Key Technical Points of Tree Body Management in Peach Cultivation

Strengthen tree nutrition 

Branch growth and leaf area expansion provide the basis for producing nutrients for flower bud differentiation, which is beneficial to flower bud differentiation. Excessive fruiting in the current year will weaken tree vigor, leading to reduced shoot growth in that year. Conversely, if the plant grows too vigorously, it consumes too many nutrients, which instead inhibits flower bud differentiation. Therefore, tree vigor should be regulated in a timely manner to resolve the contradiction of nutrient competition among peach tree growth, fruiting, and flower bud formation, so as to facilitate smooth flower bud differentiation. During summer pruning, try to improve canopy light exposure and increase the storage of tree nutrients, so that all parts of the flower organs develop fully. At the same time, strengthen fertilizer and water management after fruit harvest. 

Strengthen pest and disease control 

After fruit harvest, strengthen pest and disease control, combined with foliar fertilization, to prevent abnormal early autumn defoliation and promote leaf photosynthetic efficiency and the accumulation of photosynthetic products, thereby overcoming poor flower bud differentiation quality and pistil degeneration caused by insufficient stored nutrients. 

Artificial supplementary pollination 

Peach is a tree species with a high self-fruit-setting rate, but abnormal weather such as low temperature, overcast rain, and frost can all adversely affect fruit setting, while artificial supplementary pollination can effectively increase the fruit-setting rate and promote fruit uniformity, regularity, and a tendency to enlarge. Pollination varieties are often selected from those with abundant flowers and overlapping flowering periods. In production, when establishing an orchard, multiple varieties are often mixed and planted or planted in a ratio of 1:4 or 1:5. 

Artificial supplementary pollination is generally carried out as follows: 

1. Collection of pollen. The collection of peach anthers uses the following simple method: 1-2 days before the initial flowering stage, place the collected flowers of the pollinating variety on a smooth painted tabletop, gently rub the flowers by hand, then sieve to obtain the anthers; alternatively, place the flowers in an iron sieve with a 0.25 cm aperture, spread clean white paper underneath the sieve, then gently rub the flowers by hand, and the anthers will fall onto the white paper. Although this method wastes some anthers, experiments show that the anther loss rate is generally below 20%, and compared with taking anthers flower by flower with tweezers, work efficiency can be increased by dozens of times. 

2. Methods for treating pollen. The methods include natural air drying, heated kang drying, and electric light drying. 

Points to note when drying anthers: First, temperature. If the temperature is too high, the germination rate is low and the amount of pollen released is small; if too low, the drying time is long. The suitable drying temperature is 20-25°C, and the temperature is required to be relatively stable. Second, time. At a maintained temperature of 20-25°C, the drying time is generally about 36 hours. Third, never expose pollen to direct sunlight. The germination rate of sun-dried pollen is only 10-20%, while that of air-dried or oven-dried pollen can reach more than 50%. 

3. Storage of pollen. Besides being used for artificial pollination in the current year, if there is surplus prepared pollen, it can be refrigerated for pollination of greenhouse fruit trees in winter or for use the following year. Generally, the pollen is placed in a brown glass bottle and sealed; it can also be sealed in a plastic bag, wrapped in black paper, then packed in a plastic bag, and stored in a refrigerator below zero degrees. When using it, a germination test is needed. Pollen stored by this method generally retains a viability of more than 70% after one year. 

4. Artificial pollination. During full bloom, the collected pollen is made into sugar-urea pollen liquid and sprayed with a sprayer. The formula for sugar-urea pollen liquid is 5 kg water + 10 g pollen + 10 g urea + 5 g borax + 100 g white sugar + a little adhesive, mixed and ready. Alternatively, spraying 10-20 mg/kg of PCPA during the flowering period and spraying 20 mg of naphthalene acetic acid after flowering can both increase the fruit-setting rate. Prepared pollen can also be mixed with talc powder or milk powder at a ratio of 1:5-10, then dotted onto flowers using a rubber tip, or placed into a gauze bag and shaken in the tree so that the pollen is scattered for pollination; when pollinating, proceed from the top of the canopy and from the outside of the canopy toward the inside. Repeating this 3-4 times during full bloom can significantly increase the fruit-setting rate. 

5. Pollination by bees. In orchards where pollinating varieties account for more than 20% and are evenly arranged, releasing mason bees or honeybees during the flowering period can significantly increase the fruit-setting rate. The pollinating wild bee Osmia excavata, through experiments, has a relatively good pollination effect, and the fruit-setting rate in peach orchards can be increased by 11%. The method is to take out bee cocoons from a 4-5°C refrigerator or fruit storage 3-5 days before peach blooming, place them into prepared nest tubes, with one bee cocoon per nest tube, with the head of the bee cocoon facing the tube opening, and seal the tube opening with relatively thin toilet paper to facilitate adult bee emergence from the nest. Then hang the nest tubes (50 or 100 tubes bundled into a bundle) on the south-facing wall of the orchard watch room, near the collection nest tubes, to facilitate recovery. Release 50-70 adult bees per mu. 

Reasonably delay flowering 

1. In early spring, cover the ground with crop straw to reduce ground radiation and delay ground warming. 

2. Whitewash tree trunks to reduce trunk absorption of solar energy.