Determination of the effect of different harvesting times on yield, yield components and technological characteristics of sugar beet (beta vulgaris var. saccharifera L.) varieties

This study was conducted in 2023 and 2024 in Erciş district of Van province to determine the effects of different harvest times on yield, yield components, and technological traits in sugar beet (Beta vulgaris var. saccharifera L.) varieties. The experiment was carried out using a "Split Plots in Randomized Blocks Trial Design" with three replications. Cultivars (Bernache, Kuzgun, Allanya, Terranova, Tuna) were assigned to main plots, and harvest times (September 25, October 10, October 25, November 10 and November 25) were assigned to subplots. Parameters such as root-stem yield, head+leaf yield, stem diameter, stem length, forked stem ratio, head+leaf weight, stem weight, leaf area, sugar yield, biomass yield, harvest index, sugar content, α-amino nitrogen, ash percentage, juice purity, dry matter content, and mark presence were investigated. As a result of the study, when the variance analysis of the average values of the trial years and the combined years was examined, statistically significant differences were found between the varieties on all parameters except for the sugar content, juice purity, dry matter content for 2024, and the brand presence ratio for the years combined with 2023 and 2024. Furthermore, the effect of harvests in different periods on all parameters was also found to be statistically significant. The highest root and shoot yields of 11470.42 kg/da and 11207.74 kg/da were obtained in the 2023 and 2024 trial years, respectively. The highest root and shoot yields in both trial years, 13009.26 and 12705.09 kg/da, respectively, were obtained from the Terranova variety during the November 25 harvest period. It was determined that root and shoot yield increases with the delay in sugar beet harvest. In terms of sugar yield, the highest value (2679.86 kg/da) was obtained from the November 25 harvest period of the Terranova variety in the 2023 trial year, while the highest value (2578.37 kg/da) was obtained from the November 25 harvest period of the Tuna variety in the 2024 trial year. However, according to the combined year average values, the highest sugar yield of 2537.01 kg/da was obtained from the November 25 harvest date of the Terranova variety. It was determined that root-stem yield and sugar yield increased with delays in harvest times, while early harvests resulted in decreases in root-stem and sugar yield. Additionally, when the pairwise relationships (correlation analysis) among the traits examined in the study were evaluated, a statistically significant and positive correlation was found at the 1% level between root-stem yield and parameters such as stem diameter, stem height, ratio of branched stems, stem weight, sugar yield, biomass yield, harvest index, sugar content, and dry matter content, and at the 5% level with juice purity. Keywords: Beta vulgaris var. saccharifera L., Harvest time, Quality, Sugar beet, Variety, Yield