Causes of and Solutions for Uneven Berry Size in Kyoho Grapes

Many grape growers often encounter the phenomenon of uneven berry size during production, especially with Kyoho grapes, which seriously affects yield and quality and brings considerable economic losses to growers. So what causes uneven berry size in Kyoho grapes? And how should it be solved? Let's take a look.

I. Causes of Uneven Berry Size

There are many reasons why Kyoho grapes develop uneven berry size. The root cause is poor pollination during the flowering period: the large berries are fertilized and contain seeds, while the small berries are unfertilized and contain no seeds. There are many reasons for poor fertilization. First, varietal reasons: some varieties are highly prone to uneven berry size, such as Kyoho and Jingya. Second, excessively vigorous tree growth: if Kyoho grapes grow too vigorously, with new shoots that are too thick and too long, the uneven berry size phenomenon will be more serious. Third, climatic reasons: if the grape flowering period coincides with rainy weather, it will lead to poor fertilization, resulting in uneven berry size. Fourth, improper human management: spraying pesticides during the grape flowering period can also cause poor fertilization and lead to uneven berry size. Fifth, weak tree vigor: insufficient nutrition during the young fruit swelling stage prevents the fruit from swelling in time, resulting in uneven berry size.

II. Solutions

1. Control tree vigor

When new shoots grow too vigorously, fertilizer and water should be controlled, with particular attention to the application rate of nitrogen fertilizer. For excessively vigorous new shoots, pinching can be carried out to cultivate secondary shoots into fruiting branch groups. If the tree vigor is weak, fertilizer and water management should be strengthened to promote strong tree vigor, while measures such as pinching and cluster thinning should be adopted to control the number of fruits and reduce the nutritional burden on the plant.

2. Spray pesticides reasonably

Spraying pesticides is strictly prohibited during the grape flowering period. The spraying time can be changed to before or after flowering, when spraying will not affect grape pollination. Fertilizer can also be applied during the flowering period or boron fertilizer can be sprayed, which can significantly improve the fertilization rate and fruit-setting rate, with good results. Spraying zinc sulfate solution can also prevent the uneven berry size phenomenon.

3. Fertilize reasonably

When fertilizing, the balance of nitrogen, phosphorus and potassium fertilizers should be controlled, and it is not advisable to apply any one excessively. Generally, a base fertilizer is applied once before spring budding, mainly organic fertilizer, reasonably combined with diammonium phosphate and potassium sulfate. During the young fruit stage, the ratio of nitrogen, phosphorus and potassium in topdressing should be controlled at 2:1:1, and during the color-change stage the ratio of nitrogen, phosphorus and potassium should be controlled at 1:2:2.

4. Use growth regulators

Half a month after flower drop, when the young fruits have grown to the size of beans, 20mg/kg forchlorfenuron can be sprayed to dip the clusters or spray the clusters. This can eliminate uneven berry size in grapes with obvious effect. Gibberellin can also be used to treat the fruit clusters during the flowering period or after flowering, which can also achieve the effect of eliminating uneven berry size.

The above is an introduction to the causes of and solutions for uneven berry size in Kyoho grapes. We hope it can help you. To learn more related knowledge, please stay tuned to us.