Acknowledgments
We are grateful to the staff at HortResearch, Motueka, New Zealand for their assistance and support, Michael Moss, Motueka, New Zealand for the use of his orchard, Jens Wünsche and John Palmer for supervision and MDPI for the invite to this contribution and waiving the APC and Ligia Hent for editorial guidance.
The manuscript was finished under covid-19 including access restrictions to university services.
Figure 1.
Apple trees of cv. Pacific Rose on MM 106 (a) without (left) and (b) with reflective mulch (right) at HortResearch, Motueka (NZ).
Figure 1.
Apple trees of cv. Pacific Rose on MM 106 (a) without (left) and (b) with reflective mulch (right) at HortResearch, Motueka (NZ).
Figure 2.
Temperature curve in March and April at HortResearch, Motueka, New Zealand, during the experiment- black arrows indicate the dates of laying the reflective material for Fuji (F) and Pacific Rose (PR) and the red arrows for the begin of the harvest (asterisks).
Figure 2.
Temperature curve in March and April at HortResearch, Motueka, New Zealand, during the experiment- black arrows indicate the dates of laying the reflective material for Fuji (F) and Pacific Rose (PR) and the red arrows for the begin of the harvest (asterisks).
Figure 3.
Summation of yield in each pick of cv. Fuji as dependent on the timing of reflective mulch in Motueka, New Zealand, (41° S). (Picks with different letter for the same treatment are statistically different (p < 0.05) (n = 60 fruit per treatment per position)).
Figure 3.
Summation of yield in each pick of cv. Fuji as dependent on the timing of reflective mulch in Motueka, New Zealand, (41° S). (Picks with different letter for the same treatment are statistically different (p < 0.05) (n = 60 fruit per treatment per position)).
Figure 4.
Summation of yield in each pick of cv. Pacific Rose as dependent on the timing of reflective mulch in Motueka, New Zealand, (41° S). (Picks with different letter for the same treatment are statistically different (p < 0.05) (n = 60 fruit per treatment per position)).
Figure 4.
Summation of yield in each pick of cv. Pacific Rose as dependent on the timing of reflective mulch in Motueka, New Zealand, (41° S). (Picks with different letter for the same treatment are statistically different (p < 0.05) (n = 60 fruit per treatment per position)).
Figure 5.
Score values of blush development in cv. Fuji in March as dependent on the timing of reflective mulch (average of fruit from the inside and outside of the tree canopy). (plus SEs; Different letters denote statistical differences within the same date at the p = 0.05 level (n = 80 fruit per treatment per pick.) Arrow indicates day of laying the mulch.
Figure 5.
Score values of blush development in cv. Fuji in March as dependent on the timing of reflective mulch (average of fruit from the inside and outside of the tree canopy). (plus SEs; Different letters denote statistical differences within the same date at the p = 0.05 level (n = 80 fruit per treatment per pick.) Arrow indicates day of laying the mulch.
Figure 6.
Score values of blush development in cv. Pacific Rose in March as dependent on the timing of reflective mulch (average of fruit from the inside and outside of the tree canopy) at Motueka (NZ). (plus SEs; Different letters denote statistical differences within the same date at the p = 0.05 level (n = 80 fruit per treatment per pick.) Arrow indicates day of laying the mulch.
Figure 6.
Score values of blush development in cv. Pacific Rose in March as dependent on the timing of reflective mulch (average of fruit from the inside and outside of the tree canopy) at Motueka (NZ). (plus SEs; Different letters denote statistical differences within the same date at the p = 0.05 level (n = 80 fruit per treatment per pick.) Arrow indicates day of laying the mulch.
Figure 7.
Colour development dependent on fruit position within the tree of cv. Fuji as measured on 15, 22 and 29 March on the inner green side of the fruit as affected by reflective mulch. (Treatments with different letter for the same position of the fruit within the same day are statistically different (p < 0.05) (n = 60 fruit per treatment per position)).
Figure 7.
Colour development dependent on fruit position within the tree of cv. Fuji as measured on 15, 22 and 29 March on the inner green side of the fruit as affected by reflective mulch. (Treatments with different letter for the same position of the fruit within the same day are statistically different (p < 0.05) (n = 60 fruit per treatment per position)).
Figure 8.
Colour development dependent on fruit position within the tree of cv. Fuji as measured on 15, 22 and 29 March on the red side of the fruit as affected by reflective mulch. (Treatments with different letter for the same position of the fruit within the same day are statistically different (p < 0.05) (n = 60 fruit per treatment per position).
