Seed Coating: A Sustainable Way to Compensate for the Loss of Plant Number Per Unit Area in Sugar Beet Fields

Abstract

Different methods of sugar beet seed threshing have been used to improve the seed cultivation value. Two types of processing are common, including ordinary processing (seed size of 3.00–4.75 mm round sieve, coating with Gaucho insecticide) and special processing (seed size of 4.00–4.5 mm round sieve, and above 2.2 mm long sieve, coating with Cruiser insecticide). The present study was conducted to evaluate the effects of seed processing and plant density on quantitative and qualitative traits of sugar beet as a factorial experiment in a randomized complete block design with four replications in the crop year 2017–2018 in two regions of Karaj and Kermanshah. The first factor included the processing methods were ‘Shokoufa’ seeds with ordinary threshing and coating with Gaucho (a₁) and Cruiser (a₂), ‘Shokoufa’ seeds with special threshing and coating with Gaucho (a₃) and Cruiser (a₄) and seeds of cultivar F20909, and the second factor included the final plant density including 7, 10, and 13 plants per m². The highest contents of impure (16.99%) and white sugar (8.23 t ha⁻¹) and extraction coefficient of sugar (82.43%), and the lowest amounts of molasses (2.30%), harmful nitrogen (2.34 meq 100 g⁻¹ beet), and potassium (4.97 meq 100 g⁻¹ beet) were observed in F20909. Root yield, impure sugar yield, and white sugar significantly increased with increasing plant density. Regarding different areas of sugar beet cultivation, it was found that plants grown in Karaj had higher root yield (69.19 t ha⁻¹), impure sugar (10.28 t ha⁻¹), white sugar (7.58 t ha⁻¹), harmful nitrogen (3.45 meq 100 g⁻¹ beet), potassium (6.32 meq 100 g⁻¹ beet), sodium (3.24 meq 100 g⁻¹ beet), and molasses sugar (3.30%), while plants grown in Kermanshah had higher white and impure sugar content (16.55 and 14.14%), alkalinity (3.29), and extraction coefficient of sugar (84.84%).