How long after planting grape vines do they bloom and bear fruit? Blooming sites and key management points during the flowering period
Grape vines are usually propagated by grafting, grafting excellent varieties onto excellent rootstocks; rootstocks can be propagated by sowing, cuttings, division and tissue culture.So how long does it take from planting a grape vine to blooming and bearing fruit? Where do they bloom? What are the key technical points of flowering period management? According to the Changsha grape planting base, the grape flower pedicel is 1.5-2.5 mm long, hairless; the flower bud is obovate, 2-3 mm high, with a nearly rounded apex. Grapes generally begin to bear fruit 2-3 years after planting, and the production period can reach 20 years or longer. The root system is well developed, with absorbing roots mainly concentrated in the 20-60 cm soil layer.
Where do grapes bloom from?
1. Grape flowers come from the flower buds on new shoots. From flower bud to blooming, the new shoot must undergo two years of continuous growth to complete the process. During these two years of development, we need to carefully tend to it according to the characteristics of each stage, so as to ensure that each fruiting cane has a sufficient number of healthy inflorescences and flowers, and then grow more high-quality clusters and berries.
2. The grape panicle is dense or loose, many-flowered, opposite the leaves, with well-developed basal branches, 10-20 cm long; the peduncle is 2-4 cm long, nearly hairless or sparsely covered with cobweb-like tomentum; the pedicel is 1.5-2.5 mm long, hairless; the flower bud is obovate, 2-3 mm high, with a nearly rounded apex; the calyx is shallowly dish-shaped, with a wavy margin, hairless outside; petals 5, adhering in a cap shape and falling off; stamens 5, filaments thread-like, 0.6-1 mm long, anthers yellow, ovate, 0.4-0.8 mm long, notably short and abortive or completely degenerated in female flowers; the disc is well developed, 5-lobed; pistil 1, completely degenerated in male flowers, ovary ovate, style short, stigma enlarged.
What are the key technical points of grape flowering period management?
In the grape production cycle, from the beginning of flowering to the end of flowering, it generally lasts about 4-14 days in a normal year, mostly 7-12 days. The main factors affecting grape flowering and fruiting are temperature, humidity, drought and wind. The flowering period has relatively high temperature requirements; when the temperature reaches above 25°C, grapes bloom abundantly, and the optimum temperature is 27.5°C. When the temperature is below 15°C, grapes cannot bloom normally, and fertilization will be inhibited. The suitable relative humidity during the flowering period is 56%; if it is rainy and dry, it will affect flowering and pollination. When soil moisture is relatively high, flowering time is earlier; on the contrary, flowering is later. Wind is also an important factor affecting flowering; strong wind is unfavorable for flowering and will aggravate flower drop. During the grape flowering period, 6-11 a.m. each day is the peak flowering period, with 7-9 a.m. being the peak. 3-5 days after flowering is the first physiological fruit drop period. During the grape flowering period, flowering, flower bud differentiation, and the growth of canes and leaves all consume a large amount of nutrients. During this period, the competition between vegetative growth and reproductive growth for nutrients is very intense. If a large amount of nutrients is consumed by new shoot growth, the reproductive growth nutrients cannot be satisfied, which will cause a large number of bud drop before flowering and continued flower drop after flowering, thereby reducing the fruit set rate. If during the flowering period there is too much water in the soil and poor root aeration, affecting nutrient absorption, it will also lead to flower drop. In view of the conditions and physiological characteristics of grape flowering, the production management during the grape flowering period should focus on the following aspects:
1. Topdressing. To ease the competition between vegetative growth and reproductive growth for nutrients during the flowering period and meet the needs of flowering and fruit setting, topdressing must be carried out before and after flowering, and a 0.2%-0.3% boric acid or borax solution should be sprayed before flowering to promote pollen tube elongation and increase the fruit set rate. At the same time, cane management should be carried out well to improve ventilation and light conditions in the vineyard. During the grape flowering period, in order to save nutrient consumption, work such as tying canes, removing secondary shoots, pinching, pinching cluster tips, and removing secondary clusters should be carried out in time.
2. Carry out the thinning and arranging of flower clusters well. This is an important measure to reasonably control yield and keep fruit clusters uniform and neat, and it must be done well.
3. Carry out artificial supplementary pollination for female-flower varieties. Most grape varieties are bisexual flowers and can self-fertilize. However, female-flower varieties, due to degenerated stamens, need pollination to obtain relatively high yields. Therefore, attention must be paid to artificial supplementary pollination work.
4. For varieties that need seedless treatment, plant growth regulators should be used at the right time. For example, for Kyoho series varieties, GA3 is used for the first treatment at full bloom, and the second treatment is carried out on the fruit clusters 10-15 days later.
5. Pest and disease control. 2-4 days before grape flowering, focus on controlling gray mold, black pox, anthracnose, downy mildew, rachis browning, clearwing moth, and scarab beetles.