What is the reason for grape cracks

There are many kinds of fruits, including grapes. Everyone must have eaten grapes. They are small and round, and taste sour and sweet. They have a wide range of uses. In addition to being eaten raw, they can also be made into wine, raisins, etc. Grapes often have the problem of cracking, but many people don’t know what causes it. So what is the reason for grape cracking?

Table grapes are an important tree species in fruit tree cultivation in my country. Fruit cracking often occurs before harvest, especially in rainy years in the late stage of fruit ripening. Fruit cracking not only affects the appearance of the fruit, but also leads to infection by exogenous microorganisms and rot, which seriously reduces the commercial value of the fruit. It is a physiological disease that cannot be ignored in production.

1. Types and manifestations of fruit cracking

Grapes often crack during the ripening period, causing heavy losses. The location and type of fruit cracking vary depending on the variety. Generally, there are two types of fruit cracking: dense-grain type and sparse-grain type. The causes and mechanisms of their occurrence are as follows: 1. Dense-grain type fruit cracking: The reason is that the early grains are closely connected, resulting in cork cracking. As the fruit develops, the peel and roots absorb a large amount of water, generating intra-grain turgor pressure, and the fruit cracks in the cracked part where the grains are in contact.

2. The same principle applies to cracked fruits with sparse grains, except that the cracking site is not at the contact point between the fruit and the grains, but at the top of the fruit or near the fruit stalk where the skin is weaker. Absorbing a large amount of water will promote cracking. Sometimes there are many fruits and many cracked fruits. Sparse-grain type fruit cracking: There are three situations: ⑴ The top of the fruit cracks, which occurs at the root mark. The juice rarely overflows and basically does not infect good fruits. The harm is relatively small, but it occurs more commonly.

⑵ Cracks at the pedicel, that is, cracks from the base of the stalk to the equator. The cracks are large and the juice overflows, which has a great impact on the quality of the fruit. Once it occurs, the losses are serious.

⑶ Cracks in the cork area occur on the surface of the fruit where cork is formed. Very little juice flows out, it is not contagious, and the harm is relatively small, but it seriously damages the quality of the fruit.

2. Causes of fruit cracking: 1. It is mainly due to the fragility of the grape skin tissue, especially the weakening of the skin strength as the fruit matures.

2. It is related to the increase of turgor pressure inside the fruit caused by cultivation conditions and climate changes. Among them, soil has the greatest impact on fruit cracking. Compacted soil and poor drainage are easy to cause cracking.

More fruit.

3. The amount of fruit produced is also related to fruit cracking. If there are too many fruits, fruit cracking is likely to occur.

4. When there is a lot of rain in the rainy season and the temperature changes greatly during the coloring period, fruit cracking is likely to occur. Fruit cracking is particularly common in trees with poor coloring and in years with poor coloring.

5. Fruit cracking at the cork position is mainly caused by the small space around the fruit cluster. Under the action of wind, the fruit grains rub against the branches and leaves to form cork. The local tissue becomes fragile and cracks occur at the cork position as the fruit expands.

6. Fruit cracking is also closely related to seedlessness. The cone scar of seedless fruits is large, and this part is full of mold during rainy seasons, which damages the peel and causes it to crack. This is one of the reasons for fruit cracking. Another reason is that fruit cracking occurs in fruits with only a single seed. The single seed is biased to one side, and the side with the seed is well-developed, while the side without the seed is poorly developed, and it is easy to crack with a slight impact.

7. The main reason for Kyoho grape fruit cracking is the change in soil moisture. The fruit expands slowly in the second growth stage and rapidly in the third growth stage. The fruit surface is deformed, forming cracks and depressions and other weak tissues. Water is absorbed from the roots and fruit surface to generate turgor pressure, causing the cracks and depressions to split open.