Figure 8.
Colour development dependent on fruit position within the tree of cv. Fuji as measured on 15, 22 and 29 March on the red side of the fruit as affected by reflective mulch. (Treatments with different letter for the same position of the fruit within the same day are statistically different (p < 0.05) (n = 60 fruit per treatment per position).
Figure 9.
Colour development dependent on fruit position within the tree of cv. Pacific Rose as measured on 14, 21 and 28 March on the green side of the fruit as affected by reflective mulch spread 4 or 2 weeks prior to anticipated harvest. (Treatments with different letter for the same position of the fruit within the same day are statistically different (p < 0.05) (n = 60 fruit per treatment per position).
Figure 9.
Colour development dependent on fruit position within the tree of cv. Pacific Rose as measured on 14, 21 and 28 March on the green side of the fruit as affected by reflective mulch spread 4 or 2 weeks prior to anticipated harvest. (Treatments with different letter for the same position of the fruit within the same day are statistically different (p < 0.05) (n = 60 fruit per treatment per position).
Figure 10.
Colour development dependent on fruit position within the tree of cv. Pacific Rose as measured on 14, 21 and 28 March on the red side of the fruit as affected by reflective mulch. (Treatments with different letter for the same position of the fruit within the same day are statistically different (p < 0.05) (n = 60 fruit per treatment per position).
Figure 10.
Colour development dependent on fruit position within the tree of cv. Pacific Rose as measured on 14, 21 and 28 March on the red side of the fruit as affected by reflective mulch. (Treatments with different letter for the same position of the fruit within the same day are statistically different (p < 0.05) (n = 60 fruit per treatment per position).
Figure 11.
Colour of the down facing side of the cv. Fuji fruit at first pick as affected by the timing of reflective mulch. (Treatments with different letter for the same position of the fruit within the same pick are statistically different (p < 0.05) (n = 60 fruit per treatment per position).
Figure 11.
Colour of the down facing side of the cv. Fuji fruit at first pick as affected by the timing of reflective mulch. (Treatments with different letter for the same position of the fruit within the same pick are statistically different (p < 0.05) (n = 60 fruit per treatment per position).
Figure 12.
Colour of the down facing side of the cv. Pacific Rose fruit at first pick as affected by the timing of reflective mulch. (Treatments with different letter for the same position of the fruit within the same pick are statistically different (p < 0.05) (n = 60 fruit per treatment per position).
Figure 12.
Colour of the down facing side of the cv. Pacific Rose fruit at first pick as affected by the timing of reflective mulch. (Treatments with different letter for the same position of the fruit within the same pick are statistically different (p < 0.05) (n = 60 fruit per treatment per position).
Figure 13.
Effect of reflective mulch on fruit colouration of cv. Pacific Rose at harvest- most conspicuous on the (down-facing) apex side of the apple fruit.
Figure 13.
Effect of reflective mulch on fruit colouration of cv. Pacific Rose at harvest- most conspicuous on the (down-facing) apex side of the apple fruit.
Table 1.
Percentage blush of cv. Fuji apple at each pick dependent on fruit position within the canopy.
Table 1.
Percentage blush of cv. Fuji apple at each pick dependent on fruit position within the canopy.
| Fruit Position within the Tree Canopy |
---|
Pick and Treatment | Inside | Periphery | Top |
---|
First pick | | | | | | |
Control (without Extenday) | 18.4 | b | 65.8 | b | 71.9 | b |
Extenday 2 weeks prior to harvest | 62.0 | a | 78.1 | a | 74.1 | b |
Extenday 4 weeks prior to harvest | 68.6 | a | 79.7 | a | 84.4 | a |
Second pick | | | | | | |
Control (without Extenday) | 43.9 | b | 66.4 | b | 82.5 | a |
Extenday 2 weeks prior to harvest | 77.5 | a | 77.0 | a | 72.2 | a |
Extenday 4 weeks prior to harvest | 78.0 | a | 77.3 | a | 79.7 | a |
Last pick | | | | | | |
Control (without Extenday) | 37.2 | b | 63.1 | b | 73.4 | a |
Extenday 2 weeks prior to harvest | 80.5 | a | 74.4 | a | 76.9 | a |
Extenday 4 weeks prior to harvest | 75.8 | a | 77.2 | a | 76.9 | a |
Table 2.
Percentage blush of cv. Pacific Rose apple at each pick dependent on fruit position within the canopy.
Table 2.
