o f sugarcane. Explants were established on MS (Murashige and Skoog, 1962) medium transferred to proliferation media with four different concentrations o f BAP (Benzine Amino Purine) (0.5, 1.0, 1.5 and 2 mg/l) and 0.4 mg/l IB A (Indol Butyric Acid). To reduce browning, incorporation o f 0.1 g/l Poly Vinyl Pyrolidone (PVP) to culture media was also tested. To induce in- vitro rooting, addition o f 1.0 g/l activated charcoal to MS medium with four different concentrations o f IB A (0.5, 1.0, 1.5 and 2.0 mg/l) with 0.2 mg/l BAP were tested. Suitable acclimatization procedure was tested with different combinations o f sterilized sand and coir dust (1:0, 0:1, 1:1, 2:1 and 1: 2) as potting media for the acclimatization o f in vitro derived plantlets. Results revealed that 25%> (v/v) Clorox for 20 min exposure time was the best surface sterilization procedure for sugarcane auxiliary buds. MS medium with 1.0 mg/l BAP and 0.4 mg/l IB A gave the highest proliferation rate (1:10) after eight weeks. The incorporation o f 0.1 g/l PVP to the same medium reduced browning that occurred in the medium with out effects on shoot proliferation and growth. Highest root initiation rate and higher number o f roots were observed in MS medium with 1 mg/l IB A, 0.2 mg/l BAP and 1 g/l activated charcoal. The most suitable potting medium for acclimatization o f in vitro raised plantlets was found to be sand: coir dust at 1:2 ratio in which 100% survival rate was observed.