ISHS Acta Horticulturae 160: III International Symposium on Research and Development on Orchard and Plantation Systems
PRODUCTIVITY AND FRUIT QUALITY OF FOUR APPLE CULTIVARS ON THREE DIFFERENT ROOTSTOCKS AND AT DIFFERENT PLANTING DENSITIES |
| Authors: | R. Ogata, K. Goto, T. Kunisawa, R. Harada |
| Abstract:
Cultivars Tsugaru, Red King Delicious (RK), Jonagold (JG) and Fuji apples, each on M.27, M.9a and M.26 rootstocks, were planted in 1977 in a randomised block experiment at the Fukushima Fruit Tree Experiment Station. Each scion/rootstock combination was represented by 3 replications of 8 trees. Tree spacing for cvs Tsugaru, RK and JG was 4 x 2 m, trees of cv Fuji were in rows 4 m apart with a within-row spacing of 1.25, 2.00 or 2.75 m. As expected, trees of all cvs on M.27 were smaller than those on M.9a or M.26. The order of tree size between those extremes varied with the scion cultivars. Fuji on M.26 and on M.9a were almost identical in size. JG/M.9a was slightly but not significantly larger than JG/M.26, and Fuji/M.9a was slightly but not significantly smaller than Fuji/M.26. Over the first 7 years the greatest yields of Tsugaru and Fuji were from trees on M.26 and of Jonagold and Red King Delicious from trees on M.9a. Yields of Tsugaru, RK and JG on M.27 had begun to flatten after the fifth season, but yields of Fuji continued to increase. Fruits from all cvs on M.27 were consistently smaller than those of M.9a or M.26, but the soluble solids contents of fruits from all cvs on M.27 were slightly higher than those on M.9a or M.26. For cv Fuji, there was no significant effect of spacing on mean girth of trees on M.27, but the mean girth of trees on M.9a or M.26 at the closest spacing was significantly smaller than the mean of the wider spacings. The more trees there are per ha the smaller the yield per tree. Per ha the loss in yield per tree was more or less compensated by the number of trees. The differences are more striking when the data are expressed as yield per square centimeter of trunk cross-sectional area, reflecting potential differences in yield per ha given the closer spacings possible with less vigorous stocks. At the closest spacing, however, branches or twigs of the trees on M.9a and M.26 began to cross each other within the row in the fourth growing season, which led to an increase in the percentages of poor coloured or small fruits, and made it difficult to manage the trees in later years. | |
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