Why do dragon fruit flowers turn yellow just a few days after blooming?
I think everyone is very familiar with dragon fruit. The dragon fruit we usually see most often are white-fleshed dragon fruit and red-fleshed dragon fruit. Dragon fruit is very nutritious, and is especially the best fruit for reducing internal heat. How exactly does such a delicious dragon fruit grow? Let's take a look together below!
Why do dragon fruit flowers turn yellow just a few days after blooming
If dragon fruit flowers turn yellow and drop off two to three days after blooming, this indicates that the flowers were not properly fertilized and therefore have no vitality. On the one hand, because red-fleshed dragon fruit exhibits self-incompatibility, it is best to plant red-fleshed and white-fleshed varieties mixed together in the orchard, such as 1 row of white-fleshed varieties interplanted among every 2 rows of red-fleshed varieties. On the other hand, if it rains continuously during the flowering period, especially if rain begins in the evening (dragon fruit flowers generally begin to open 1-1.5 hours before sunset, fully open at sunset, and the corolla gradually closes at dawn, withering around sunrise), excessive rainwater will reduce or nullify the ejection capacity of the male anthers, and greatly reduce the receptivity of the female stigma, having a major impact on pollination and fertilization. On yet another hand, flower buds sprouting from the same stem node usually number 3-5, but after natural thinning they will usually retain 1-2 on their own, while the rest turn yellow and wither and drop off by themselves. However, after the flower buds sprout, if the orchard's moisture level fluctuates too much between dry and wet, the buds will also turn yellow and wither.
Dragon fruit growing conditions
Dragon fruit is a tropical plant. It likes light and tolerates shade, tolerates heat and drought, likes fertilizer and tolerates poor soil. Its stems can even grow attached to rocks. The plant has extremely strong wind resistance; as long as the support is sturdy it can withstand typhoons. Plant 300—400 plants per 667 sq m, with 1 cement post 20 cm square and 2 m tall buried in the middle of every 4 plants as a support. Dragon fruit can adapt to various soils, but neutral soil and slightly acidic soil rich in humus and good at retaining water and fertilizer are best. To make it grow vigorously after planting, more sterilized and fermented organic fertilizer from human, livestock and poultry manure must be applied. At the seedling stage, apply calcium magnesium phosphate fertilizer and compound fertilizer, with the amount depending on plant size.
Dragon fruit grows rapidly in a warm, humid environment with sufficient light. When cultivated in the open field in spring and summer, it should be watered more to keep its root system in a vigorous growth state. In continuous rainy weather, drainage should be carried out promptly to avoid infection by pathogens that causes stem and flesh rot. Dragon fruit tolerates low temperatures of 0°C and high temperatures of 40°C. To ensure year-round growth and multiple fruiting, try to reach the suitable temperature of 20—30°C. In northern regions, a greenhouse must be built, and the nighttime temperature in winter must not be lower than 8°C. In summer the plastic film may be left on, but ventilation is essential. The dragon fruit orchard does not need plowing; just remove weeds promptly. Dragon fruit has a thick waxy layer and a smooth appearance, requires no bagging, and saves labor and time. Dragon fruit generally has no pest problems; occasionally there may be nematodes in the roots and red spider mites on stems and leaves, which can be controlled promptly. From flowering to fruit maturity, dragon fruit takes about 30 days. When the fruit gradually turns from green to red, and the fruit is slightly fragrant and brightly colored, it can be harvested.
Propagation of dragon fruit
Seedlings grown from dragon fruit seeds can generally be planted directly. Because dragon fruit only blooms and fruits after the branches exceed 1 m in length, cutting seedlings or grafted seedlings are generally used for propagation and cultivation. Because cutting seedlings root easily, cutting seedlings are mostly used in production. However, yellow dragon fruit grows poorly from cuttings, and red-fleshed dragon fruit exhibits self-incompatibility in production. Therefore, for these two varieties, grafted seedlings should be used to improve quality and yield.
