Quantitative and qualitative analysis of sugar beet cultivars: Implications for harvest date stability

Abstract This research assessed the quantitative and qualitative reactions of commercially grown sugar beets to four different harvest dates and their yield stability. The study followed a split-plot design within a randomized complete block design over three years. The main plot involved four harvest dates: August 13 (HD 1 ), September 7 (HD 2 ), October 3 (HD 3 ), and November 12 (HD 4 ), while the subplot involved 10 sugar beet cultivars. HD 4 resulted in 84.95%, 30.12% and 23.73% higher root yield compared to HD 1 , HD 2 and HD 3 , respectively. The best sugar content, white sugar content, and extraction coefficient of sugar were observed from HD 3 in the third year. Maximum sugar yield, maximum white sugar yield, and minimum molasses sugar percentage were associated with HD 4 in the third year. Perfekta displayed the highest root yield, sugar yield, white sugar content, white sugar yield, extraction coefficient of sugar, and minimum molasses sugar percentage in the third year. Additive main effect and multiplicative interaction analysis based on white sugar yield indicated that genotype and environment's additive effects, as well as the genotype- environment interaction, significantly contributed to 3.05%, 32.10%, and 8.31% of the total data variance, respectively. Arta and Arya were identified as stable for white sugar yield based on all additive main effect and multiplicative interaction stability indices and demonstrated high general adaptability in all regions. Additionally, Perfekta exhibited high specific adaptability in eight out of 12 tested environments. According to the multi-trait stability index, Perfekta and Shokoufa were recognized as stable and superior across all measured traits.