Abstract: Fragaria × ananassa‘Yuexin’is a new strawberry cultivar selected by our group. The Yuexin mutant is a stable somaclonal variation from Yuexin found in the regeneration plants differentiated stem apex. The results showed that there were no significant differences between Yuexin and its mutant in plant morphology，onset of blooming and fruit，onset of fruit ripening，average fruit weight and plant yield，fruit shape and fruit flavor，etc. However，compared with Yuexin，the pricarp of its mutant was brighter with higher L* and lower a*，greater H and less CIRG index，and the mutant had colorless pulp. The total content of anthocyanin in the mutant was only 13.2% of Yuexin，of which the largest difference was the content of geranium-3-O-glucoside（Pg3G），the content of Pg3G in the mutant was only 12.9% of Yuexin. The expression levels of the structural genes FaF3H，FaCHS，FaDFR，FaANS，FaCHI and Fa3GT involved in the anthocyanin synthesis pathway were significantly reduced in the mutant fruit，indicating the possible direct factors that resulting in the lower levels of anthocyanin in the mutant. The expression levels of the transcription factors FaMYB10 and FaMYB1 in Yuexin mutant were decreased significantly，and the eigenvector absolute values of FaMYB10 in several principal components were significantly higher than other factors，which further proved that MYB10 was one of the main regulating factors involved in flavonoids/phenylpropanoids of anthocyanin pathway during strawberry maturation. KASP analysis using leaf genomic DNA showed that there was no genotype differentiation between Yuexin and its mutant based on 74 primer pairs amplification. The results in this study confirmed that the Yuexin mutant was genetically stable，and the mutation caused the significant decrease in the expression of key genes involved in the regulation of anthocyanin synthesis，resulting in decreasing of anthocyanin accumulation and reducing fruit coloration.

Key words: strawberry, tissue culture, somaclonal mutation, anthocyanin, fruit quality