Effect of desiccation moment on 1000-seed weight in sunflower

The experiment was carried out at Rimski Šančevi (Serbia) during 2009 in order to investigate the effect of chemical desiccation on 1000-seed weight in three sunflower lines, and to determine the optimal moment for performing desiccation. Desiccation was carried out with herbicide Reglone forte (2 l/ha) repeatedly each 7 days, starting from the end of flowering to harvest maturity. All three lines showed highly significant differences in weight of 1000 seeds, and a highly significant effect of a moment of desiccation on 1000-seed weight. The lowest weight was determined when the treatment was performed 7 days after flowering and the highest when the treatment was performed 28 days after flowering with seed moisture content of 22.23%. The results show that this is the optimal time for chemical desiccation. There was no significant difference in 1000-seed weight between the treatment 28 days after flowering and the following treatments, suggesting that seed filling had been finished.