Percentage blush of cv. Pacific Rose apple at each pick dependent on fruit position within the canopy.
| Fruit Position within the Tree Canopy |
---|
Pick and Treatment | Inside | Periphery | Top |
---|
First pick | | | | | | |
Control (without Extenday) | 39.4 | b | 74.8 | b | 90.0 | a |
Extenday 2 weeks prior to harvest | 86.3 | a | 89.4 | a | 95.3 | a |
Extenday 4 weeks prior to harvest | 92.3 | a | 91.1 | a | 90.3 | a |
Last pick | | | | | | |
Control (without Extenday) | 67.0 | b | 74.7 | b | 80.0 | a |
Extenday 2 weeks prior to harvest | 84.1 | a | 79.1 | ab | 86.2 | a |
Extenday 4 weeks prior to harvest | 89.5 | a | 89.7 | a | 88.3 | a |
Table 3.
Quality parameter (Streif index) and ripening of cv. Fuji apple at each pick dependent on fruit position within the tree canopy.
Table 3.
Quality parameter (Streif index) and ripening of cv. Fuji apple at each pick dependent on fruit position within the tree canopy.
| Fruit Position Within the Tree Canopy |
---|
Pick and Treatment | Inside | Periphery | Top |
---|
First pick | | | | | | |
Control (without Extenday) | 0.19 | a | 0.15 | b | 0.21 | a |
Extenday 2 weeks prior to harvest | 0.21 | a | 0.19 | a | 0.25 | a |
Extenday 4 weeks prior to harvest | 0.20 | a | 0.19 | a | 0.24 | a |
Second pick | | | | | | |
Control (without Extenday) | 0.13 | b | 0.12 | a | 0.14 | a |
Extenday 2 weeks prior to harvest | 0.16 | a | 0.13 | a | 0.17 | a |
Extenday 4 weeks prior to harvest | 0.16 | a | 0.14 | a | 0.13 | a |
Last pick | | | | | | |
Control (without Extenday) | 0.11 | a | 0.10 | a | 0.11 | a |
Extenday 2 weeks prior to harvest | 0.11 | a | 0.10 | a | 0.12 | a |
Extenday 4 weeks prior to harvest | 0.11 | a | 0.10 | a | 0.10 | a |
Table 4.
Quality parameter (Streif index) of cv. Pacific Rose apple at each pick dependent on fruit position within the tree canopy.
Table 4.
Quality parameter (Streif index) of cv. Pacific Rose apple at each pick dependent on fruit position within the tree canopy.
| Fruit Position Within the Tree Canopy |
---|
Pick and Treatment | Inside | Periphery | Top |
---|
First pick | | | | | | |
Control (without Extenday) | 0.44 | a | 0.19 | a | 0.40 | a |
Extenday 2 weeks prior to harvest | 0.37 | a | 0.26 | a | 0.28 | a |
Extenday 4 weeks prior to harvest | 0.38 | a | 0.29 | a | 0.32 | a |
Last pick | | | | | | |
Control (without Extenday) | 0.39 | a | 0.26 | a | 0.20 | a |
Extenday 2 weeks prior to harvest | 0.33 | a | 0.25 | a | 0.19 | a |
Extenday 4 weeks prior to harvest | 0.35 | a | 0.21 | a | 0.24 | a |
Table 5.
Influence of latitude and tree size on minimum exposure time of reflective mulches.
Table 5.
Influence of latitude and tree size on minimum exposure time of reflective mulches.
Location | Latitude | Tree Height | Weeks | Yield | Time |
---|
Southern hemisphere | | | | | |
Nelson, Southland, New Zealand | 39–41° S | 3.5 m | 2+ | 90–120 t/ha | March–April |
Northern hemisphere–North America-USA | | | | | |
Washington State, Pacific Northwest, USA | 46–47° N | 3.5 m | 3–4 | 60–90 t/ha | September |
Geneva, New York, East Coast, USA | 46° N | 3.5 m | 3–4 | 60–90 t/ha | September |
Northern hemisphere -Europe | | | | | |
South Tyrol, Italy | 45–46.5° N | 3.5m | 2+ | 60–90t/ha | Aug.–Sept. |
Lake Constance, Germany | 47.4° N | 3.5 m | 3+ | 60–80 t/ha | Aug.–Sept. |
Bonn/Belgium/Holland/Poland/ Somerset, East Malling, Kent, UK | 50–51° N | 2.8 m | 4+ | 40–60 t/ha | September |