Detailed Explanation of Key Techniques for Growing Kyoho Grapes in the South
Grapes are a fruit we commonly eat in daily life. The small, round grapes sit tightly packed together to form a bunch, sweet, juicy and rich in nutrients, and they are especially sought after by consumers. Kyoho grape is one variety of grape, so how should Kyoho grapes be grown in the south?
Cultivation Techniques for Kyoho Grapes in the South
1. Clearing the vineyard: Among the conditions for growing Kyoho grapes, before the vines are uncovered, thoroughly clear dead fallen leaves, weeds, grape stems and so on from the vineyard, peel off the old cracked bark on the trunk and canes, and burn or deeply bury them in a centralized manner.
2. Uncover at the right time, delay training onto the trellis: In Dalian, it is generally suitable to uncover the vines from late March to early April, when the average daily temperature reaches 10°C. After removing the soil, first let the canes remain in their cold-protection state, and after the lower buds begin to swell and sprout, then tie them onto the trellis and let the canes grow at an angle.
3. Spray a fungicidal eradicant: When the buds swell into a fuzzy ball shape, spray 5 degrees Baumé lime sulfur mixture or 200-fold sodium pentachlorophenate, ensuring thorough spraying on both the upper and lower parts of the canes and on the ground.
4. Apply fertilizer and water as appropriate: Among the conditions for growing Kyoho grapes, where conditions allow, apply sufficient organic fertilizer in autumn after harvest. In spring before flowering, if it is not excessively dry, try not to apply additional fertilizer or water, and especially do not apply nitrogen fertilizer, so as to avoid excessive early growth that is unfavorable for fruit set. After the flowers drop and the berries grow to the size of soybean grains, apply fertilizer and give one heavy watering, after which water frequently in small amounts according to drought conditions.
Training and Pruning
In northern China, grape training and pruning have traditionally been dominated by the fence-type fan shape with relatively heavy pruning, or the dragon-trunk form with short-cane pruning, which is suitable for drier areas or regions where vines are buried in soil in winter. Before the 1980s, pruning in southern regions mostly followed the northern production areas by habit; for example, the White Banana grape formerly grown in Shanghai was also mainly trained in the fence-type fan shape, with high planting density and relatively heavy pruning. When I inspected Kyoho grown in Shanghai in the winter of 1982, the trellis types were the fence-pergola or fence trellis, with fan-shaped training. The fruiting canes were left too short, mostly pruned to medium or short canes, the pruning was relatively heavy, and the bud load was on the low side, which inevitably caused excessive vegetative growth of Kyoho shoots and leaves and affected fruit set. In response to this problem, we once summarized and proposed the principle of “light pruning and long training” under fan-shaped training, extending the length of fruiting canes left at pruning, mainly using long and medium canes, with the bud load increasing accordingly. This helps control excessively vigorous shoot growth and helps stabilize the tree vigor of Kyoho.
In current Kyoho production vineyards in the south, the main trellis types include the horizontal pergola, the fence trellis (single-wall fence trellis, Y-shaped fence trellis), and the fence-pergola, among others. Among these, the Japanese Hayakawa-style X-shaped training on horizontal pergolas in Jurong, Zhenjiang, and the fan-shaped training on fence-pergolas in the Shanghai suburbs are relatively standardized. Some production areas still have problems such as non-standard tree shapes and too many main canes. Especially in new cultivation areas, there is still a lack of basic knowledge of grape pruning, and strengthening the popularization of science and technology is also an urgent task.
Humidity Management and Irrigation
For suitable indicators of humidity management, according to the water requirements of Kyoho grape growth, there are also different requirements in humidity management: from bud break to before flowering, relative humidity is generally best controlled at 70%-80%; the flowering period requires relatively dry conditions, which helps anthers open and pollen disperse, but excessive drought can easily cause the abnormal phenomenon of the corolla not splitting and falling off but drying up on the stamens, affecting fruit set. During this period, humidity inside the greenhouse should preferably be controlled between 60%-65%, which is also close to the air humidity under natural open-field cultivation at the same period (60%-69%).
Watering management. After covering the greenhouse, give one heavy watering, and give the second watering when buds begin to sprout. Before individual flowers open, give one small watering as a supplement. After that, seal the whole vineyard with film. Raise the ground temperature, prevent water vapor from rising, and reduce air humidity. Wait until 95% of the flowers in the whole vineyard have finished flowering, then remove the ground film and give the first watering after flowering, give the second after 20 days, and give one watering before the berries soften; the watering management inside the greenhouse is then basically complete.
Temperature Management
For the success or failure of protected fruit tree cultivation, temperature regulation is key. Therefore, the initial 3-5 days after covering with film are a period of full curtain coverage; after the ground has completely thawed and the grapes have gone through natural preparation and brief adaptation, begin lifting the curtains during the day to raise the temperature. Temperature raising is roughly divided into three stages of management according to different growth stages. In the early stage, from bud break to before flowering, because the daytime temperature inside the greenhouse can quickly rise to 23-25°C. A greenhouse with good lighting and good insulation can raise it to 27-28°C. Note that when it exceeds 25°C, top ventilation should be slightly opened in time to control the temperature.
If the temperature is too high in the early stage, growth and development are often uneven. While ventilating, CO2 can also be supplemented. At this time, attention should be paid to insulation at night, keeping the temperature at 7-8°C. In the middle stage, around flowering, because flowering and pollination are extremely sensitive to light requirements, daytime sunlight should be increased as much as possible to raise the temperature, while ventilating in time. The suitable temperature control range is 25-28°C. If it exceeds 30°C, top ventilation should be opened to exchange air and cool down. Do a good job of insulation at night, keeping the temperature above 14°C, so as to benefit pollination and fertilization and improve fruit set rate.
In the late stage, from berry enlargement to ripening, the natural temperature begins to rise again, the temperature difference inside and outside the greenhouse is small, and the temperature inside the greenhouse is easy to control; it can be maintained at 28-32°C during the day and 15-17°C at night. The day-night temperature difference should be controlled at above 10°C, which benefits berry coloring.
Through the above content, I believe everyone has gained a certain understanding. Although Kyoho grapes can be grown in both the south and the north, the cultivation methods are not the same. When growing Kyoho grapes in the south, special attention must be paid in the later stage to temperature and humidity management, which are importantly linked to improving Kyoho grape yield and variety quality.