ISHS Acta Horticulturae 479: IX International Asparagus Symposium
INFLUENCE OF TIME OF SPEAR HARVEST ON ROOT SYSTEM RESOURCES DURING THE ANNUAL GROWTH CYCLE OF ASPARAGUS |
| Authors: | D.R. Wilson, S.M. Sinton, C.E. Wright |
| Abstract:
Spear yield in asparagus depends on resource availability in the storage root system during harvest, particularly the number of buds and the amount of soluble carbohydrate (CHO). Both fluctuate during the crop's annual growth cycle, in association with sequences of fern and spear growth. We studied the fluctuations during two annual growth cycles in which treatments were applied to alter the sequences, and therefore the amounts of fern and spear growth, in established crops. The treatments were an undisturbed annual cycle (no spear harvest), and spring, extended spring, summer and autumn spear harvests. There were large differences in the amount of fern growth among the treatments. Bud number did not limit spear yield except in the summer harvest treatment. This treatment severely depleted the root system and produced a very low yield. The treatments caused large variations in the pattern of CHO accumulation and depletion, and therefore the spear yield in the current and following seasons. The spring harvest treatment produced good spear yields in both seasons and also achieved the best balance between accumulation and depletion of resources. Although it had much less fern growth than the undisturbed treatment, it ended each season with a recharged and growing root system. In contrast, the extended spring and autumn treatments produced lower spear yields and ended each season with partly depleted root systems. | |
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