(1) temperature

The optimum growth temperature of passion fruit is 15-33℃, above 33℃, below 15℃, the growth is slow, and basically stops below 10℃. There is no obvious chilling injury at low temperature around 6℃, and leaves and vine shoots appear mild chilling injury below 6℃. At 4℃, purple passion fruit can dry up. However, frost below 0℃ for a long time will cause the crown to die. However, passion fruit seedlings are not cold-tolerant, and can also be planted in autumn in cold areas with heat preservation measures.

Passion fruit has strong resistance to advection and low temperature, but weak resistance to radiation and low temperature. Frost is easy to cause injury, and the ground with heavy frost dries up and dies, but it can generally continue to germinate and grow in the coming year.

In the hot and dry season, passion fruit grows slowly, leaves turn yellow or wrinkled, stress resistance decreases, and some plants get sick in stems or stems, resulting in the death of the whole plant. In the flowering and fruiting period, when encountering high temperature and drought, the flower buds can't develop normally, then turn yellow and fall off, and some fruits will wrinkle or even shrink and fall off.

(2) Moisture

Passionflower grows best when the annual rainfall is between1500-2,000 mm and is evenly distributed. The annual rainfall in commercial development and planting areas should not be less than 1000 mm, and the number of water shortage will be reduced and the node length will be shortened, thus reducing the extension length of the whole vine, the number of flowers and the yield. Stems become thinner, tendrils become shorter, leaves and flowers become smaller, lateral roots become less, leaves fade, new leaf axils die, and the edges and tops of leaves appear necrosis. Water shortage leads to the decrease of P, Ca, Mn, Fe, Zm and B contents, which affects the nutrient absorption and metabolism of passion fruit, thus affecting the normal growth and development of plants.

Too much water (such as soaking) and high humidity can easily cause diseases, such as stem rot. After the roots of passion fruit seedlings were soaked in water for 4-6 days, the root respiration was affected by lack of oxygen, which controlled the growth of aboveground parts, resulting in the growth of petioles, the aging and shedding of leaves, the expansion and cracking of stem bases, the appearance of punctate white soft tissues and the growth of adventitious roots. Soaking in high temperature in summer is particularly harmful, and soaking in winter is slightly harmful. Therefore, passion fruit should be planted in a place with good drainage and irrigation.

(3) Lighting

As a tropical fruit, passion fruit likes plenty of sunshine to promote the growth and nutrient accumulation of branches and vines. If the light is insufficient, the growth is slow, there are too many branches and too many pests and diseases. But if the leaves are exposed to the hot sun and baked at high temperature, the leaves will turn yellow, the edges of the leaves will become upturned, the branches will grow slowly, and even the fruits will shrink and fall off.

Passion fruit is a long-term plant with photoperiod effect, that is, long sunshine hours (more than 12 hours) can promote flower bud formation and flowering. Passionflower grows well, is rich in nutrition and grows fast in areas with annual sunshine time of 2300-2800 hours. Generally, water and fertilizer cultivation management should be done well after sowing in early spring, and flowers and fruits can continue in that summer.

(4) Soil

Passion fruit has strong adaptability and low requirements for soil. It can be planted in sandy loam, red loam, kaolin and other flat land or sloping land with good irrigation and drainage, and must not be planted in places with long-term low-lying and stagnant water. Large-scale production, it is best to plant in fertile, loose and well-drained places, and paddy fields with irrigation and drainage are the best.

The optimum soil pH value of passion fruit is 5.5-6.5; When pH < 5.5, the acidity is too high, which is easy to cause stem rot. It is necessary to neutralize some acidity with lime before the high temperature and rainy season in summer, which can improve the soil.

(5) The influence of climatic factors on the growth and development of passion fruit.

The growth and development of passion fruit have obvious seasonal changes. In spring and autumn, nutrition grows rapidly and there are many flowers and fruits. There are few high-temperature fruits in midsummer and few flowers and fruits in winter. In the flowering and fruiting period, the fruit setting rate in sunny days is higher than that in rainy days. Passion fruit generally takes 60-80 days from flowering to fruit ripening, and the time required in spring is shorter than that in autumn.

