UNDERSTANDING THE UNDERLYING MECHANISMS BY WHICH ETHYLENE SUPPLEMENTATION EXTENDS STORAGE LIFE OF ONIONS AND POTATOES

Ethylene is known to have profound effects on the postharvest quality of climacteric fresh produce. Understandably, far less emphasis has been given to understanding the role that ethylene might have in the regulation of dormancy or senescence in non-climacteric systems. It is now well established that continuous ethylene supplementation can extend the storage life of onions and potatoes even though these organs are low ethylene producers. In potato ethylene triggers dormancy break, but also inhibits sprout growth. In onion, both ethylene and the ethylene antagonist 1-methylcyclopropene (MCP) inhibit sprouting, suggesting a surprisingly similar pattern of control. Indeed, 1-MCP may act synergistically when combined with ethylene. Given this apparent dichotomy, the underlying mechanisms of hormones in regulating entry into dormancy, dormancy release and rate of post-dormant sprout growth will be discussed since new evidence suggests that abscisic acid has a role in establishing dormancy.