Pengaruh Pemberian Giberelin terhadap Pertumbuhan dan Produksi Empat Varietas Kedelai (Glycine max L. Merrill)

Abstract

Growth regulators such as gibberellic acid (GA3) is expected to remove and prevent barriers imposed by genetic
and enviromnental effect on plant growth and supposed to increase crop production. In this study, we intended to
determine the effect of GA3 on agronomic and yield components of four soybean varieties. The field experiment was
arranged in a split plot design with three replications. Three levels of GA3 concentrations such as 0 ppm as control, 125
ppm and 250 ppm were assigned as main plot and sprayed over the plant at 21 days after planting. Four varieties
including Kaba, Grobogan, Wilis and Anjasmoro were used as subplots and the seed of each variety was sown in a plot
size of 3,2 m x 3 m. Several growth parameters and yield components were observed from each plot. The results showed
that GA3 effect was inconsistent for the four varieties. It appeared from this study that GA3 did not affect leaf area index,
time to flower, time to harvest, number of filled pods per plant, seed number per plant, and harvest index for all varieties.
Application of GA3 at levels of 125 and 250 ppm increased crop growth rate, plant height and internode length of main
stem in all genotypes except Anjasmoro. The main impact of different levels of GA 3 application was an increase in seed
weight per plant and grain yield. The highest grain yield was achieved with application of 125 ppm GA 3 for Kaba and
Grobogan and of 250 ppm for Wilis and Anjasmoro. This imply that application of GA 3 to soybeans genotypes has to be
taken care with cautiously according to the genotypes.