Zion, B., Institute of Agricultural Engineering, Israel
Arbel, A., Institute of Agricultural Engineering, Israel
Halaly, T., Institute of Plant Sciences, Israel
Regev, R., Institute of Agricultural Engineering, Agricultural Research Organization, Bet Dagan, Israel
Barak, M., Institute of Agricultural Engineering, Agricultural Research Organization, Bet Dagan, Israel
Lidor, G., Institute of Agricultural Engineering, Agricultural Research Organization, Bet Dagan, Israel
Weissblum, A., Institute of Agricultural Engineering, Agricultural Research Organization, Bet Dagan, Israel
Harcabi, E., Ministry of Agriculture and Rural Development, Bet Dagan, Israel
Or, E., Agricultural Research Organization, Institute of Plant Sciences, P.O. Box 6, Bet Dagan, 50250, Israel

In warm-winter regions, where early ripening of table grapes is enabled by the climate, prolonged dormancy is a major delaying obstacle to early-season marketing. Successful production in these regions depends on chemically or physically overcoming the dormancy cycle to compensate for lack of natural chilling. It was previously shown that heat shock from hot air at 150°C induces dormancy release of detached grapevine buds under a controlled environment. In the present study, a heat-shock generator (HSG) for enhancement of dormancy release of whole vines was developed and tested under field conditions. The HSG heats a partially-enclosed volume of air to a required temperature and conveys it through the vines at a speed that results in the desired exposure duration. Heat shocks of 150°C for 15 and 30 s applied in situ to dormant cv. Muscat of Alexandria vines induced earlier dormancy release and significantly greater yield (156%) relative to the control. A longer heat shock of 90 s negatively affected the dormancy release. The HSG is similar to other common agricultural practices in operational simplicity, and its cost and environmental benefits make it a viable alternative to chemical application. © 2012 American Society of Agricultural and Biological Engineers.