The priority of transplantation in different sowing dates compare to direct sowing on yield and some physiological characteristics of sugar beet (Beta vulgaris)

Sugar beet is one of the major industrial crops that has a major contribution to sugar production worldwide as well as in Iran. Suitable economic performance in sugar beet is dependent on proper vegetation growth in early growing season and appropriate allocation and distribution of assimilates to the roots, therefore, the time of cultivation of this plant will be important. The growth of sugar beet can be accelerated by planting in the transfer container and transferring it to the main land at a time when the risk of late winter and early spring cold and the problem of water scarcity are removed. Considering the economic importance of sugar beet, especially in Khorasan Razavi province, and adapting this plant for cultivation in Mashhad area, this study was carried out to determine the most suitable planting date and types of transplanting.

This experiment was conducted in research farm of the Faculty of Agriculture, Ferdowsi University of Mashhad in 2017-2018 growing season. The experiment was carried out in a randomized complete block design with 3 replications and 6 treatments. Treatments included: Direct planting in 11 April, Direct planting in 22 May, transplanting with leaves in 5 June, transplantation without leaves in 5 June, transplantation with leaves in 15 June and Transplanting without leaves in 15 June. Sampling and harvesting operations were carried out in late November. Measured indices included root dry matter percentage, root yield (RY), sugar content (SC), sodium content (NA), potassium (K), nitrogen (N), root Alkalinity (ALC), white sugar content (WSC), extraction coefficient sugar (ECS), molasses content (MS), water use efficiency (WUE) and water productivity (WP).

The highest sugar content was obtained in direct planting in 22 May (12.55%) but no significant difference was observed with other treatments. Amongst anti-quality traits, direct planting in 11 April contained highest sodium concentration, also the highest potassium content was observed in leafless transplanting in 5 June. The highest root nitrogen content and alkalinity were obtained in direct planting in 11 April. The highest white sugar content (%) and sugar extraction coefficient (%) were obtained in transplanting with leaves in 15 June treatment. The highest root yield (90.7 t. ha-1) and white sugar yield (5.96 t. ha-1) was obtained in transplanting with leaves in 5 June treatment. The results showed that the highest water use efficiency and water productivity were recorded in transplanting without leaves in 15 June and the lowest were observed in direct planting treatments.

The results of this study showed that transplantation of sugar beet in proper time can increase root and white sugar yield and also improve water use efficiency and economic water productivity in Mashhad conditions. In addition, direct seed sowing in 11th April and transplanting with leaves in 5 June showed the highest root and white sugar yield. Therefore, it may be suggested that sugar beet transplanting with leaves extended in sugar beet production areas after arrangement of local trails.