Figure 1
Upper and bottom surfaces of the PET raft for vegetable floating culture. The ¾-inch PVC pipe (1), elbow connector (2), T-connector (3), arranged PET bottles (4), and stainless mosquito net (5)
Table 1
Leaf character variation of the Swiss chard in different cultivation systems and between three cultivars measured 14 and 21 days after transplanting
| Petiole length (cm) | Leaf length (cm) | Leaf width (cm) | Leaf thickness (cm) | Number of leaves per plant | Midrib to petiole ratio | |
|---|---|---|---|---|---|---|
| 14 DAT | ||||||
| Conventional | 8.28 ± 0.27 a | 8.89 ± 0.37 a | 5.45 ± 0.24 a | 0.48 ± 0.03 a | 4.08 ± 0.13 a | 1.11 ± 0.06 a |
| Floating | 8.79 ± 0.41 a | 8.45 ± 0.43 ab | 5.32 ± 0.26 a | 0.53 ± 0.04 a | 3.96 ± 0.15 ab | 0.98 ± 0.05 a |
| Bottom-wet | 8.48 ± 0.33 a | 7.98 ± 0.27 b | 5.18 ± 0.26 a | 0.50 ± 0.02 a | 3.62 ± 0.11 b | 0.97 ± 0.03 a |
| P-value | 0.49 | 0.06 | 0.65 | 0.26 | 0.03 | 0.11 |
| ‘Red Ruby’ | 8.82 ± 0.31 a | 8.02 ± 0.19 b | 5.09 ± 0.26 a | 0.43 ± 0.02 c | 4.04 ± 0.15 a | 0.91 ± 0.02 b |
| ‘Yellow Canary’ | 8.26 ± 0.32 a | 9.37 ± 0.43 a | 5.13 ± 0.25 a | 0.59 ± 0.03 a | 3.87 ± 0.11 a | 1.18 ± 0.07 a |
| ‘Pink Passion’ | 8.47 ± 0.39 a | 7.93 ± 0.25 b | 5.46 ± 0.24 a | 0.49 ± 0.02 b | 3.81 ± 0.16 a | 0.97 ± 0.06 b |
| P-value | 0.40 | <0.001 | 0.41 | <0.001 | 0.33 | 0.003 |
| 21 DAT | ||||||
| Conventional | 12.9 ± 0.50 b | 13.5 ± 0.44 ab | 8.90 ± 0.45 ab | 0.46 ± 0.02 a | 5.87 ± 0.18 a | 1.07 ± 0.06 a |
| Floating | 15.0 ± 0.56 a | 14.5 ± 0.63 a | 9.42 ± 0.25 a | 0.46 ± 0.03 a | 5.53 ± 0.10 a | 0.98 ± 0.05 ab |
| Bottom-wet | 14.1 ± 0.63 ab | 12.7 ± 0.60 b | 8.28 ± 0.45 b | 0.40 ± 0.02 b | 4.95 ± 0.20 b | 0.91 ± 0.03 b |
| P-value | 0.04 | 0.015 | 0.09 | 0.02 | 0.02 | 0.05 |
| ‘Red Ruby’ | 13.1 ± 0.53 b | 12.6 ± 0.57 b | 8.42 ± 0.60 a | 0.42 ± 0.02 a | 5.59 ± 0.21 a | 0.97 ± 0.03 b |
| ‘Yellow Canary’ | 14.1 ± 0.65 ab | 15.1 ± 0.44 a | 8.99 ± 0.32 a | 0.45 ± 0.03 a | 5.11 ± 0.17 b | 1.10 ± 0.07 a |
| ‘Pink Passion’ | 14.8 ± 0.56 a | 12.9 ± 0.42 b | 9.19 ± 0.22 a | 0.46 ± 0.02 a | 5.66 ± 0.22 a | 0.90 ± 0.03 b |
| P-value | 0.09 | 0.0005 | 0.29 | 0.27 | 0.04 | 0.009 |
[i] Mean ± standard error followed by the same letters within each column were significantly different based on LSD at P ≤ 0.05 for each treatment and days of data measurement; DAT – days after transplanting
Figure 2
