Enhanced dormancy release and emergence from potato tubers after exposure to a controlled atmosphere

Abstract

The North American potato industry requires an effective and environmentally-appropriate, dormancy-release methodology. The present study examined dormancy release and subsequent sprout emergence based on a modified, controlled-atmosphere (CA) approach using such environmentallycompatible gases as nitrogen, carbon dioxide and oxygen with or without trace amounts of ethylene (50 ppm). This paper is the first published report of a semi-automated, controlled-atmosphere system for dormancy release of potato tubers. The system allows computer-controlled gas application and analysis for up to four gas mixtures simultaneously. Low oxygen concentrations (< 10%) for 10 days in the presence of 10 to 60% carbon dioxide or a high carbon dioxide (60%)/oxygen (40%) treatment caused tuber breakdown regardless of cultivar. The most effective mixtures for enhanced dormancy release and sprout emergence were 20% CO2/40% O2 or 60% CO2/18-20% O2 and their effects were further enhanced by 50 ppm C2H4 (ethylene). In the presence of 50 ppm C2H4 the 20% CO2/40% O2 mixture was comparable to bromoethane in effectiveness. Temperature and light exposure affected subsequent Russet Burbank tuber responses to CO2/O2/C2H4 gas mixtures.