THE RESPONSE OF SELECTED Phaseolus vulgaris L. CULTIVARS TO OZONE UNDER CONTROLLED FUMIGATION AND AMBIENT FIELD LEVELS

Abstract

In 1977, a cross section of the Phaseolus vulgaris L. world collection was screened for ozone insensitivity in fumigation chambers. A number of cultivars were selected for their high level of insensitivity to ozone (O₃). These selections, along with three cultivars reported as highly insensitive and a number of white bean cultivars, were further evaluated under more stringent conditions in a controlled environment as well as under field conditions over a 2-yr period. All the white bean cultivars were sensitive to O₃ under controlled conditions, but under field conditions later maturing cultivars escaped serious injury from ambient O₃ levels. Early-maturing white bean cultivars tended to suffer reduced yields and earlier senescence compared with plots chemically protected from ambient O₃ injury. The yields of cultivars selected as O₃ insensitive in chamber fumigations were not affected by ambient field O₃ levels in the field trials.