Effect of cultivar, cluster thinning, and growing season on yield and crop load of own-rooted grapevines in the Yakima Valley, WA. Note: yield (t/ha) can be calculated by dividing crop level by 0.558.
| Crop level (kg/vine) | Clusters/vine | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Treatment | 1997 | 1998 | 1999 | 2000 | 2001 | 1997 | 1998 | 1999 | 2000 | 2001 |
| Cultivar | ||||||||||
| Cabernet Sauvignon | 5.09 ba | 9.81 | 3.68 c | 3.84 | 3.54 b | 58 b | 117 b | 82 b | 75 b | 72 b |
| Riesling | 7.36 a | 9.44 | 4.95 b | 5.97 | 6.21 a | 108 a | 148 a | 98 a | 108 a | 92 a |
| Chenin blanc | ncb | 9.04 | 6.43 a | 5.08 | 5.45 a | nc | 70 c | 65 c | 56 c | 50 c |
| Thinning | ||||||||||
| Early | 5.64 b | 7.82 b | 4.15 b | 4.55 b | 5.25 a | 76 b | 91 c | 60 c | 67 b | 70 b |
| Late | 6.05 b | 8.69 b | 4.53 b | 4.79 ab | 4.11 b | 74 b | 105 b | 73 b | 75 b | 57 c |
| Control | 6.98 a | 11.78 a | 6.39 a | 5.54 a | 5.84 a | 100 a | 138 a | 112 a | 98 a | 86 a |
| Interaction | ***c | *** | ns | ns | ns | ns | ns | ns | ** | ns |
| Crop load (fruit/pruning weight) | Leaf area/fruit weight (m2/kg) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 1997 | 1998 | 1999 | 2000 | 2001 | 1997 | 1998 | 1999 | 2000 | 2001 | |
| aMeans within columns followed by different letters differ significantly at p < 0.05 by Duncan’s new multiple range test. | ||||||||||
| bnc: data not collected. | ||||||||||
| cCultivar x thinning interaction; *, **, ***, ns: significant at p < 0.05, 0.01, 0.001, or not significant, respectively. | ||||||||||
| Cultivar | ||||||||||
| Cabernet Sauvignon | 3.79 b | 7.30 b | 5.76 c | 4.02 c | 2.64 c | nc | nc | 3.77 a | 3.22 a | 2.82 a |
| Riesling | 9.77 a | 10.03 a | 11.43 b | 10.47 a | 8.20 a | nc | nc | 2.51 b | 1.67 c | 1.66 c |
| Chenin blanc | nc | 10.92 a | 15.93 a | 7.89 b | 5.77 b | nc | nc | 2.04 b | 2.33 b | 2.26 b |
| Thinning | ||||||||||
| Early | 6.74 | 7.81 b | 9.23 b | 6.60 c | 5.57 b | nc | nc | 3.45 a | 3.00 a | 2.25 ab |
| Late | 6.45 | 8.27 b | 9.14 b | 7.08 b | 4.38 c | nc | nc | 3.17 a | 2.35 b | 2.65 a |
| Control | 7.48 | 12.17 a | 14.76 a | 8.69 a | 6.66 a | nc | nc | 1.70 b | 1.88 b | 1.85 b |
| Interaction | ns | ** | *** | ns | * | ns | ns | ns | ||