PLANT GROWTH STIMULANT APPLICATION ON WINTER COMMON BEAN CULTIVARS

The use of plant growth stimulants for increasing crop yield has recently called the attention of researchers, but some results have proved contradictory. For that reason, the objective of this study was to evaluate the effects of plant growth stimulant application on components and grains yield of two winter common bean cultivars under Brazilian savannah conditions. The experiment was conducted during the 2007 fall-winter season, at the Unesp experimental farm, Ilha Solteira campus, in Selvíria, Mato Grosso do Sul State, Brazil. The experimental design was randomized blocks, in a strips scheme, with four replications. The treatments consisted of a combination of five plant growth stimulant doses (0 L ha-1; 0.5 L ha-1; 1.0 L ha-1; 1.5 L ha-1; and 2.0 L ha-1), composed of three vegetable hormones (kinetin, gibberellic acid, and indolbutyric acid), in two application periods: at the vegetative stage (V4) and at the reproductive stage (R5). Vegetative characteristics such as plant height, first pod insertion height, number of grains per pod, and weight of 100 grains were not affected by the product application. However, its application at the reproductive stage (R5) increased the number of grains per plant and grain yield of the Carioca Precoce and IAC Apuã bean cultivars. For that increase, 2 L ha-1 was the best plant growth stimulant dose. KEY-WORDS: Phaseolus vulgaris; yield components; application period.