Articles
THE INFLUENCE OF ORCHARD SYSTEM AND PRUNING SEVERITY ON YIELD, LIGHT INTERCEPTION, CONVERSION EFFICIENCY, PARTITIONING INDEX AND LEAF AREA INDEX
Article number
349_17
Pages
123 – 128
Language
Abstract
An orchard systems trial comparing slender spindle/M.9, Y-trellis/M.26, central leader/M.9/MM.111 and central leader/M.7 ‘Empire’ apple trees was previously reported to have large differences in yield over the first 10 years.
As the orchard matured, the Y/M.26 system continued to yield more than any other system by an average of 38% from year 11 to 14. Yields for the SS/M.9 system were second while the CL/9/111 and CL/M.7 systems had the lowest yield.
Light interception was stable for each system since the 9th year.
The Y/M.26 system intercepted an average of 69% PAR while the other three systems intercepted from 45–50% PAR. A large portion of the differences in yield between systems could be explained by light interception.
Leaf area index was also well correlated with light interception and yield.
The efficiency of converting light energy into fruit was greatest for the Y/M.26 system.
The CL/M.7 system had the lowest efficiency at year 10 but by year 14 had a similar conversion efficiency as the SS/M.9 and CL/9/111 systems which were intermediate.
Partitioning index (yield/unit increase in trunk cross-sectional area) generally matched rootstock efficiency.
The systems using M.9 (SS/M.9 and CL/9/111) had the highest partitioning index while the CL/M.7’s had the lowest partitioning index.
Conversion efficiencies were generally correlated to partitioning index except with the Y/M.26 system which had the highest conversion efficiency but only an intermediate partitioning index.
This was likely the result of a highly efficient training system but only a moderately efficient rootstock.
The efficiency of the Y/M.26 system was reduced when pruning severity was increased by removing from 0 to 4 large limbs.
As pruning severity increased yield was reduced and shoot growth was increased.
Most of the variation in yield between systems (84%) was accounted for by differences in light interception while only 13% of the yield variation was attributable to differences in conversion efficiency.
As the orchard matured, the Y/M.26 system continued to yield more than any other system by an average of 38% from year 11 to 14. Yields for the SS/M.9 system were second while the CL/9/111 and CL/M.7 systems had the lowest yield.
Light interception was stable for each system since the 9th year.
The Y/M.26 system intercepted an average of 69% PAR while the other three systems intercepted from 45–50% PAR. A large portion of the differences in yield between systems could be explained by light interception.
Leaf area index was also well correlated with light interception and yield.
The efficiency of converting light energy into fruit was greatest for the Y/M.26 system.
The CL/M.7 system had the lowest efficiency at year 10 but by year 14 had a similar conversion efficiency as the SS/M.9 and CL/9/111 systems which were intermediate.
Partitioning index (yield/unit increase in trunk cross-sectional area) generally matched rootstock efficiency.
The systems using M.9 (SS/M.9 and CL/9/111) had the highest partitioning index while the CL/M.7’s had the lowest partitioning index.
Conversion efficiencies were generally correlated to partitioning index except with the Y/M.26 system which had the highest conversion efficiency but only an intermediate partitioning index.
This was likely the result of a highly efficient training system but only a moderately efficient rootstock.
The efficiency of the Y/M.26 system was reduced when pruning severity was increased by removing from 0 to 4 large limbs.
As pruning severity increased yield was reduced and shoot growth was increased.
Most of the variation in yield between systems (84%) was accounted for by differences in light interception while only 13% of the yield variation was attributable to differences in conversion efficiency.
Authors
T. L. Robinson, J. Wünsche, A. Lakso
Keywords
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