Introduction
Dioscorea composita Hemsley is a plant species that belongs to the Dioscoreaceae family, commonly known as composite yam or Chinese yam. This perennial vine is primarily found in China but also grows in neighboring countries such as Vietnam and Taiwan. This plant has various uses, including food and traditional medicine, owing to its high nutritional value and therapeutic properties.
Appearance
The composite yam is a fast-growing, vigorous, and twining vine that can grow up to 4 meters in height. The plant has broad and hastate heart-shaped leaves with a long petiole. The leaves measure approximately 5-18 cm long and 4-16 cm wide; new leaves have a dense pubescence on both sides. The plant produces small, inconspicuous, and greenish-yellow flowers arranged in loose panicles. The fruit is a three-angled capsule, 1-1.5 cm long, containing winged seeds.
Uses
Composite yam has multiple uses, including therapeutic and culinary. In traditional Chinese medicine, composite yam is believed to tonify lung qi and nourish the spleen and kidney yin. The plant has potential antitumor, immunomodulatory, and anti-inflammatory properties. Its high concentration of diosgenin, a phytoestrogen, is used for the synthesis of steroid hormones such as progesterone and testosterone. Composite yam is also widely used in Chinese cuisine, particularly in stir-fries, stews, and soups. The yam is cooked and consumed as a vegetable and is a good source of vitamins, minerals, and dietary fiber.
Conclusion
Dioscorea composita Hemsley, commonly known as composite yam, is a perennial vine found in China, Vietnam, and Taiwan. The plant has broad heart-shaped leaves, greenish-yellow flowers, and three-angled capsules. Composite yam has multiple uses, including traditional medicine and culinary applications, owing to its high nutritional value and therapeutic properties.
Light Requirements
Dioscorea composita is a plant that requires bright light but should be protected from direct sunlight, especially during the hottest parts of the day. Therefore, it is best to place the plant in a location with filtered light or partial shade.
Temperature Requirements
This plant requires warm temperatures to thrive, with the ideal temperature range being between 22 and 28 degrees Celsius. However, it can tolerate temperatures as low as 16 degrees Celsius and as high as 35 degrees Celsius. It is therefore important to keep the plant in a location with consistent temperatures, away from drafts or sudden temperature changes.
Soil Requirements
The Dioscorea composita prefers a well-draining soil mix that is rich in organic matter. A pH range of 5.5 to 6.5 is most suitable for this plant. It is important to avoid waterlogged soil, as this can lead to root rot. Adding perlite or sand to the soil mix can increase drainage and prevent waterlogging.
Cultivation Methods for Dioscorea composita Hemsley
The best way to cultivate Dioscorea composita Hemsley is by planting the tubers in well-draining soil with a pH range of 6.0 to 6.5. The soil should be prepared by loosening it up to 60 cm deep to allow deep rooting and give the plant enough room to grow. Dioscorea composita Hemsley tuber should be planted 10-15 cm deep, with sprouts pointing upwards, and then covered with soil. The plant should be grown in full sun or partially shaded areas to thrive.
Watering Needs for Dioscorea composita Hemsley
Dioscorea composita Hemsley should be watered frequently during the growing season. This plant requires moist soil but shouldn't be left in standing water. Watering should be done early in the morning or late in the evening to avoid evaporation. The amount of water should be monitored to ensure that the soil doesn't dry out, and the plant doesn't get water-logged.
Fertilization for Dioscorea composita Hemsley
Dioscorea composita Hemsley should be fertilized with a balanced fertilizer, rich in nitrogen, phosphorus, and potassium. Fertilization should be done twice a year, in early spring and mid-summer. The amount of fertilizer to use should be based on the soil test results and the age of the plant. Younger plants require less fertilizer than older plants. Over-fertilization should be avoided to prevent the buildup of salts in the soil, which can lead to plant damage.
Pruning for Dioscorea composita Hemsley
Pruning of Dioscorea composita Hemsley should be done to control its growth and shape. Pruning should be done in late winter, just before the plant starts growing. The plant should be pruned to remove the dead or diseased stems, and to direct its growth towards the desired direction. Any excessive shoots should be removed to allow the plant to focus its energy on the healthy growth of the remaining stems. Pruning should be done carefully to prevent damage to the remaining stems or the entire plant.
Propagation of Dioscorea composita Hemsley
Dioscorea composita Hemsley, also known as Chinese yam, is a fast-growing and perennial plant that can propagate through both vegetative and sexual methods. The following are the different ways to propagate Dioscorea composita Hemsley:
Via tubers
The most common propagation method of Dioscorea composita Hemsley is through its tubers. These tubers are found underground, and they can be harvested during the dormant season of the plant. To propagate via tubers, the following steps should be taken:
- Harvest the tubers during dormancy
- Choose tubers that are healthy and disease-free
- Cut the tubers into sections, ensuring that each section has at least one bud or eye
- Plant the sections in a well-draining soil, ensuring that the buds are facing upwards
- Water the sections well, and keep the soil moist until new shoots emerge
Via bulbils
Dioscorea composita Hemsley can also propagate via bulbils, which are small aerial bulbs that grow on the stem of the plant. To propagate via bulbils, the following steps should be taken:
- Remove the bulbils from the stem of the plant during their dormant period
- Plant the bulbils in a well-draining soil, ensuring that the flat side of the bulbil is facing downwards
- Water the bulbils, and keep the soil moist until new shoots emerge
Via seeds
Propagation of Dioscorea composita Hemsley via seeds is not common, but it is still a viable option. To propagate via seeds, the following steps should be taken:
- Collect mature seeds from the plant during the fruiting stage
- Clean the seeds, and soak them in warm water for 24 hours
- Plant the seeds in a well-draining soil, ensuring that they are not buried too deep
- Water the soil and keep it moist until the seeds germinate
Disease Management
Dioscorea composita Hemsley is usually affected by fungal diseases that can significantly reduce its yield and quality. The most common fungal diseases that affect the plant include anthracnose, stem rot, powdery mildew, and rust.
To manage anthracnose, ensure that you use certified disease-free seeds or treat the seeds with a fungicide before planting. Prune affected plant parts and destroy them to prevent further spread of the disease, and apply a fungicide to control the disease.
Stem rot can be managed by avoiding overwatering and providing adequate drainage for the plant. Also, remove infected plant parts and dispose of them. Apply a fungicide to control the disease.
Powdery mildew can be controlled by ensuring proper air circulation around the plant, avoiding overhead irrigation, and applying a fungicide. Remove and destroy heavily infected plant parts to reduce further spread of the disease.
Finally, rust can be managed by removing infected plant parts and spraying the plant with a fungicide.
Pest Management
Dioscorea composita Hemsley is also susceptible to pest attacks, which may cause significant damage to the plant if not managed in time. Some of the common pests that affect the plant include mealybugs, aphids, and spider mites.
To manage mealybugs, use insecticidal soap or horticultural oils to suffocate the mealybugs. You can also remove them manually using a cotton swab dipped in rubbing alcohol.
Aphids can be controlled by introducing natural predators such as ladybugs or by treating the plant with an insecticidal soap.
Spider mites can be managed by keeping the plant well-irrigated to discourage the mites from infesting it. Also, spray the plant with insecticidal soap or horticultural oils to control the mites.
In general, practicing good sanitation and cultural practices can help prevent pest and disease attacks while promoting plant health. This includes removing and destroying infected plant parts, monitoring the plant regularly for signs of pest and disease damage, and ensuring proper irrigation and fertilization of the plant.
