ISHS Acta Horticulturae 146: International Workshop on Controlling Vigor in Fruit Trees
A COMPARISON OF THE DWARFING CHARACTER AND WATER RELATIONS OF FIVE APPLE ROOTSTOCKS |
| Authors: | W. C. Olien, Alan N. Lakso |
| Abstract:
Water relations of 6-year-old 'Empire' apple trees (Malus domestica Borkh.) were compared on the rootstocks M9, M26, M7, MM106, and MM104 (from most to least dwarfing) in July, with high soil moisture. Diurnal changes in stem water potential showed that the most dwarfing stocks (M9, M26) were under more stress at mid-day than the other stocks. There were no differences among rootstocks in transpiration and stomatal conductance through the day and no differences in stem potential in the early morning or evening. Gradient in stem potential, from the base to exterior of the canopy, did not differ between M9 and MM104 at mid-day, even though the mean stem potentials were different. Lower stem potential in the dwarfing M9 stock, compared to the vigorous MM104, appeared to be due to greater root resistance, rather than a rootstock effect on ability of the scion to conduct water. | |
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