| Abstract: To investigate the effects of different foliar fertilizers on the fruit quality of 'Yanfu 3' apple (Malus domestica Yanfu), and to provide some theoretical basis for improving its fruit quality. 6-year-old 'Yanfu 3' apples in Ning County, Qingyang, Gansu Province were selected as the test material, we set the following conditions: Leaf Xumi amino acid enzyme solution (T1), fluid calcium (T2), sugar alcohol boron (T3), potassium xanthate of mineral origin (T4), organosilicon + enzyme calcium (T5), Leaf Xumi + fluid calcium + sugar alcohol boron (T6), Leaf Xumi + fluid calcium + sugar alcohol boron (T7), Leaf Xumi + fluid calcium + organosilicon + organosilicon (T7), Ye Xiumei + fluid calcium + sugar alcohol boron + organosilicon + mineral potassium xanthate (T8), brassicas (T9), brassicas + bud double promotion (T10), Le Pure medium amount of elements of water-soluble fertilizers + organosilicon (T11), sodium compound nitrophenol (T12), aminofresh fat (T13), sodium compound nitrophenol + aminofresh fat (T14), sugar + enzyme + urea (T15), sodium compound nitrophenol + aminoflour + Leconium + sugar + enzyme + urea (T16), etc. A total of 16 foliar fertilizer treatments were applied with water spray as the control (CK), and the indicators related to fruit quality were measured in different treatments and periods. The results showed that spraying foliar fertilizers could obviously increase the single fruit weight, fruit longitudinal and transverse diameter and fruit shape index, of which the effects of T12 and T16 treatments were the most obvious; T14 treatment had the best effect on improving fruit hardness, while T12 treatment had a greater effect on soluble solids content. At the same time, different foliar fertilizer treatments had a greater effect on the coloring of the fruits of 'Yanfu 3'. Especially, the peel color a value, flavonoid and anthocyanin contents were significantly increased under T11 treatment. Both soluble sugar content and soluble protein were best in T14 treatment. The highest fructose and sucrose contents were in T11 and T12 treatments, respectively. Therefore, comprehensive analysis revealed that T11, T12 and T14 treatments had the most significant effect on improving fruit quality. The spraying of foliar fertilizers had an important effect on the aroma substances aldehydes, alcohols, acids, esters, ketones and olefins in the fruit. In this study, aldehydes, esters and alcohols were the main types of aroma substances in 'Yanfu 3', as well as hexyl acetate, n-hexanal and 2-hexenal were the characteristic aroma components of 'Yanfu 3' fruits. In summary, T11, T12 and T14 treatments were more effective in improving the fruit quality of 'Yanfu 3' apples in the Loess Plateau region. |