In vitro Study of Role of Ethylene During Tillering in Sugarcane

Abstract

The effect of ethylene on tillering of sugarcane cv. Co Pant 84211 was studied under in vitro conditions. A rapid and efficient protocol for shoot regeneration from meristematic tissue has been developed by using various combinations of growth regulators. In vitro raised, 6–8 weeks old, sugarcane plantlets with 2, 5 and 10 tillers were subcultured in sealed bottles. During tillering the tiller bud initially showed a slow rate of elongation accompanied by swelling. It was followed by a more rapid rate of elongation. Ethylene production in shoot segment containing tiller bud was found to occur at the onset of tiller swelling during inflorescence emergence. The levels of ethylene were measured by gas chromatography after incubating them for different time intervals starting from 48 to 240 h. Ethylene levels decreased with increase in time period. To further check the role of ethylene during tillering of sugarcane, different concentrations of exogenous ethylene and inhibitor of ethylene biosynthesis (AVG, AOA and CoCl2) were applied to the bunches of 5 tillers. 10 ppm ethylene and 15 ppm ethrel application caused 200 and 210 % increase in tiller production whereas higher concentration exhibited toxic effects. Ethylene biosynthetic inhibitors adversely reduced the number of tiller production. These results indicate that ethylene plays a role in promoting tiller swelling during the onset of tiller release from apical dominance and may act as a modulator hormone in promoting tiller elongation in the presence of cytokinin.