Response of Cultivars of Soybean to Synthetic Abscisic Acid

This paper describes work to determine whether soybean cultivars differ in their physiological response to applied abscisic acid. ABA is a naturally occurring plant hormone that affects a number of physiological processes, including leaf abscission, leaf senescence, seed germination, bud dormancy, flowering, and tuberization (4). Usually, ABA is applied in various concentrations to whole plants or plant parts. Environmental factors (3), duration of photoperiod (2), and plant age (4) affect the plant or plant tissue response to ABA. Reports of genotypes of a species responding differently to ABA are rare (see de Fossard in Addicott and Lyon, References 1, 3). However, in most experiments only one cultivar of a species is tested for a response to ABA. We applied ABA to 34 soybean cultivars.