Evaluation of percentage and degree of inulin polymerization and yield in 15 cultivars and accessions of chicory (Cichorium intybus L.) in northern plains of Iran

To evaluate the percentage and degree of polymerization and yield of inulin, and also root fresh yield of 13 native accessions and two imported cultivars of chicory (Cichorium intybus L.), an experiment was conducted using randomized complete block design with three replications in Khoshkedaran Research Station of Mazandaran province, Iran, in three consecutive years (2016-2018). The roots were harvested at the end of the rosette stage in the second year of cultivation, then weighed and relevant calculations were performed. Samples were extracted by using aqueous extraction method, and their total sugar content and reducing sugar and the percentage and degree of polymerization of inulin were calculated. Means comparison showed that accessions "Rasht" and "Chamestan" and imported cultivar "Selenite" had the highest percentage of inulin (15.8, 13.9, and 14.3%, respectively) among the chicory genotypes. Findings showed that cultivar "Selenite" and accession "Tonekabon" were more superior to other genotypes in terms of fresh root yield and inulin and ranked first (35.458 t ha-1 fresh root and 2818.99 kg ha-1 inulin yield) and second (12.692 t ha-1 fresh root and 807.5 kg ha-1 inulin yield), respectively. In addition, "Selenite" and "Tonekabon" had good stability in terms of percentage and degree of inulin polymerization in two years of research and were found to be more suitable for the western region of Mazandaran province than other genotypes.