Practical high-yield cultivation techniques of passion fruit

First, how to establish an orchard?

1. Land selection and reclamation

(1) land selection

Passion fruit has strong adaptability, rough growth and fast growth; It grows well in tropical and subtropical regions and can blossom and bear fruit in temperate regions; The requirements for soil are not high, and it can be planted in sandy loam, red loam, kaolin and other soils. Slope land, mountain land, flat land and paddy field that can be irrigated and drained can be used, and low-lying and waterlogged land cannot be chosen to build gardens.

(2) Reclamation

When building the garden, it is necessary to plan planting areas, roads, packaging yards, tool houses, windbreaks and flood control systems. Remove weeds, trees or other debris and stones that hinder farming in the planting area; Then level the land, and you can cultivate it completely or make holes. For mountain planting and orchard reclamation, the planting bandwidth should be greater than 1. 1 m, and the slope should be 5-8. A small ridge with a height of 20 cm and a width of 30 cm should be built at the outer edge of the planting belt.

Build a shelf

Passion fruit is a vine, which can grow and develop normally with the support of scaffolding. Therefore, it is necessary to build corresponding scaffolding. After investigation, it was found that fruits were hung on framed plants at the same planting time, but no fruits were found on plants without frames. Scaffolding is convenient for management and harvesting, and also creates a good photosynthetic space and ventilation environment, reducing pests and diseases. There are flat-top, fence, herringbone, arch and portal, vertical, T-shaped, double T-shaped and so on. Scaffolding materials are cement columns or stone pillars, and the investment is large. In order to reduce the cost, you can use peeled, dried and preserved wooden strips as columns. Natural trees (living columns) can be used instead of those planted in mountainous areas, and the effect is very good.

Passion fruit is planted on the horizontal frame (flat top), which is convenient for picking fruit. There is no grass under the tree and it is suitable for sightseeing. However, the erection cost is high and it is difficult to trim in the coming year.

Hedgehog frame, the row spacing is 2m, the plant spacing is 3m, every 667m2 species 1 10, the height of the column is generally 1.8-2m, 80cm, 130cm, and a wire is pulled at the highest position. The frame has good lighting and ventilation, and is easy to trim. In addition, the fruit will not stay at the top of the shed, it can automatically fall down for harvesting. This hedge frame can automatically inhibit overgrowth, hang fruits into strings, and the yield is higher than other trellis frames 15%-20%.

Step 3: Planting

Passion fruit can be planted all year round. Fence frame planting, plant spacing 3 meters, row spacing 2 meters, every 667 square meters 1 10 plants. Digging a planting hole with the specification of 60 cm× 60 cm× 60 cm; When digging a pit, the topsoil and subsoil should be stacked separately; Apply 25 kg of decomposed manure or garbage manure to each hole, add 0.2 kg of calcium superphosphate or 0.2 kg of compound fertilizer as base fertilizer, mix the topsoil and fertilizer evenly, make the hole soil 20 cm higher than the surface, and then cover it with a layer of core soil. Choose cloudy days or sunny days after rain from February to May, when the temperature and humidity are appropriate and the survival rate is high; When planting, it is best to classify seedlings according to their height, size and root quality, and separate strong seedlings from weak seedlings for future field management. Then turn up the soil in the planting hole and mash it. For each plant in each hole, first dig a small hole 20 cm deep and slightly compact the subsoil. When planting seedlings, tie the roots well, thoroughly water the roots, then fill in loose soil and gently compact them. Keep it moist until the seedlings survive. If it is planted in summer and the sun is strong, pay attention to shading and moisturizing.

