Growth, Yield, Survival, and Leaf Nutrient Concentrations of Plums on Various Rootstocks

Abstract

Effects of seedling rootstocks Lovell, Halford, Nemaguard, and Nemared and asexually propagated root-stocks St. Julien A and Pixy on tree growth, yield, survival and leaf nutrient concentration of 2 plum cultivars was studied. Yields did not differ among rootstocks for 'AU-Producer' or 'AU-Amber'. Cumulative yield efficiency (CYE) did not differ among rootstocks grafted with 'AU-Amber,' but was significantly lower for Pixy rootstock grafted with 'AU-Producer' compared to Lovell, Halford, Nemaguard, Nemared and St. Julien root-stocks. St. Julien and Pixy dwarfed scions, resulting in smaller canopy widths and trunk cross-sectional areas (TCA). Their effect on bloom dates was inconsistent, delaying bloom in some years but not in others. The only rootstock-by-year interactions for foliar nutrient levels were for Mn, Fe, and B with 'A U-Producer'. Nutrient levels and multiple regression results indicated that Mg was a positive predictor for canopy width and TCA while Zn and Mn were negatively related to TCA. Attempts to predict tree survival rates in 1994 and 1995 with 1993 and 1994 leaf nutrient levels, respectively, indicated that survival in 1994 was positively predicted with K and negatively with Mn with an R ²of 0.143. There was no predicted model for 1995 survival based on 1994 nutrient data. Survival in 1995 was negatively predicted with 1995 Zn levels with an R ²of 0.277.