Cluster Berry Research Articles

Sampling for Degrees Brix in Vineyard Plots

Degrees Brix of berry samples and cluster populations were studied from 1977 to 1980 in a mature block of Thompson Seedless grapevines at Davis, California, as well as the °Brix of outer berries of a number of varieties. In 1983, berry and cluster sampling were compared in a crop thinning trial in a commercial vineyard of Cabernet Sauvignon near Oakville, California. The purpose of these experiments was to determine estimates of sampling accuracy and an optimum sample size for precision. Berry samples were generally of higher °Brix than cluster samples. Variances experienced with berry and cluster samples agreed well with standard curves relating sample size to expected variance. In the Cabernet Sauvignon trial, two 10-cluster samples gave a calculated precision equal to two 50-berry samples for detecting a significant treatment difference of 1.0° Brix. Cluster sampling is recommended for greater accuracy.

ブドウ (品種巨峰) の一番果および二番果の着果と発育におよぼす摘心時期の影響

1. Topping before bloom with removal of lateral shoots produced a slightly longer clusters in the first crop compared with those not treated, and augmented the number of seeded or seedless berries per cluster, resulting in a marked increase in cluster weight. On the other hand, the crop included some clusters which did not color, and showed a decreased refractometer index of the fruit juice, when the second crop was left on the second lateral shoot. Topping after bloom with removal of the lateral shoots showed few or no effects on berry weight, seeded berry set, cluster length and cluster weight.2. Treatment of clusters in the first crop with gibberellin after bloom promoted the enlargement of both seeded and seedless berries, improving the weight and shape of the cluster. Especially, seedless berries treated with gibberellin showed a value about 2.5 times, 10.9g, that of those untreated, on control shoots. The weight of clusters treated with gibberellin on the shoots was on the average about twice as much as that of the untreated clusters, 196g. The refractometer index and acidity in both seeded and seedless berries decreased with the treatment of gibberellin.3. Topping at node-order 10 with removal of lateral shoots promoted the development of second lateral shoots arising from axillary buds on the bearing shoots, causing them to bear the second crop. In those treated before bloom toward the end of May, the lateral shoots and the berries of the second crop grew most vigorously compared with those treated at other topping times, though the bearing rate of the clusters per shoot and the activity of their development were a little low. The bearing rate of clusters, the development of rachises and their number showed the utmost value in those treated by topping after bloom in the middle of June. The same result with regard to the age of bearing shoots topped after harvest was obtained by topping at the green part. Clusters produced from this topping contained more nitrogen and carbohydrates than those from topping at the tip of the bearing shoots which were not so well differentiated and had fewer rachises. If the topping time was delayed or if the topping was performed at a mature part of the bearing shoots, the second lateral shoots became weaker in growth and bore clusters with aborted rachises.4. Berries of the second crop grew less vigorously than those of the first crop. Berry weight of the second crop produced by topping on May 31 revealed a maximum of 8.8g at harvest and that from July 13, 6.4g. The number of berries per cluster in the second crop born by topping toward the end of May through late June was about 2 or 3 times more than that of the first crop. The cluster weight was also superior to that of the first crop.5. The second crop showed a higher refractometer index and acidity than the first crop. And as the topping was late, there was also a tendency for the refractometer index to lower, but the acids to increase. However, the quality of the second crop was improved by delaying the harvest time or by covering the plants with plastic film in September, producing an increase in soluble solids and a decrease in acidity.

Control of Grape Berry Moth, 1977

Abstract Five insecticides were screened for efficacy against grape berry moth on grapes in North East, PA. Plots consisted of 6 vines in a row replicated 3 times in a randomized block design. Three vines within rows and one row between treated rows isolated the plots. Sprays were applied using an Ortho Spray-ette Queen Size garden sprayer operated off a high pressure hose on a Myers 61256ET2 hydraulic sprayer. Operating pressure was 100 psi. Sprays were applied to run-off resulting in 200 gal of solution being applied per acre. The equivalent of 4 oz DuPont spreader sticker per 100 gal was used with each treatment. Spray application date was July 1, 1977. Treatments were evaluated on Auguit 1 by counting 50 berry clusters at random per plot to determine the number infested by first generation larvae.

Effects of Gibberellic Acid on Berry Enlargement, Yield and Cluster Compactness of Thompson Seedless Grapes

SummaryThe effects were studied of different GA treatments on cluster compactness and berry size in Thompson Seedless grapes. Applications of GA (15–20 ppm) at the full-bloom stage increased average bunch and berry weights appreciably when followed by a spray of 60 ppm at the fruit-set stage. These applications did not increase cluster compactness.

Effect of N, P, K, and Ca fertilizer application on the growth and yield of grape vines planted in granitic soil and diluvial soil derived from granite

1. In the district of Seto Inland Sea, most of orchards are located on the granitic soil or on the diluvial soil originated from granite. Inthis experiment the effects of application of N, P, K, and Ca fertilizers on the growth and yield of grapes were studied by planting vines in the pots filled with either the granitic soil or the diluvial soil.2. When observed with non-fruiting vines in the first and second experimental years. the growth in both soils was most inferior at the non-fertilizer plot, followed by in the orde of at the non-P plot and at the non-N plot. On the contrary, the non-K plot and the non-Ca plot were similar or somewhat superior to the completely fertilized plot in their growth. However, in the third experimental year the growth became most inferior at the non-K plot, probably on account of fruit bearing. When the barnyard manure was added to the completely fertilized plot, the growth was more promoted.3. In a comparison of the growth beetween the both soils, the granitic soil was better than the diluvial soil in all the plots. With the progress of the experimental year, it became difficult of find out any difference of the growth among the non-K plot, the non-Ca plot, the completely fertilized plot, and the completely fertilized plot applied with the barnyard manure.4. When the effect of fertilization on the fruit bearing was observed, no flower cluster was born at the non-fertilizer plot and non-P plot of the granitic soil and at the non-P plot of the diluvial soil. Although flower clusters were born, number of berry clusters and their total weight were least, and their maturity was markedly delayed at the non-N plot of both soils. This trend was more remarkable in the granitic soils. Concerning the number of berry clusters and their total weight, the non-K plot, the non Ca plot and the completely fertilized plot applied with barnyard manure in both soils were all similar or somewhat superior to the completely fertilized plot. When compared throughout all the plots, both soils were almost the same in the number of berry clusters, but the granitic soil produced heavier crops in weight and the diluvial soil bore the berries of higher sugar content.

The Black Vine Weevil, Brachyrhinus sulcatus, as a Pest of Grapes in South Central Washington1

The black vine weevil ( Brachyrhinus sulcatus (F.)) caused injury during 1961 to Concord grapes in south central Washington by feeding on berry pedicels and cluster stems. Injury resulted in reduced berry weight and loss of berries or portions of the cluster. Weekly counts on 20 tagged clusters per cover crop provided estimates of loss (tons per acre) for grapes grown in 5 different cover crops, as follows: no cover, 3.36; oats and vetch, 3.45; alfalfa, 2.42; creeping red fescue, 3.08; and creeping red fescue in combination with oats and vetch, 3.29. Weevils caught in specially designed funnel traps indicated B. sulcatus was closely associated with creeping red fescue as a cover crop. Injury in other cover crops was apparently the result or adult movement away from creeping red fescue.