Hybrid sunflower seed yield, composition and deterioration after chemical desiccation

Abstract

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