Reduction of Tomato Fruit Size and Yield by Ozone1

Abstract

Abstract A multiple regression analysis of yields of ‘6718 VF’ tomato (Lycopersicon esculentum Mill.) from 11 field plots along an ambient ozone gradient in southern California indicated that ozone was responsible for a significant reduction in fruit size. Ozone dose accounted for 85% of the reduction in fruit size and was at least 3.3 times more important than any of the monitored meteorological variables in predicting the percentage of marketable fruit. High ambient ozone depressed production and caused a significant decrease in fruit size over time. A model describing the reduction in marketing container yield (% reduction = 0 + (.0232 x dose)) predicted a 50% reduction at a dose of 2000 pphm-hours > 10 pphm.