Overview
Dioscorea retusa Mast. is a perennial plant belonging to the Dioscoreaceae family. This plant is commonly called the Cush Cush Yam.Origin and Distribution
The plant is native to the Caribbean and South America. It can now be found growing in various tropical regions worldwide.Common Names
The Cush Cush Yam is known by several common names including aerial potato, cush-cush yam, white yam, white elephant yam, and lauki.Appearance
The Cush Cush Yam is a climbing vine with a smooth stem that can grow up to 10 meters long. The leaves are heart-shaped and the yellow-green flowers are small and unremarkable. The plant produces corky, rough-textured, and elongated tubers that are usually 10-70 cm long. The tubers are oblong, curved, or cylindrical in shape with white flesh.Uses
The Cush Cush Yam is a popular food crop in many countries, especially in Africa and Asia. The tubers are used in a variety of dishes including stews, soups, and curries. The plant is also used for medicinal purposes. It has antimicrobial and anti-inflammatory properties and is used to treat wounds, fever, and respiratory infections. The Cush Cush Yam is also an important ingredient in traditional medicine practices. The plant's tuber extracts have been used to manage diabetes and liver diseases. Additionally, the plant's leaves are used as a vegetable in some cultures. It is a source of dietary fiber, protein, and vitamins, making it a nutritious addition to any diet.Light Requirements
Dioscorea retusa Mast. thrives in warm and humid environments. It requires a high amount of light for optimal growth and survival, but not direct sunlight. It is ideal for partial shade conditions, where the plant receives bright but indirect light.
Temperature Requirements
This plant grows best in warm temperatures, between 20°C and 30°C. It is intolerant to frost and cold weather, and its growth will be affected drastically if exposed to temperatures lower than 10°C.
Soil Requirements
The ideal soil for Dioscorea retusa Mast. is loose, well-draining, and moist. The pH range should be between 5.5 and 7.5. It is a nutrient-loving plant, and therefore requires soil that is rich in organic matter. It is sensitive to waterlogging and heavy clay soils, which can lead to root rot.
Cultivation methods for Dioscorea retusa Mast.
Dioscorea retusa Mast. is a perennial plant that requires a warm and humid climate to prosper. The best time to plant the yam is in Spring when the soil temperature is above 20°C. Before planting, it's important to ensure the soil is loamy, well-draining and rich in organic matter. The ideal soil pH ranges between 5.5 and 6.5. If the soil pH is too high or too low, amend the soil accordingly. The plant requires partial shade during the day and prefers sheltered places.
Watering needs of Dioscorea retusa Mast.
When it comes to watering, Dioscorea retusa Mast. prefers moist soil, but overwatering can lead to rotting of the tubers or cause stunted growth. During the first few weeks after planting, ensure the soil is moist but not waterlogged. Established plants can go for up to a week without watering unless the weather is extremely hot and dry. When watering, it's important to avoid splashing water on the leaves to prevent the spread of fungal diseases. Irrigation through drip or seepage irrigation is ideal.
Fertilization of Dioscorea retusa Mast.
The yam plant requires regular fertilization to promote healthy growth and development. Incorporate a balanced fertilizer that's rich in nitrogen, phosphorus, and potassium in the soil, just before planting. A nitrogen-rich fertilizer during the first few weeks of planting can promote the development of healthy foliage. Once the plant starts tuber formation, switch to a potassium-rich fertilizer to promote healthy tuber growth. Apply the fertilizer every two weeks during the growing phase and halt all application 4-6 weeks before harvest to allow the plant to harden off.
Pruning methods for Dioscorea retusa Mast.
Dioscorea retusa Mast. requires little pruning unless it's developed runners. One way to control runners is by planting the yam in mounds, which keep the runners from spreading far and wide. In case runners develop, cut them back to prevent the plant from spreading too much. It's also important to remove yellow and wilted leaves or those infested with pests and diseases since they can transmit infections to other parts of the plant. The pruning tools should be sterilized to prevent transferring diseases.
Propagation of Dioscorea retusa Mast.
Dioscorea retusa Mast. is commonly known as the Chinese yam and is a perennial herbaceous vine of the family Dioscoreaceae. The plant is native to East Asia, including Japan, Korea, and China. The plant has tuberous roots that are edible and widely consumed. Propagation of Dioscorea retusa Mast. can be done by seed, vegetative propagation, and micropropagation.
