Uman National University | today: 05/20/2026
| Author(s) | Блятник Т. С., , , | ||
|---|---|---|---|
| Category | The Agronomy | ||
| year | 2026 | issue | Issue 108 part 1 |
| pages | 87-93 | index UDK | 631.811.98:[631.559:633.34(292.485) | DOI | 10.32782/2415-8240-2026-108-1-87-93 (Link) |
| Abstract | The purpose of the research was to substantiate the effectiveness of the effect of retardants on soybean yield depending on the timing of application in the conditions of the Western Forest-Steppe. Field experiments were conducted during 2023–2025 at the production unit of Private Enterprise «Zakhidnyi Bug», located in the village of Shymkivtsi, Ternopil district of the Ternopil region. The research design involved a two-factor experiment. Factor A included the timing of retardants application: the 3rd trifoliate leaf stage, budding and flowering. Factor B comprised the following treatments: 1) water spraying (control); 2) Mepiquat Chloride + calcium prohexadione, 1,0 l/ha; 3. Chlormequat- chloride 750, 1,5 l/ha; and 4. Ethephon, 1,5 l/ha. The soybean variety Kioto, classified as medium-early, was grown in the trial. The experiment was arranged in three replications. The study was conducted using standard research methodologies. Foliar application of retardants during the growing season resulted in an increase in soybean seed yield. The highest treatment efficiency was observed when the substances were applied at the 3rd trifoliate leaf stage. In this phase, the mepiquat chloride + calcium prohexadione and chlormequat-chloride 750 treatments yielded 4,28 and 4,34 t/ha, respectively, exceeding the water-sprayed control by 0,25 and 0,19 t/ha. Application of the ethephon morphoregulator resulted in a yield of 4,41 t/ha, providing the highest increase of 0,32 t/ha. A reduction in effectiveness was noted when retardants were applied at the budding stage. Yield increases relative to the untreated control were 0,21 t/ha for mepiquat chloride + calcium prohexadione, 0,16 t/ha for chlormequat-chloride 750, and 0,26 t/ha for ethephon. The lowest yield gains were recorded when growth regulators were applied during flowering, due to a of crop lodging. Yield increases in this phase reached only 0,12, 0,08, and 0,15 t/ha for mepiquat chloride + calcium prohexadione, chlormequat-chloride 750, and ethephon, respectively. Across all application stages, ethephon demonstrated the strongest morphoregulatory effect. Thus, the application of a retardant based on the active ingredient ethephon in the 3rd trifoliate leaf phase ensures maximum realization of the productivity potential of soybeans. | ||
| Key words | soybean, retardants, application stage, yield | ||