Detailed Explanation of In Vitro Forcing Techniques for Ornamental Peach Cut Flowers

The high-temperature forcing technique for ornamental peach cut flowers is a technique that allows ornamental peach branches to bloom early in an isolated state, supplying the Spring Festival market. After two years of experimental exploration by the author, good benefits have been achieved. The key points are introduced as follows.

Facility requirements: one plastic greenhouse, equipped with ventilation equipment inside, able to keep indoor temperature and humidity consistently uniform, with no great differences from top to bottom or left to right. Clean gravel, stable in nature, must not show alkalinity after being soaked in water for one month. The particles must not be too large either. A water source from which freshly drawn clean water can be obtained in time. A clean water pre-warming tank. Spraying and humidity-retention equipment. Flower branch treatment: the flower branches should be slightly more than the length and flower number required by the contract buyer, leaving some margin, which is beneficial for handling during production. After collection, transport them immediately to the greenhouse, generally not leaving them outdoors overnight. After arriving at the greenhouse, cut the lower ends into horseshoe shapes and insert them one by one into the forcing pool. If manpower is insufficient, the flower branches can first be gathered into bundles and inserted into clean water, and later inserted as they are cut. During the whole process from picking from the tree to inserting into the forcing pool, care should be taken to avoid excessive shedding of flower buds.

Technical requirements: build a forcing pool in the greenhouse and spread gravel on top. The pool should have good water retention, but it does not need to be controlled too tightly; a slight leak is actually better. Cut the flower branches to the required length and insert them into the gravel at 2 to 4 sq cm per branch, with the depth just enough that the flower branches do not fall over. Before insertion, the gravel should first be washed clean and moistened, with a little water visible in the lower layer. After insertion, go through a one-week pre-warming period, gradually raising the indoor temperature to about 25°C during the day, with a maximum not exceeding 30°C, and about 15°C at night, with a minimum not below 10°C. Maintaining such temperatures for 15 to 20 days is enough to form flowers. During this period, at night it is enough to keep the temperature from becoming too low; after the sun comes out during the day, always be alert to the temperature rising too high and the humidity being too low, which causes flower buds and flower branches to dry up. Ventilate frequently to cool down and spray to retain humidity, so that air humidity is generally not lower than 40%; the air temperature should not differ much, so as to avoid uneven flowering. The gravel in the forcing pool should be kept moist at all times; when dry, add pre-warmed water. In order to bloom earlier and bloom uniformly, gibberellin solution can be sprayed at appropriate times in the first week to quickly break dormancy; in the middle and later stages, one or several of expansion agent, chlormequat, mepiquat chloride, and paclobutrazol can be selected and poured into the forcing pool, and when pouring, it should be able to evenly moisten the gravel. During the forcing period, micro-fertilizers such as monopotassium phosphate, potassium nitrate, and ammonium nitrate can also be added, and sugars can also be added, but after adding sugar, 8-hydroxyquinoline citrate should be used for sterilization; other fungicides can also be used, with options including procymidone 2000-fold solution, thiophanate-methyl 1000-fold solution, dimethomorph 500-fold solution, thiram 1000-fold solution, metalaxyl 1000-fold solution, and thiram 1000-fold solution. These agents have been proven by experiments to have no side effects on forcing itself.

The accumulated temperature for bud break of ornamental peach is 229.3°C, for showing red is 286°C, for flower bud formation is 306.75°C, and for flowering is 494.25°C. The accumulated temperature for first flowering of wuse peach is 516.5°C, and the full flowering stage requires 584.5°C. The accumulated temperature for first flowering of purple-leaf peach is 424.5°C, and the accumulated temperature for the full flowering stage is 584.5°C. Precautions: 1. The substrate gravel must be clean and absolutely must not become alkaline after dissolving in water, so it is best to use siliceous gravel and use calcareous gravel less. The particle size is best at bean size, and sand cannot be used. 2. The daytime temperature must not remain above 30°C for a long time, otherwise it will inevitably cause humidity to be too low, very easily causing flowers and branches to dry up, so great attention must be paid to this. At night it should also not be below 10°C. 3. The density of flower branches must not be high; a closed, stuffy atmosphere will make leaf buds grow too fast and affect flower bud growth. 4. In the first week after the flower branches enter the room, the temperature must not be raised too high or too quickly. 5. The water used must be freshly drawn clean water and must not be polluted. Distilled water also cannot be used; the latter is instead not good.