Seed propagation
The plant produces small, black, round seeds that are viable for up to one year. Seed propagation is the simplest and most economical method of propagation. To propagate by seeds, collect seeds from mature plants and store them in a cool, dry place. In the planting season, sow seeds in well-drained, moist soil at a depth of 1-2 cm. The germination rate is generally low and takes 3-4 weeks to germinate.
Vegetative propagation
Vegetative propagation is another popular method of propagating Dioscorea retusa Mast. The plant can be propagated vegetatively through tubers or stem cuttings. Vegetative propagation ensures that the offspring are identical to the parent and must be done carefully to avoid damage to the parent plant.
To propagate through tubers, select healthy and mature tubers and divide them into several small pieces, each with at least one bud. Plant the tuber pieces in well-drained soil and keep them moist. The tuber pieces will grow into new plants.
To propagate through stem cuttings, take cuttings from healthy and mature stems of the plant, ensuring that the cuttings are at least 10 cm long and have buds. Plant the cuttings in well-draining soil and keep them moist. The cuttings will develop roots and grow into new plants.
Micropropagation
Micropropagation is an advanced technique of plant propagation that involves growing plants from tiny pieces of tissue in a laboratory. This method is the most expensive but allows propagation of large numbers of plants with the same characteristics as the parent plant. The technique involves sterilizing the tissue and then growing it on a nutrient media with growth hormones until it develops into a plantlet. The plantlet is then transferred to soil to grow into a mature plant.
In conclusion, Dioscorea retusa Mast. can be propagated by seed, vegetative propagation, and micropropagation. The most common and traditional methods are seed and vegetative propagation, while micropropagation is an advanced and expensive technique with a higher success rate of producing plants with desirable traits.
Disease and Pest Management for Dioscorea Retusa Mast.
Dioscorea retusa Mast. is a tuberous plant that is commonly known as the Chinese yam. It is an important crop in many parts of Asia, known for its nutritious and medicinal properties. However, this plant is vulnerable to various diseases and pests that can lead to significant yield losses. Here are some of the common diseases and pests that might affect Dioscorea retusa Mast. and ways to manage them:
Common Diseases
Dioscorea Virus Diseases: This disease is caused by several viruses that can infect the yam leaves, stems, and tubers. The symptoms include stunted growth, yellowing of leaves, and discoloration of tubers. There is no cure for this disease, and infected plants should be removed and destroyed. Preventive measures include planting certified yam seeds, crop rotation, and controlling insect vectors.
Anthracnose: This disease is caused by the fungus Colletotrichum gloeosporioides, which infects the leaves and stems of yam plants. The symptoms include brown spots on leaves and stems, which can enlarge and cause the leaves to drop. The tubers may also be infected, resulting in discolored and rotting flesh. To manage this disease, remove and destroy infected plant debris, sanitize tools, use fungicides, and improve air circulation and drainage in the field.
Root Rot: Root rot is caused by several soil-borne fungal pathogens that attack the roots of yam plants. The symptoms include wilting, yellowing, and stunted growth of plants. In severe cases, the plants may die. To prevent root rot, avoid overwatering, improve soil drainage, and use fungicides.
Common Pests
Yam Beetles: Yam beetles are among the most destructive pests of Dioscorea retusa Mast. The larvae feed on the roots and tubers of yam plants, causing significant yield losses. The adult beetles also feed on the leaves and stems of the plants. To manage yam beetles, use pheromone traps, rotate crops, apply insecticides, and remove and destroy infested plant debris.
Nematodes: Plant-parasitic nematodes can attack the roots of yam plants, causing stunted growth and decreased yield. To manage nematode infestations, use resistant varieties, rotate crops, and apply nematicides.
Cutworms: Cutworms are larvae of several moth species that feed on the stems of yam plants, causing wilting and stem breaking. To manage cutworms, handpick and destroy the larvae, use insecticides, and improve soil drainage.
In conclusion, Dioscorea retusa Mast. is susceptible to various diseases and pests that can damage plant growth and yield. Proper management practices such as using certified seeds, crop rotation, sanitation, use of fungicides and insecticides, and biological control measures will help prevent and manage disease and pest outbreaks. Regular monitoring of the crop will allow for early detection and prompt corrective measures.
