Effects of Ethephon on Abscission of Vegetative and Reproductive Structures of Phaseolus vulgaris L.1

Abstract (2-Chloroethyl)phosphonic acid (ethephon) at 250 ppm controlled bud and flower abscission but not young pod abscission of ‘Dark Red Kidney’ bean. Leaf abscission was unaffected, intemodal elongation was temporarily retarded, and the number of seeds but not the number of pods produced exceeded that of untreated plants but the difference in seed production was not significant. Treatment with 500 ppm ethephon resulted in a pattern of abscission similar to that of untreated plants. At higher concentrations (1000 and 2000 ppm) abscission of reproductive structures and of leaves was promoted. Seed production, seed maturity, and seed size were reduced. New leaves were pendant and were smaller than those of untreated plants.