IMPACT OF SEASONAL OZONE EXPOSURE ON YIELD AND VEGETATIVE GROWTH OF PRIMOCANE-FRUITING RASPBERRY

Factorial experiments in two growing seasons in open-top field chambers with two or three 03 concentrations and two primocane-fruiting raspberry (Rubus idaeus L.) cultivars were used to obtain dose-response relationships describing the effects of seasonal 03 exposure on raspberry plant vegetative and reproductive growth. At the lower concentration (0.12 mul.liter-1), the response to 03 was nonsignificant. However, at 0.24 mul-liter-1, 'Heritage' showed a significant decline relative to the control in cane height, node count, cane diameter, and dry weight. These changes were accompanied by a 52% decrease in yield, caused mainly by a reduction in fruit count. In contrast, vegetative and yield characters of the 'Redwing' were not affected by O3.