Polymer utilization in sugar beet seed coating

This study aimed at determining the effect of domestic synthesized polymer on germination and growth of sugar beet seedling in laboratory, greenhouse, and field. The study was conducted based on randomized complete block design with four replications at Sugar Beet Seed Institute, Karaj, Iran in 2010-2012. The treatments were uncoated (control) and coated seed with foreign polymer, and also seven domestic polymer doses (0.5-3.5 g/100 g seeds). The viability, leaflet and rootlet dry weight were measured in the laboratory, vigor was measured in the greenhouse, and germination rate together with quantitative and qualitative traits were measured in the field. To determine the effect of polymer coating on seed deterioration and germination rate, sampling was performed for seven times. For seed vigor, sampling was performed up to 541 days after coating for six times. No significant difference was observed among the studied treatments for seed germination rate, abnormal germination percentage in the laboratory and seed vigor in the greenhouse. However, polymer coating had significant (P<0.01) effect on leaflet and rootlet dry weights so that the highest rootlet dry weight (4.306 g) was obtained in 0.5 g/100 g seeds treatment compared to the uncoated seed with 3.741 g. The highest leaflet dry weight (1.2-584.463 g) was observed in uncoated seed, and coated seed with domestic and foreign polymers with 0.5-1.0 g/100 g seeds ratio. Seed deterioration showed that 141 days after seed processing, germination rate was significantly (P<0.01) decreased and abnormal germination percentage was increased (P<0.01). Nevertheless, these changes were similar for uncoated seeds and coated seeds with polymer. The effect of time on seed vigor was significant (P<0.01) and the highest seed vigor percentage (33.36-79.81) was found in domestic synthesized polymer with 1.0-1.5 g/100 g seeds. The lack of the significant influence of the studied treatments on plant density, before and after thinning and also at harvest, show that seed coating had no influence on plant establishment in the field. Based on the field results, it is recommended to apply domestic polymer for seed coating to not only maintain crop performance but also to manage the cost. The results of this study showed that application of domestic synthesized polymer at the rate of 1.0-1.5 g/100 g seeds is suitable for the increase of seed vigor in seed processing.