The effect of cultivation systems and cultivars of the Swiss chard on fresh weight (A–B) and number of leaves (C–D) at 22, 25, and 28 days after transplanting (DAT). The different letters on standard error bar are significantly different based on the LSD at p ≤ 0.05
Table 2
Differences in the fresh and dry weight of leaf blades and petioles of Swiss chard cultivated using conventional, floating, or bottom-wet culture
| Cultivation | Blade FW (g) | Blade DW (g) | Petiole FW (g) | Petiole DW (g) |
|---|---|---|---|---|
| 22 DAT | ||||
| Conventional | 27.6 ± 0.25 a | 2.91 ± 0.12 a | 12.9 ± 0.53 ab | 1.22 ± 0.05 a |
| Floating | 31.1 ± 5.30 a | 2.86 ± 0.38 a | 15.3 ± 0.63 a | 1.07 ± 0.07 a |
| Bottom-wet | 19.9 ± 4.44 b | 1.70 ± 0.31 b | 9.9 ± 1.71 b | 0.73 ± 0.04 b |
| 25 DAT | ||||
| Conventional | 37.6 ± 2.36 ab | 3.62 ± 0.07 a | 18.6 ± 0.63 b | 1.56 ± 0.10 a |
| Floating | 49.6 ± 4.63 a | 4.73 ± 0.51 a | 31.1 ± 1.75 a | 2.15 ± 0.07 a |
| Bottom-wet | 34.2 ± 7.49 b | 3.62 ± 0.36 a | 20.0 ± 6.33 b | 1.74 ± 0.30 a |
| 28 DAT | ||||
| Conventional | 44.4 ± 0.41 b | 5.48 ± 0.18 a | 24.3 ± 2.84 b | 2.39 ± 0.19 a |
| Floating | 57.1 ± 6.56 a | 5.86 ± 0.72 a | 41.3 ± 2.16 a | 3.10 ± 0.27 a |
| Bottom-wet | 45.6 ± 7.82 b | 5.28 ± 0.62 a | 27.9 ± 3.38 b | 2.91 ± 0.37 a |
[i] Note: see Table 1
Table 3
Water content of leaf blade and petiole amongst three different cultivation systems
| Cultivation | Blade water content (%) | Petiole water content (%) |
|---|---|---|
| 22 DAT | ||
| Conventional | 89.4 ± 0.44 b | 87.4 ± 3.75 a |
| Floating | 90.5 ± 0.71 ab | 92.7 ± 0.57 a |
| Bottom-wet | 91.5 ± 0.33 a | 92.2 ± 1.08 a |
| 25 DAT | ||
| Conventional | 90.3 ± 0.39 a | 91.6 ± 0.61 a |
| Floating | 90.4 ± 0.49 a | 93.1 ± 0.12 a |
| Bottom-wet | 88.5 ± 2.02 a | 91.6 ± 1.31 a |
| 28 DAT | ||
| Conventional | 87.6 ± 0.39 b | 89.9 ± 0.45 b |
| Floating | 89.8 ± 0.16 a | 92.5 ± 0.22 a |
| Bottom-wet | 88.4 ± 1.08 b | 89.8 ± 0.54 b |
[i] Note: see Table 1
Table 4
Length, fresh weight, and dry weight of the roots as affected by cultivation system in Swiss chard
| Cultivation | Root length (cm) | Root FW (g) | Root DW (g) |
|---|---|---|---|
| 22 DAT | |||
| Conventional | 33.6 ± 1.43 a | 5.67 ± 0.06 b | 0.47 ± 0.08 ab |
| Floating | 26.8 ± 2.48 b | 9.74 ± 0.08 a | 0.65 ± 0.14 a |
| Bottom-wet | 19.6 ± 1.88 c | 4.10 ± 0.05 b | 0.37 ± 0.14 b |
| 25 DAT | |||
| Conventional | 34.4 ± 3.04 a | 5.26 ± 1.31 b | 0.56 ± 0.07 ab |
| Floating | 28.7 ± 3.33 ab | 8.58 ± 1.61 a | 0.80 ± 0.15 a |