1. Cutting seedlings
Spring and summer are most suitable. For cuttings, choose fully grown stem nodes. Discarded branches cut off can still be used for cutting propagation. When cutting, cut the branches into 30 cm sections, place them in a cool place until the wounds air-dry, then insert them into a sand bed or directly plant them under the support frame and beside the cement posts. Except during frost periods, this can be done at any time. After cutting, no watering is needed; keep the soil dry. Begin watering after 10 days.
2. Grafted seedlings
Choose pest-free, robustly growing "Liangtianchi" (dragon fruit rootstock) with plump stem flesh as the rootstock, and graft on a sunny day. Cut the dragon fruit plant with a knife into 3-4 cm stem sections and wait for the wounds to dry. Cut a flat surface with a horizontal knife 10 cm up the rootstock stem, insert the scion, align the cambium, tie it firmly with cotton thread, and place it indoors for cultivation. At 28-30°C, after 4-5 days a large amount of callus tissue forms on the wound junction surface. If the color of the scion and rootstock is close, it indicates the vascular bundles of the two have healed and the grafting is successful. Then it can be moved into a temporary planting bed to continue cultivation.
3. Seedling stage management
The nursery bed should be in a ventilated and sunny place, in a field plot with fertile soil and convenient drainage and irrigation. Till finely and make beds; the bed with ditch should be 90 cm. Apply 1500-2000 kg of decomposed chicken manure or cow manure per mu, mix in 1000 kg of rice husk, stir evenly, and apply it during land preparation into the surface soil layer 10-30 cm below the bed surface. After that, apply 100-150 kg of calcium magnesium phosphate fertilizer, stir it evenly with a hoe, and apply it into the surface soil layer 4-5 cm deep. Then plant the small seedlings in the nursery bed at a spacing of 3 cm, and spray 500 times diluted carbendazim once. On sunny days, when the surface soil turns white, water as appropriate (about every 7-10 days). Apply 6 kg of compound fertilizer per mu every 14 days. Wait until stem sections with plump stem flesh are produced, then they can leave the nursery.
Field management of dragon fruit
Dragon fruit begins to bloom and fruit 12-14 months after planting, can bloom 12-15 times per year, with the fruiting period from April to November. The fruit matures 30-40 days after the flowers fade, with a single fruit weight of 500-1000 g. In the second year after planting, each post produces more than 20 fruits. In the third year it enters the full fruiting period. With a relatively high level of management, the yield can reach 2500 kg/667 sq m. Its high-yield cultivation key points are as follows:
1. Apply thin fertilizer frequently. Because the fruit harvest period is long, heavy organic fertilizer must be applied every year, and nitrogen, phosphorus and potassium compound fertilizer must be applied in a balanced way over the long term. During the flowering and fruiting period, potassium and magnesium fertilizer should be added to promote sugar accumulation in the fruit and improve quality. During the fruiting period, keep the soil moist, and cover the tree disc with grass or mushroom residue. In dry weather, irrigate once every 3-4 days.
2. Pinching. When the branches grow to 1.3-1.4 m long, pinch off the growing tips to promote branching and let the branches droop naturally.
3. Interplanting and artificial pollination. When planting dragon fruit, interplant about 10% white-fleshed dragon fruit. Mutual pollination between varieties can significantly increase the fruit-setting rate. If rainy weather occurs, artificial pollination should be carried out. Pollination can be done in the evening when the flowers open or in the early morning before the flowers close, using a brush to directly apply pollen onto the stigma of the female flower.
4. Pruning branches. After harvest each year, cut off the branches that have already borne fruit to let them send out new branches again, ensuring next year's yield.
5. Pest and disease control. Dragon fruit has relatively few pests and diseases. At the seedling stage it is susceptible to damage by snails and ants, which can be controlled with insecticides. In hot and humid seasons it is susceptible to diseases, with partial branch necrosis and mildew spots appearing, which can be controlled with triadimefon, strong copper oxide, etc., with good results.
From the above introduction, I believe that besides knowing dragon fruit is delicious, everyone now has a general understanding of its other aspects. In fact, growing dragon fruit is not a very simple matter; a lot of effort is required to eat the delicious fruit. So when we eat delicious dragon fruit, the first people we should thank are the friends who work hard to grow it.