ABSORPTION, TRANSLOCATION, AND METABOLISM OF AC-263,222 IN SELECTED SOYBEAN (GLYCINE-MAX) CULTIVARS

The goal of this research was to determine if differing levels of tole rance to AC 263,222 exist in soybean, C-14-AC 263,222 was foliar-appli ed to 'Coker 6955,' 'Hartz 6686, 'Hutcheson,' '9581 Pioneer,' '9681 Pi oneer,' and 'RA 606' soybean cultivars, Differential absorption of C-1 4-AC 263,222 was evident among cultivars 48 and 96 h after application , Movement out of the treated leaf was both acropetal and basipetal, i ndicating xylem and phloem mobility, Although absorption and transloca tion differences occurred among cultivars, these differences do not ex plain the differential response of soybean cultivars to AC 263,222. Me tabolism of C-14-AC 263,22 differed greatly among cultivars and increa sed with time. Ninety-six h after application, 9581 Pioneer metabolize d 66% of the absorbed C-14-AC 263,222, compared to RA 606, which metab olized only 41%. The large differences in metabolism that occurred 48 and 96 h after application suggest that metabolism is responsible for the differential response of soybean cultivars to AC 263,222.