Second, the daily management of the orchard

1. Fertilization

Generally, if you put enough fertilizer before planting, you can't fertilize again that year. If not, nitrogen fertilizer was mainly used to promote plant growth in the early stage. Rooting begins on 10- 15 days after planting, and dilute urea or dilute human manure can be applied for the first time, and then 5 kg of decomposed human manure or 0.05-0. 1 kg of compound fertilizer can be applied to each plant every 45 days. Passionflower needs more nitrogen and potassium, but less phosphorus, calcium and magnesium. Taiwan Province Province suggested that the annual fertilizer application rate per plant should be N250-300, P2O3 100- 150g, K2O600-800, and emphasized that it was unnecessary to apply too much nitrogen fertilizer after the initial growth stage, otherwise it would lead to falling flowers and reducing production. The reasonable fertilization method in Kaiping area is liquid fertilizer or furrow application. The application of liquid fertilizer is to dissolve the fertilizer first, then dilute it into liquid fertilizer and pour it around the root system to induce the root system to grow. Fertilization by furrow irrigation in Kaiping is beneficial to root expansion. Therefore, the newly planted plants should open a parallel ditch with a width of 15-20 cm and a length of 50 cm on each side. When it rains, granular fertilizer should be applied and covered with soil.

2. Irrigation

Passion fruit is a shallow-rooted plant, which likes to be moist, but it is not conducive to water accumulation and drought. Passion fruit grows fast and its branches and leaves grow big. Besides adequate fertilizer, a lot of water is needed. The key period of water demand is the germination of new shoots, flower bud differentiation and rapid fruit expansion (pre-middle stage of fruit development). However, a dry environment is needed before the physiological differentiation of flower buds and at the later stage of fruit growth, which is beneficial to the improvement of fruit quality.

Water shortage in soil will limit the vegetative growth and yield of passion fruit. If the soil is too dry (water potential =- 150 Pa), it will affect the development of vines and fruits; In severe cases, branches wither, fruits are undeveloped, and fruit drop often occurs. If the soil is short of water in spring or early summer, it will also affect the flower bud differentiation and directly cause the summer yield to decline. In order to obtain the highest yield, it is best to irrigate when the water content is low in flowering and fruiting period, so as to ensure sufficient soil water and increase yield.

When excessive irrigation or rain causes flooding, it is also not conducive to the growth of passion fruit. Long-term flooding will completely destroy the original root system, and it is necessary to grow adventitious roots from the stem and root parts or above the water surface to replace the original root system. So long-term immersion in water is very harmful to passion fruit plants.

3. Soil management

(1) intercropping

After planting 1 month, the tender root system of passion fruit can be found 25 cm away from the emergence of seedlings, and it should not be too close to the emergence of seedlings during intercropping, otherwise it will hinder the root system expansion of passion fruit; Intercropping crops can only be a vegetable, but can't grow cucurbitaceae crops such as watermelon to prevent these crops from carrying viruses; It is not suitable to interplant after production, so as not to affect the normal management of orchard and pest control. In order to facilitate fruit picking, it is not suitable to plant covered crops.

(2) intertillage

Loose and breathable soil is beneficial to cultivate the strong root system of passion fruit; Promote the robust growth of plants and obtain higher yield. In summer and autumn, when passion fruit grows, the orchard will be hoed shallowly after rain, with a depth of 5- 10 cm. The frequency of intertillage combined with weeding depends on the growth of weeds. Generally, it takes 2-3 times to grow and droop the fruit quickly. Intertillage can make the soil loose and breathable, cut off soil capillaries, facilitate soil microbial activities and decomposition of soil nutrients, reduce water evaporation and improve soil water-holding capacity.

(3) Qingyuan

After clearing the garden in winter, the whole garden should be turned over before winter. The dug soil is buried in the garden with weeds and fallen leaves. At this time, intertillage can not only improve the soil, but also plough the overwintering pests in the soil, reducing the base of pests and diseases in the coming year after exposure to the hot sun, drying and low temperature in winter.

