Causes and Countermeasures of Grape Big and Small Grain Phenomenon

Causes and Countermeasures of Grape Grain size phenomenon

1 the main reasons for the phenomenon of large and small grains in grapes

1.1 self-factors. The primary reason is that the varieties are easy to degenerate. With the growth years of Jufeng grape, the degradation of tree genes is one of the reasons for the formation of large and small grains.

1.2 Environmental impact. The phenomenon of grape size is easy to be caused by freezing of branches during dormancy, freezing of flower buds at low temperature during flowering, poor pollination caused by various reasons and so on.

1.3 pruning factor. Weixian grape giant peak is absolutely dominant, and all of them are tied vertically by hedgerows, which can easily lead to overgrowth of new shoots, dense shelf surface, poor ventilation and poor light, resulting in pollen abortion, which not only reduces the fruit setting rate, but also causes loose ear. And it is easy to cause the phenomenon of grape size.

1.4 the effect of fruit quantity. Too large load, weak tree potential, poor flower bud differentiation in the next year, young fruit nutrition can not keep up with, easy to cause grape size; low load, grape vegetative growth is too prosperous, also affect flower bud development and young fruit growth, cause grape size.

1.5 factors of soil fertilizer and water. Less organic fertilizer, too much nitrogen fertilizer, excessive plant growth is easy to cause large and small grains; lack of zinc in trees, shortening of internodes in new shoots, smaller leaves, chlorosis of leaves, and easy to occur the phenomenon of large and small grains.

1.6 other reasons. The use of fruit-setting hormone, seedless agents are also easy to cause size particles; as well as grape fan leaf virus are easy to produce size particles.

2 prevention and control measures

2.1 change the frame structure appropriately. Although Lutou Village still uses hedges, it only binds the trunk, and the new shoots are allowed to grow parallel to the ground without binding, weakening the top advantage of the new shoots, so that the growth of the new shoots tends to be moderate in order to facilitate fruit setting.

2.2 reasonable pruning. Winter branch pruning grasps the principle of "thriving, weak, leaving the golden mean". The time of re-pruning before flowering is not too early, 3 ~ 5 days before flowering, the pinching tip of double-bud fruiting branch group should be long and short, the short branch should have 6 ~ 8 leaves, the long branch (strong branch) should have 8 ~ 10 leaves, the ear length less than 10 cm should not be pinched or less pinched, and the ear length less than 10 cm should be pinched. For the fruiting branches that are too strong, twist the branches above the ear to facilitate fruit setting.

2.3 adjust the load reasonably. The yield of vineyards in full fruiting period should be controlled. Generally, the yield per mu should be 2000 ~ 2500 kg. Weak branches leave no ear, moderate branches leave single ear fruit, strong branches can leave double ear fruit, and fruit press branches.

2.4 rational fertilization and watering

2.4.1 fertilization management. In general, Jufeng grape does not apply nitrogen fertilizer before flowering, but can apply root-promoting water-soluble fertilizer, apply available nitrogen fertilizer in time after fruit setting, pay attention to balanced application of nitrogen, phosphorus and potassium fertilizer in the period of young fruit expansion, and pay attention to supplement potassium fertilizer and medium trace element fertilizer from coloring stage to mature stage. After fruit harvest, organic fertilizer must be applied as base fertilizer to increase the content of soil organic matter, improve the growth environment of grape roots, and ensure a balanced and comprehensive supply of nutrients.

2.4.2 Water supply. The soil moisture is 10 cm below the surface before flowering, and the soil can be clustered and scattered when it falls to the ground, and the low-lying or clayey soil can be watered or not irrigated before flowering. Reasonable water control before flowering is beneficial to fruit setting, watering small water about 10 days before flowering to ensure soil moisture and vineyard microclimate. If watering too late or too much watering, it is not conducive to fruit setting.

2.5 adjust the content of trace elements in soil. Zinc sulfate was sprayed on the leaves 2 ~ 3 weeks before flowering, 1 ~ 2 times continuously, with an interval of 10 ~ 15 days. Because it is difficult for plants to absorb zinc from the soil, it can also be foliar sprayed with 0.1% ~ 0.2% zinc sulfate solution. Jufeng had better trim the flower spike 3 days before flowering and cut off the accessory spike with 1 ~ 2 branches at the upper end. Boron deficiency results in irregular fruit size. 1 000 times boron fertilizer was sprayed 2 ~ 3 weeks before flowering. The grape fruit with serious potassium deficiency is small and irregular, especially in the later stage of grape growth, the application of potassium fertilizer can significantly improve the fruit quality.

2.6 using secondary branches to bear fruit. The phenomenon of large and small grains has been clearly seen when the grains of grape and soybean are large. The above branches and leaves can be cut off at 5 ~ 6 leaves to stimulate the growth of secondary branches. Although the ripening period is about one week later, the fruit setting rate is high and the ear is neat. It can effectively control the size and size of grains.

2.7 use length control regulators. When the hormone containing pirauron is used as the expanding agent, the treatment concentration is more than 200mg/kg or the treatment time is too early, it is easy to produce large and small grains. Jufeng varieties should be treated 10 ~ 15 days after anthesis. Practice has proved that the use of PBO as a control agent for fruit setting in Jufengwang trees is significantly increased, and it is helpful to control the phenomenon of grape size. Special attention should be paid to the prohibition of spraying in full bloom, because spraying during flowering will affect the pollination of grapes and is easy to form large and small grains.