Abstract Spinach (Spinacia oleracea) is one of the most important leafy vegetables which consumed as fresh and processed, and known for its high yield and rapid growth. It is native to Iran and holds significant nutritional value. Due to its long history of cultivation in Iran, different and valuable populations can be found. Therefore, the collection, preservation, maintenance, and eva‎luation of the genetic traits of this vital vegetable are important. Bolting is an involuntary physiological phenomenon that leads to premature flowering and subsequently quality loss in spinach. Thus, it is crucial to conduct a detailed examination of native populations and compare them with foreign populations to eva‎luate bolting trait. Accordingly, this experiment aimed to identify single nucleotide polymorphisms (SNPs) in genes and promoter regions associated with flowering of 10 spinach genotypes. For this purpose, seeds of early and late bolting genotypes were collected and cultivated in the greenhouse of Isfahan University of Technology during the 2021-2022 years. The spinach genotypes included nine native populations and one non-native population (Viroflay). After eva‎luating the genes associated with bolting, three genes, along with a promoter region, were selected for the eva‎luation. Suitable primers were designed, and the target regions were analyzed for nucleotide diversity. The results of Tajima's D test for the evolutionary analysis of SPO04942, SPO04967 and SPO05293 genes indicated that these genes were under balanced selection and not significantly affected by selective pressure. Therefore, they can be considered as suitable candidates for genetic manipulation and classical breeding methods, unaffected by selective pressure, to produce late bolting varieties. Phylogenetic analysis demonstrated that almost all the genes eva‎luated in this research are capable of distinguishing between early and late bolting genotypes, serving as suitable markers for the bolting trait. These results provide a comprehensive understanding of the molecular mechanisms of bolting in spinach and are valuable for the production of various compatible spinach germplasms suited for different regions. Keywords: Spinach, Bolting, Single nucleotide polymorphism identification, Sanger sequencing, Tajima's D test.

ابوذر سورني , رحيم مهرابي

مجيد طالبي , اقافخر ميرلوحي فلاورجاني