Solution to Flower and Fruit Dropping in Apricot Cultivation Techniques

  In the production of fruit trees, the phenomenon of serious drop of flowers and fruits and low fruit setting rate is common in apricot trees. The trees are full of flowers and half of fruits, and even full of flowers and fruits.

Solution to Flower and Fruit Dropping in Apricot Cultivation Techniques

1. Analysis of Flowering and Fruit Dropping Phenomenon of Apricot Trees
（1） Internal causes
  Fruit plastic originated from flowering and fruiting, but flowering is not necessarily fruitful. Only after the pollen of stamen was received on the stigma of pistil in the flower organ, after fertilization, the ovary enlarged, the young fruit began to grow and develop. However, most apricot trees have the phenomenon of pistil abortion or self-filling, leading to apricot flowering and fruitless.
（2） Environmental factors
  Flowers and young fruits of apricot trees are very sensitive to low temperature. When the temperature is lower than - 2.2 C at full blooming stage and the fruit setting stage is lower than - 0.6 C, they will suffer frost damage. Flowers and young fruits are prone to fall off in early spring and late frost, which will result in blooming without fruit setting. In the case of low temperature, rainy or windy weather, pollen transmission is not conducive, affecting insect activities such as honeypot, reducing the chance of apricot pollination.
（3）Management Reasons
  The soil is barren, the nutrition is insufficient, the tree vigor premature senescence, even the formation of flower buds, mostly flowers with imperfect flower organs, most of these flowers can not be pollinated and fertilized. Apricot trees need to consume a lot of nutrients during flowering and fruiting period, and do not fertilize in time in early spring. Because of the lack of nutrient supply, a large number of flower buds and young fruits fall off. The quality of flower bud formation and fruit setting rate will also be affected by years of no pruning, too many branches, crowded, poor ventilation and light transmission conditions.
2 Solutions to the problem of apricot blossom being unreliable
 （1）. Improving pollination
  When building a garden, the main cultivars should choose the cultivars with low abortion rate and high fruit setting rate by natural pollination. When building a garden, pollinating trees should be planted in the proportion of 1:3-4, and attention should be paid to the main cultivars should be the same as pollinating trees in flowering period, fruiting and longevity.

  For established orchards, if pollinating trees fail to meet the requirements, the fruit setting rate can be improved by high grafting or inserting flower branches into water bottles at flowering stage and hanging them on the main cultivar trees.
 （2） Artificial pollination
  Conditional orchards collect buds with buds and put them together to collect pollen 2 to 3 days before pollination. When collecting, tear the bud, pick the anther with tweezers, spread a thin layer of shade drying on the smooth paper, keep the room temperature at 20 ~25 C, after 1d~2d anther cracking, release pollen, collect it, store it in a dry vase to avoid light, and use artificial pollination when apricot blossoms.
Pollination time is best between 9 and 15 o'clock every day. When pollinating, dip the pollen with a brush and point it on the stigma of the newly opened flower, pollinating each flower 2-3 times.
3. Rational Fertilization
  (1) Base fertilizer
  Base fertilizer, such as decomposed chicken manure, stable manure, compost, fish pond mud, decomposed human manure and urine, can provide organic matter and trace elements necessary for the growth and development of apricot trees for a long time. It is the basic fertilizer, and also the basis for the flowering and Fruiting of apricot trees.
When the base fertilizer is not frozen before winter, combined with orchard tillage, it is applied once in ditches or radial holes, and the depth of fertilization is generally 40 cm to 60 cm (cm). For trees with too much fruit, weak trees and poor quality of flower buds, each plant is applied with 0.3 kg to 0.5 kg (kg) phosphorus and potassium fertilizer.
  (2) topdressing
  Topdressing is to make up for the deficiency of base fertilizer, which can be divided into pre-anthesis fertilizer, post-anthesis fertilizer and flower bud differentiation fertilizer. Pre-anthesis fertilizer is usually applied 0.2kg-0.5kg urea per plant before bud germination after thawing in spring. Young and vigorous trees do not apply fertilizer. After fertilization, irrigation is timely and permeable. This topdressing can promote the uniform flowering, reduce the drop of flowers and fruits, and is conducive to the growth of new shoots and roots.
Drupe fruit trees need adequate potassium fertilizer supply during the whole fruit-bearing period, especially at the initial fruit stage and hard nucleus stage. In production, when apricots grow to the size of peanut kernels, 0.5%-1% potassium dihydrogen phosphate is sprayed on the leaves to improve fruit setting rate.

  After flowering, apricot trees consume a lot of nutrients. After flowering, young fruits expand rapidly. New shoots and leaves begin to grow vigorously. They need more nutrients. It is necessary to apply quick-acting nitrogen fertilizer in time and with a small amount of phosphorus and potassium fertilizer. In the period of fruit enlargement or hard nucleus, quick-acting nitrogen fertilizer combined with a small amount of phosphorus and potassium fertilizer should be applied to promote flower bud differentiation and lay a foundation for high yield in the next year.
Solution to Flower and Fruit Dropping in Apricot Cultivation Techniques
4. Reducing Freezing
  (1) Irrigation
  Orchards are usually irrigated twice with fertilizer at least before bud germination and freezing. In particular, irrigation before bud germination can reduce ground temperature, postpone flowering period, and avoid frozen injury to flower buds and young fruits caused by cold in spring.
  (2) Spraying brine
  Spraying 0.1-0.3% salt water once a month before flowering and before bud germination can also reduce the degree of Frozen Flower organs.
5. Moderate pruning
  Apricot is a photophilic tree species. Its leaf buds have the characteristics of strong germination, weak branching, easy formation of flower buds and long life of latent buds. Pruning depends on species, tree potential and management level.

  The general principle is to keep the physical ability of the tree branches in view and not to prune too heavily. For the main and lateral branches at all levels, if there is room for expansion, the single branch should extend outward, and the erect branches, elongated branches, crossed branches, overlapping branches, disease and insect branches should be removed; for the more erect main and lateral branches, the branch should be stretched and branched to open angle; for the long-term slow-down fruiting branches, it should generally be retracted to 2-3-year-old branches.

  For the middle and long branches on the main and lateral branches, the growth is moderate and the thickness is suitable. If there is space, the branches should be moderately truncated to keep strong and weak, to keep straight and flat, and to cultivate fruiting branches. For trees with large flower buds, a part of medium and long fruit branches should be pruned to reduce the amount of flower buds, which is conducive to good results in the current year and to improve the quality of flower buds in the coming year.