Castor bean seeds have slow and irregular germination that frequently results in irregular seedling emergence in the field. This fact has been attributed to their probable impermeability to water. The objective of this study was to evaluate the effect of pre-germination treatments on seed performance. Five seed lots, AL-Guarany cultivar, were submitted to the following treatments: control (untreated seeds), scarification with sandpaper, caruncle removal, tegument removal, immersion in water for 12 and 24h, caruncle removal + immersion in water for 12 and 24h, scarification with sandpaper + immersion in water for 12 and 24h, germination at 10ºC/7 days and at 25ºC/5 days, germination at 10ºC/7 days and at 30ºC/5 days, accelerated aging at 41ºC/48h and 100% RH. After each treatment, with exception of the germination at 10ºC, the seeds were submitted to the germination test, at 25ºC. Counts were performed at 7 and 14 days after sowing. In general, all the pre-germination treatments contributed to increasing the germination percentage of castor bean seeds in relation to the control. The most efficient treatments to speed up germination were scarification with sandpaper and caruncle or tegument removal. However, considering the practical application, scarification can be recommended to increase the percentage and speed of seed germination.
Ricinus communis L.; speed of germination; scarification
