Correlations between the germination capacity and selected physical properties of cultivated radish seeds.

Relationships between the physical properties of seed and their germination capacity and energy is an important consideration for separating seeds of the highest or lowest quality. The objective of this study was to determine the correlations between the selected aerodynamic, geometric, frictional and mass parameters of cultivated radish (Raphanus sativus L.) seeds and their germination capacity for the purpose of improving seed quality. The parameters were determined for graded and discarded radish seeds and impurities were separated by a gravity separator. A germination test was performed, its results were verified every 12 hours, and the germination rate index was determined. A statistical analysis revealed that germinated and non-germinated seeds from the graded fraction did not differ significantly. In the discarded fraction, germinated seeds were characterized by higher terminal velocity (by approx. 10%), thickness (by approx. 9%) and mass (by approx. 26%) in comparison with non-germinated seeds. Significant positive correlations were noted between the germination time vs terminal velocity and mass of discarded seeds. Thus, the separation of radish seeds should take place in two stages using a gravity separator and a pneumatic separator. A vertical stream of air with the speed of approx. 8 m s -1 allows recovery of around 37% of discarded seeds that contain approx. 86% of healthy germs. The resulting seed mixture is characterized by greater germination energy and capacity than the seed fraction graded on a gravity separator only.