Conditions of Flower Bud differentiation in Litchi

Litchi fruiting mother branch is strong, the mature period is suitable, the tree potential is moderate, it is easy to control winter shoots, accumulate nutrients, and is conducive to flower bud differentiation. The more organic nutrients accumulated, the better flower bud differentiation. If the tree is too prosperous, the vegetative growth is strong, which is not conducive to flower bud differentiation, it is easy to pull out flowers and leaves, resulting in reduced yield or loss of harvest; or excessively long flower spikes, consuming too much nutrition, less female flowers and more male flowers, resulting in reduced yield. If the fruiting mother branch matures too late, the accumulation of organic nutrients and carbohydrates is less and the concentration is low, which is disadvantageous to flower bud differentiation; if the fruiting mother branch matures too early, the time of controlling winter shoots is too long, although accumulating nutrients is beneficial to flower bud differentiation, it is also easy to draw winter shoots, consume nutrients and destroy flower bud differentiation. If the growth of fruiting mother branch is too weak, the vegetative growth is poor, and the accumulation of nutrients is insufficient, it is also not conducive to flower bud differentiation. The basic speculative condition of flower bud differentiation is that vegetative growth is slow or stopped. From vegetative growth to reproductive growth, the nutritional status and the type and proportion of endogenous hormones in the tree should be significantly changed to meet the needs of reproductive growth. The process of flower bud differentiation requires a large number of cytokinins to promote flower bud differentiation. The winter temperature is low, the cold time is long, the vegetative growth is inhibited, the reproductive growth is promoted and the quality of flower bud differentiation is good. Different varieties have different requirements for low temperature, such as March Red and Feizixiao, no matter whether the temperature is high or low, flower bud differentiation can be carried out. In the period of flower bud differentiation, the longer the time of low temperature, the better the flower bud differentiation. White wax and black leaves require a low temperature of 8-15. C, Feizixiao and Bai Tangzhu require 20. Below C. The last autumn shoot of litchi should be drawn from the first ten days of September to the middle of October, early-maturing varieties and late-maturing varieties. If the tree is too weak, it is necessary to apply appropriate amount of fertilizer and spray compound nucleotides for 2-3 times to improve photosynthesis and cultivate strong fruiting mother branches; if the tree is too strong, there is no need for further fertilization. At the same time, acaricides should be sprayed twice to protect the fruiting mother branch. For example, acaricide benzoate 2000 times or fruit full red 2000 times, mixed insecticide Kaifeng 2000 times or Shongwang 2000 times, or Saibokai 2000 times. When the fruiting mother branch was mature, compound cytokinin was sprayed 1-2 times to increase the cytokinin content of fruiting mother branch and promote flower bud differentiation.