Causes of Large and Small Berries in Grapes Affecting Yield and Control Measures

Every year in August and September is when grapes hit the market, and it is also the happiest time for fruit growers, but during the planting process some problems are bound to arise, among which large and small berries severely affect yield. To solve this, you need to understand the causes and control measures of large and small berries in grapes.

I. Basic Information About Grapes

1. Main Producing Areas of Grapes

The grape is one of the oldest tree species and is cultivated all over the world. It is also known as putao, caolongzhu, cizi cherry, bodhi seed, shan hulu and so on. Most grape production is concentrated in the Northern Hemisphere. China's main producing areas include Xiao County in Anhui; Turpan and Hotan in Xinjiang; Yantai in Shandong; Zhangjiakou, Xuanhua and Changli in Hebei; Dalian, Xiongyue and Shenyang in Liaoning; and Lumiao Township, Minquan and Yifeng in Henan.

2. Per-Mu Yield of Grapes

Generally, a well-managed high-yield vineyard can reach a per-mu yield of 3000-4000 jin, and some can even exceed 4000 jin. In the Shangqiu area, some growers have achieved a per-mu yield of around 8000 jin. Ordinary vineyards yield 2000-3000 jin, while low-yield vineyards range from 1000-2000 jin. However, to achieve high yields, variety, fertilization, pest and disease control, and management are all indispensable.

3. Grape Varieties

There are more than 8000 known common cultivated varieties in the world, including table, wine-making, drying and other processing varieties. Table varieties include Pearl of Csaba, Queen of the Vineyard, Jingzaojing, Campbell Early, Thompson Seedless, Muscat Hamburg, Kyoho and so on; wine-making varieties include Baiya, Baixiexi, Dimyat, Riesling, Irsai Oliver, Coral Bead, Cabernet Sauvignon and so on. When choosing, you should select the planting varieties according to their purpose.

II. Causes of Large and Small Berries in Grapes and Control Measures

The occurrence of large and small berries in grapes is a problem that severely affects yield and quality, and benefits are also affected. Therefore, the causes and control measures are summarized below for everyone's reference.

1. Causes Related to the Grape Variety Itself

Some varieties have inherently poor pollination, which leads to large and small berries, such as Kyoho, Victoria and Jingya. To solve this problem, one option is to change varieties, pollinate by hand, or carry out seedless treatment.

2. Zinc and Boron Deficiency in Grapes

Boron deficiency in grapes makes it difficult for the pollen tube to extend, making it hard for the ovule to be fertilized and preventing seed formation; zinc deficiency leads to insufficient auxin synthesis, slow growth, fewer fruit set, and flower caps that do not easily drop, all of which can cause large and small berries. To solve this, after harvesting you can supplement with Baobei Boron at 1500 times dilution, or spray zinc fertilizers such as zinc-calcium amino acid on the leaves.

3. Adverse Weather During the Grape Flowering Period

During the grape flowering period, continuous low temperatures and rain, or high temperatures and drought, can both cause large and small berries. The former cannot be changed in open-field cultivation, and only in greenhouse grape cultivation can the temperature inside the greenhouse be adjusted to change it; the latter can be alleviated by watering, or by adopting seedless cultivation.

In addition, improper hormone application, weak growth, excessively high yield and pests and diseases are all causes of large and small berries in grapes. Everyone should take different measures according to different situations.