Document Type: Research Paper
Facultad de Ciencias Agrarias, Universidad Nacional de Lomas de Zamora, Ruta 4 Km 2, Llavallol (1836), Buenos Aires, Argentina
Facultad de Ciencias Agrarias, Universidad Nacional de Lomas de Zamora, Ruta 4 Km 2, Llavallol (1836), Buenos Aires, Argentina.
Advanta Semillas, Ruta 33 Km 636 (2600), Venado Tuerto, Argentina.
The impact of chemical desiccation on yield showed contrasting results depending on seed
moisture content at the time of application. Its effects on seed deterioration are still unknown
and could be modified by seed composition. Objectives were to evaluate the impact of chemical
desiccation on: i) hybrid sunflower seed yield and composition at harvest time, ii) seed
deterioration during long-term storage and iii) the relationship between seeds deterioration and
oil or oleic acid content. Six hybrids including low, mid and high oleic were evaluated in three
experiments. Two treatments were applied on female lines at 27-30% seed moisture:
(i) spraying with Paraquat and (ii) detaching heads with a knife. Control remained in the field
until 10% seed moisture. Seeds were stored during 19 months under room and cold chamber
conditions. Yield, number of seeds and hybrid seed composition (thousand seed weight, kernel
percentage, oil and acid oleic content) were determined. Seed deterioration during storage was
analyzed by germination and vigour. Paraquat advanced harvest by 35-43 days, without
affecting yield or seed composition. During storage the germination of Paraquat treatments
remained above that of control, without differences between storage conditions, while vigour
remained above control only in cold chamber, for low oleic hybrids. Associations between
deterioration (germination and vigour) and oil or oleic acid content, were not significant.
Desiccation with Paraquat allows advanced harvest without yield losses or modifications in seed
composition. The deterioration of desiccated seeds was lower and independent from oil and
oleic acid content.