The Effect of Dwarfing Interstocks on Vegetative Growth, Fruit Quality and Ionome Nutrition of ‘Fuji’ Apple Cultivar ‘Tianhong 2’—A One-Year Study

Dwarfing interstocks play an essential role in determining the performance of fruit trees. SH40, Jizhen 1, and Jizhen 2 are widely used dwarfing interstocks in Hebei Province, China. This study examined the influence of these three dwarfing interstocks on vegetative growth, fruit quality and yield, and leaf and fruit macro- (N, P, K, Ca, and Mg) and micro- (Fe, Zn, Cu, Mn, and B) element contents for ‘Tianhong 2’. Five-year-old ‘Fuji’ apple cultivar, ‘Tianhong 2’, on ‘Malus. Robusta’ rootstock, was cultivated with SH40, Jizhen 1, or Jizhen2 dwarfing rootstock as an interstock bridge. Jizhen 1 and 2 had more branches and a higher proportion of short branches than SH40. Jizhen 2 had a higher yield, good fruit quality, and higher leaf macro- (N, P, K, and Ca) and micro-element (Fe, Zn, Cu, Mn, and B) contents; Jizhen 1 had the highest leaf Mg content in the growing period. The fruit N, P, K, Fe, Zn, Cu, Mn, and B contents were higher in Jizhen 2. SH40 had the highest fruit Ca content. There were significant correlations in nutrient elements between leaves and fruit in June and July. Comprehensive analysis showed that Tianhong 2 had moderate tree vigor, high yield, good fruit quality, and high mineral element content in leaves and fruits when Jizhen 2 was used as an interstock.