Determining the optimum planting and harvesting date in selected cultivars of sugar beet in Ilam climatic conditions (autumn planting).

In order to compare and determine the potential, and compatibility level of different sugar beet (Beta vulgaris L.) cultivars at different planting and harvest dates, a two years (2014-16) trial was conducted in Etka Dehloran field. In the first and second year, the trial was performed in split plot- and split-split plot based on randomized complete block design, respectively with three replications. In the first year, the main plots consisted of 15 cultivars and the planting date of 2nd October 2014 and the split plots included harvest dates of 14th and 30th April 2015. In the second year, the main plots consisted of five selected cultivars from first year trial, three planting dates (16th September, 1st and 16th October) in split plots, and three harvest dates (14th and 30th April and 14th May) in split split plots. The evaluated traits were root yield, sugar content, sugar yield, white sugar yield, Na and K content and extraction coefficient of sugar. Results of analysis of variance in the first year showed that there was a significant difference between the cultivars in terms of studied traits. According to the evaluated traits, among 15 studied cultivars and based on bolting resistance, Antek, Azaba, Silvetta, Spartak, and Sharif were superior to other cultivars; therefore, these cultivars were selected for continuous screening in the second year of the trial. In the second year, there was a significant difference between cultivars in terms of studied traits, so that the highest root yield was related to Sharif cultivar (83.32 tha-1). The highest sugar content (17.29%) and extraction coefficient of sugar (14.68%) were related to Silvata cultivar.