Abstract:In order to explore the effects of S-ABA, methyl jasmonate (MeJA), and coronarin (COR) plant growth regulators on the color and quality of ‘Flame Seedless’ grapes, and to screen out the best measure to promote the coloration and quality of ‘Flame Seedless’ grapes. Three treatments of 100 mg/L S-ABA, 60 mg/L MeJA, and 2000 times dilution of COR were set up, and the ears were dipped at the early stage of color change and sampled seven times from the treatment to the mature stage. The berry weight, longitudinal and transverse diameter, and the contents of soluble solids, total acid, anthocyanin, chlorophyll, carotenoids, and phenolic compounds were measured and analyzed continuously. The results showed that (1) S-ABA, MeJA, and COR treatments could promote fruit coloration, significantly increase the fruit surface color parameter a* value, and decrease the L* value, b* value, and h°; The contents of anthocyanin in the three treatments were significantly increased by 62.84%, 58.72%, and 23.98%, respectively. (2) S-ABA, MeJA, and COR treatments could improve fruit quality. Compared with the control, the soluble solids content increased by 9.17%, 7.45%, and 9.74%, the total acid content decreased by 6.81%, 4.14%, and 9.25%, and the soluble solids to total acid ratio increased by 17.90%, 12.16%, and 20.82%, respectively. (3) S-ABA, MeJA, and COR treatments increased the berry weight, longitudinal diameter, and transverse diameter, increased flavonoids, flavonoid, flavanols, and total phenols content, and decreased total acid and tannins content, but had no effect on fruit shape index and pedicel endurable pulling force. (4) Anthocyanin content was positively correlated with soluble solid content, a* value and CIRG value (P<0.05), but negatively correlated with h°, L* value, b* value, total acid content and chlorophyll content; It was negatively correlated with L* value, b* value, h° and total acid content.; the anthocyanin content was positively correlated with total phenols content, but negatively correlated with flavonoids content, flavanols content, and flavonoid content. The results showed that 100 mg/L S-ABA and 2000 times dilution in the early stage of color transformation could effectively promote the color of ‘flame seedless’ grapes and improve fruit quality. The a* value and CIRG value of fruit color were positively correlated with anthocyanin content (0.80, 0.70), which could be used as a reference index for quantifying fruit coloration.