EFFECT OF TIME OF DESICCATION ON OIL CONTENT IN DIFFERENT SUNFLOWER HYBRIDS / EFECTO DEL TIEMPO DE DESECACION SOBRE EL CONTENIDO DE ACEITE EN DIVERSOS HIBRIDOS DEL GIRASOL / EFFET DU TEMPS DE DESSICCATION SUR LE CONTENU EN HUILE DANS DIFFÉRENTS HYBRIDES DE TOURNESOL

SUMMARY Chemical desiccation with Reglone Forte has been tried in production fields under four sunflower hybrids. Reglone Forte (2 l/ha) was applied at 7-day intervals from the end of pollination till maturity. Seed moisture was determined prior to each treatment. Seed oil content was determined at maturity, using the method of nuclear magnetic resonance. The highest oil content was found in the control, the lowest in the treatment 7 days after flower (DAF). The absence of significant differences among treatments 21 DAF, 28 DAF and the control was an indication that there was no large increment in oil content in the period after the average seed moisture reached 44.34% and maturity. Considering individual hybrids, there was no large oil content increase already from treatment 14 DAF, with the exception of hybrid NS-H-43 which evidently required a later treatment. Considering the time of treatment in relation to seed moisture, this hybrid achieved maximum oil content when treated at 31% seed moisture. In hybrid NS-H-26 RM, however, maximum oil content was achieved with treatment at 25% seed moisture.