4. Tree management

Passion fruit is easy to be damaged, and careless field operation or heavy wind and rain will hurt plants. In particular, the injury of the main vine provides an opportunity for pests and diseases. When working in the field, the diseased plants should be removed in time, the mild plants should be prevented in time, the severe plants should be pulled out and burned in time, and the diseased points and surrounding soil should be disinfected. In addition to careful field operation, herbicides can also be used to kill weeds in the field, which is efficient, non-toxic, low cost, and can reduce mechanical damage and reduce morbidity. However, herbicides such as glyphosate should not be used, and special attention should be paid not to spray on the branches and leaves of passion fruit. In areas with frequent typhoons or strong winds, fences should generally not be higher than1.6m.. It is best to set up a windproof system to minimize the damage caused by strong winds. Winter is vulnerable to frost and cold, so it is necessary to set up a cold protection system as much as possible and pay attention to protecting the main vines and other aboveground parts.

5, plastic pruning

(1). Guide the main vine to stand.

After the seedlings resume growth, the lateral buds below 60 cm should be erased in time to make the main vines grow fast and thick. At this time, it is necessary to insert columns and guide the main vines to the shelves. When the main vine reaches the top, it can be cored, which can make the side vine grow fast and thick. It is necessary to guide the lateral vine to grow spirally on the wire frame frequently. When the lateral vine is full, break the top of another plant and tie it 30 cm beyond it. The lateral vines move to one side, which is beneficial to the full shelf of fruit branches as soon as possible. If the lateral vines are damaged by pests and diseases, they should be replaced with strong first-class fruit branches in time.

(2) Pruning

The autumn shoots germinated after fruit picking in the previous year sprouted fruiting vines at almost all nodes above the middle. Leave as many fruiting branches as possible in the previous year, but in order to prevent the leaves from being too dense, prune as much as possible after picking the fruits, and finish pruning at the latest in the beginning of 10/0, otherwise the new shoots will become shorter and shorter after 10, and pruning in February of 165438 will promote the fruits. If the overgrown branches and branches with diseases and pests are pruned at the end of March, more multi-level branches may sprout, thus increasing the number of buds and fruits, which is conducive to increasing the yield. Therefore, whether to prune in spring depends on local cultivated varieties, management level and climatic conditions.

Prune with the main vine as the center, and leave about 50 cm (crown width about 1 m) for pruning. All tendrils entangled in the shed should be removed. Many autumn shoots germinate immediately after heavy pruning and can become the fruiting mother branches of the next year. As a result, the mother branches germinate more, which can ensure the number of flowers, so it must grow to at least 20 knots a year to be rich.

The pruning method of the fence frame is as follows: after the main vine of the annual plant reaches the iron wire of the trellis, two main branches are left and extend along the horizontal iron wire, and fruiting branches grow on the main branches, so that the fruiting branches droop and grow; As a result, the branches were covered with fence-like scaffolding space, and the branches close to the trunk were full of fruits first; Prune the fruits of these branches to 2-3 knots immediately after they mature and fall; Buds sprouting from the base of main branches can form new fruiting branches; After harvesting the last batch of fruits in winter, cut all the fruiting branches from the base, leaving 1-2 leaves.

6. Artificial insemination

(1). Stigma structure and fertilization process of passion fruit.

The stigma of passion flower is dry. Pollen falls on the stigma, and it can germinate and grow into pollen tube after half an hour, and smoothly passes through the intercellular space between villous tissue centers. After 1 hour, the pollen tube enters the guiding tissue. After 18 hours, the fertilization rate of ovules in ovary can reach 80%, and the development speed of ovary is amazing. Generally, the size of the fruit has been set in about 10 days.

(2) The necessity and process of artificial pollination.

The purplish red passion fruit we cultivate is a self-pollinating variety, and natural pollination is carried out by external forces such as bees, other insects or wind. The fruit setting rate of natural pollination is about 67.8%, which fully meets the production needs. Artificial pollination can greatly improve the yield and fruit quality. Passionflower blooms on time, almost every day 10: 30, and almost thousands of flowers bloom at the same time in a few minutes. Generally, the artificial pollination time is from half an hour to 5 o'clock at flowering stage. Because passion fruit is a self-compatible variety, just put a little pollen on the stigma of passion fruit flower. Generally, you can dip pollen with a brush and point it on the stigma of passion fruit flowers. Usually a person can complete about 8000 auxiliary pollination in half a day. China Organic Agriculture Network