| Bottom-wet | 22.7 ± 1.33 b | 4.87 ± 1.00 b | 0.51 ± 0.14 b |
| 28 DAT | |||
| Conventional | 26.8 ± 1.73 ab | 7.77 ± 0.52 b | 0.31 ± 0.07 b |
| Floating | 29.2 ± 3.06 a | 11.30 ± 3.04 a | 0.58 ± 0.62 a |
| Bottom-wet | 24.1 ± 1.38 b | 8.28 ± 1.90 b | 0.48 ± 0.36 ab |
[i] Note: see Table 1
Table 5
Fresh and dry weights of the leaf and petiole in three different Swiss chard cultivars
| Cultivar | Leaf FW (g) | Leaf DW (g) | Petiole FW (g) | Petiole DW (g) |
|---|---|---|---|---|
| 22 DAT | ||||
| ‘Red Ruby’ | 27.6 ± 4.60 a | 2.03 ± 0.50 a | 10.8 ± 2.90 a | 0.91 ± 2.28 a |
| ‘Yellow Canary’ | 31.1 ± 6.01 a | 2.75 ± 0.49 a | 14.8 ± 2.16 a | 1.17 ± 2.08 a |
| ‘Pink Passion’ | 19.9 ± 0.68 b | 2.70 ± 0.28 a | 12.5 ± 3.00 a | 1.05 ± 1.45 a |
| 25 DAT | ||||
| ‘Red Ruby’ | 37.6 ± 3.82 ab | 3.71 ± 0.45 a | 21.2 ± 3.66 a | 1.68 ± 0.24 a |
| ‘Yellow Canary’ | 49.6 ± 10.4 a | 4.28 ± 0.70 a | 22.2 ± 6.21 a | 1.78 ± 0.27 a |
| ‘Pink Passion’ | 34.2 ± 1.88 b | 3.98 ± 0.18 a | 28.2 ± 4.36 a | 2.00 ± 0.21 a |
| 28 DAT | ||||
| ‘Red Ruby’ | 44.8 ± 6.95 a | 5.28 ± 0.62 a | 27.8 ± 5.46 a | 2.51 ± 0.21 a |
| ‘Yellow Canary’ | 52.5 ± 8.01 a | 6.12 ± 0.51 a | 31.3 ± 7.47 a | 2.86 ± 0.47 a |
| ‘Pink Passion’ | 49.8 ± 5.11 a | 5.22 ± 0.34 a | 33.6 ± 3.14 a | 2.95 ± 0.22 a |
[i] Note: see Table 1
Table 6
The leaf area estimation model and coefficient determination (R2) for ‘Red Ruby’, ‘Yellow Canary’, and ‘Pink Passion’ cultivars of the Swiss chard plant
| Cultivar | Regression | Predictor | Model | R2 |
|---|---|---|---|---|
| ‘Red Ruby’ | Zero-Intercept Linear | Length × Width | LA = 0.695 LW | 0.981 |
| Length | LA = 5.704 L | 0.924 | ||
| Width | LA = 9.816 W | 0.940 | ||
| Power | Length × Width | LA = 0.786 LW0.972 | 0.921 | |
| Length | LA = 0.406 L1.991 | 0.856 | ||
| Width | LA = 1.973 W1.746 | 0.866 | ||
| ‘Yellow Canary’ | Zero-Intercept Linear | Length × Width | LA = 0.658 LW | 0.982 |
| Length | LA = 6.302 L | 0.931 | ||
| Width | LA = 11.887 W | 0.937 | ||
| Power | Length × Width | LA = 1.138 LW0.893 | 0.934 | |
| Length | LA = 0.791 L1.707 | 0.836 | ||
| Width | LA = 2.759 W1.631 | 0.842 | ||
| ‘Pink Passion’ | Zero-Intercept Linear | Length × Width | LA = 0.666 LW | 0.976 |
| Length | LA = 6.021 L | 0.925 | ||
| Width | LA = 10.028 W | 0.927 | ||
| Power | Length × Width | LA = 0.909 LW0.937 | 0.904 | |
| Length | LA = 0.440 L1.968 | 0.829 | ||
| Width | LA = 2.472 W1.622 | 0.817 |
[i] LA – leaf area, LW – length × width, L – length, W – width