关键词: 油菜, 种子丸粒化, 膨润土, 桉木粉, 种子萌发

Abstract: The aims were to screen out suitable pelleting formulas for rapeseed（Brassica napus L.）seeds，and investigate the relationship between the physical properties of fillers and the quality of pelleted seeds as well as their germination. The study used bentonite（B）and eucalyptus sawdust（E）as fillers，with mass ratios of 10∶0，9∶1，8∶2，7∶3，6∶4，5∶5，4∶6，3∶7，2∶8，1∶9，and 0∶10，respectively.Eleven physical property indicators of the fillers were measured，and five quality indicators and eight germination indicators of rapeseed pelleted seeds were detected. Cluster analysis and correlation analysis were used to explore the effects of the bentonite and eucalyptus sawdust ratios on the physical properties of the fillers，the quality of the pelleted seeds，and the germination of the pelleted seeds，as well as the relationship between them. The results showed that the indicators such as the Carr index，porosity，Hausner ratio，median particle size，particle size distribution range，and water solubility of eucalyptus sawdust were all higher than those of bentonite. With the increase of the proportion of eucalyptus sawdust，the median particle size，particle size distribution range，and water solubility of the fillers significantly increased，while the bulk density and tapped density significantly decreased，with other indicators showing a multi⁃peak trend. The compressive strength of the pelleted seeds increased first and then decreased with the increase of the proportion of eucalyptus sawdust，with B4E6 treatment（i.e.，B∶E = 4∶6；hereinafter，similar notation applied）reaching the highest value of 6. 81 N.There was no significant difference in germination rate between the B8E2，B7E3，and B6E4 treatments and the bare seeds. Among them，the B6E4 treatment had a better comprehensive performance，with average germination rate of 88%，vitality index of 1.20，average root length of 5.42 cm，average shoot length of 2.53 cm，average dry weight of seedlings（five）of 0.038 7 g，and relatively better pelleted seeds quality indicators：compressive strength of 5.98 N，single seed rate of 99%，and 100% seed rate. Correlation analysis showed that germination potential and germination index were significantly positively correlated with median particle size，particle size distribution range，and water solubility，and significantly negatively correlated with bulk density and tapped density.In summary，the physical properties of the fillers（bulk density，tapped density，median particle size，particle size distribution range，and water solubility）significantly affect the quality and germination of the pelleted seeds，and B6E4 was selected as the optimal pelleting formula for rapeseed seeds.

Key words: Rapeseed, Seed pelleting, Bentonite, Eucalyptus wood powder, Seed germination