Apple coloration is directly related to the commodity value of the fruit. Especially for colored varieties, fruit quality and commodity value can be increased when the fruit is well colored.
Therefore, how to improve the color of the fruit and how to add color to the apple has always been a problem that fruit farmers are extremely concerned about.
Tips to Improve Apple Coloration
1. Adjust leaf fruit ratio, promote coloring
The nutrition needed for fruit growth is mainly synthesized by leaves, so the number and quality of leaves have a great influence on fruit growth.
Leaf fruit ratio appropriate, good leaf quality, high photosynthetic efficiency, good fruit growth, high sugar content. Generally speaking, fruit with high sugar content, coloring is good. Thinning flower and fruit is an important means to adjust leaf fruit ratio and improve fruit nutrition condition.
2. Improve the orchard light conditions
In addition to photosynthesis, light can also directly affect fruit coloring, such as ultraviolet light can promote fruit coloring.
To maintain a reasonable density of branches, adjust the direction and number of branches on the back of the periphery, as soon as possible to remove light-blocking branches.
3. Increase the application of phosphorus and potassium fertilizers
The research confirmed that when the nitrogen content of apple leaves was about 2%, the apple tree leaf petiole presented red and slightly purple color, and the apple fruit color was better.
Therefore, in the late stage of apple growth, we must strictly control the amount of nitrogen fertilizer and pay attention to increasing the amount of potash and phosphorus fertilizers.
4. Maintain normal moisture
After entering July, the rain will gradually increase, and the apple trees often grow vigorously in autumn, which not only consumes a large number of photosynthetic products but also causes poor ventilation and light transmission in the canopy. It is extremely unfavorable for the accumulation of sugar in the fruit, thereby affecting the coloring of the fruit.
After July, we must strengthen and pay attention to the relative balance of soil moisture in the orchard. Irrigation should be done in time when it is dry, and drainage should be done in time when it is flooded.
5. Spray with apple colorants
ABA enables more organic acids in the fruit to be converted into sugars. Increased sugar content promoted anthocyanin formation and fruit coloration.
The reduction of organic acid content in fruit may weaken the inhibitory effect on Vc synthesis in fruit, so that the content of Vc in ABA-treated fruit increases at harvest. ABA accelerates fruit ripening while promoting fruit coloring.