Wax bayberry is a suitable rootstock for Chinese red bayberry cultivated in saline-alkali soil

Wax bayberry or wax myrtle, Morella cerifera L., (MC) is a member of the Myricaceae family and belongs to the same genus as Chinese red bayberry (Morella rubra) (MR). It is an evergreen shrub native to Pennsylvania, USA, and is resistant to saline-alkali stress. China has a large area of saline-alkali soil in the south-eastern coastal regions, and this study aimed to evaluate the suitability of MR cv 'Biqi' grafting on MC for cultivation on saline soil. This MC rootstock tolerated stress in soil with high sodium, magnesium and calcium concentrations with no toxicity symptoms. Trees of cv 'Biqi' grafted on MC grew normally in saline-alkali soil, with dark green leaves, high chlorophyll content and healthy appearance, while the trees grafted on MR suffered severe chlorosis in saline alkali soil. The average fruit weight of the 'Biqi' cultivar grafted on MC in saline alkali soil steadily increased over the 2016-2018 period, and were larger in size and higher in sucrose and citric acid content than those on the MR rootstock grown in either coastal or mountainous areas. The bayberry grafted on MC rootstock also tended to flower and set fruit 1-2 years earlier than that grafted on MR rootstock. High compatibility between the scion (MR) and rootstock (MC) was observed in the microscopic section of the grafting interface. Thus, wax bayberry was considered an effective rootstock for the cultivation of red bayberry in saline-alkali soils.