SEED CHARACTERISTICS AND NUTRIENT COMPOSITION OF SELECTED BEANS (PHASEOLUS-VULGARIS L) WITH DIFFERENT OZONE TOLERANCE

Ozone sensitivity, nutritional quality, seed characteristics, and grow th habit of beans (Phaseolus vulgaris L.) were evaluated in two separa te experiments. In the first experiment the data showed a significant variation among 34 bean accessions for ozone sensitivity following acu te exposure of 18-day-old plants to 0.6 mul/l O3 for 2 hours under env ironmentally controlled greenhouse conditions. PI-163579, PI-169735, P I-171790, PI-176684, PI-201374, PI-310711, PI-345576, PI-370569, PI-37 9435, and PI-414831 were identified as tolerant to acute ozone exposur es. Protein, oil, starch, sugar, and ash contents in the seed of selec ted germplasm were determined and no correlation was found between the se components and ozone sensitivity. Seed size and growth habit varied considerably among the 34 accessions but were not correlated to ozone sensitivity. In a second experiment, ten accessions, selected from th e tolerant ones identified in the first experiment, were subjected to chronic ozone exposure in open-top chambers at 0.04 and 0.08 mul/l con centrations for 7 hours/day 44 days after transplanting. Based on foli ar injury and yield reductions, only PI-370569 and PI-414831 were tole rant to prolonged ozone exposure (0.08 mul/l). A significant positive correlation (r=0.83) existed between foliar injury rating from chronic treatments involving 0.04 and 0.08 mul O3/l and acute exposure (0.6 m ul O3/1/2 hours). The data indicated that acute ozone exposure can be used to initially screen a large number of bean accessions, however, t his is an imperfect indicator of ozone sensitivity with chronic exposu re.