Overview
Dioscorea natalensis Engl., also known as the Natal yam, is a flowering plant from the Dioscoreaceae family. It is native to southern Africa and can be found in countries such as South Africa, Mozambique, and Zimbabwe.
Description
The Dioscorea natalensis is a climbing plant that can grow up to 10 meters long. It has a fleshy, tuberous root system that is used for propagation and as a food source. The leaves are large and heart-shaped, and the flowers are small, greenish-yellow, and appear in clusters.
Uses
The tubers of the Dioscorea natalensis are edible and are commonly consumed in parts of southern Africa. They are high in starch and are often boiled, steamed, or roasted. The plant also has medicinal uses, as the tubers and roots are believed to have anti-inflammatory, antioxidant, and antimicrobial properties. Additionally, the plant is used in traditional medicine to treat conditions such as coughs, colds, and fever.
Common Names
The Dioscorea natalensis is known by several common names, depending on the region. In South Africa, it is commonly referred to as the Natal yam or umthi. In Zimbabwe, it is known as the Mutsva, and in Mozambique, it is called Marara.
Light Requirements
Dioscorea natalensis Engl. requires full sunlight exposure in order to grow healthily. As this plant originates from warm regions, it has adapted to be able to withstand direct sunlight. Therefore, it must be grown in a location with at least 6-8 hours of sunlight per day.
Temperature Requirements
The optimal temperature range for Dioscorea natalensis Engl. growth is between 20-30°C (68-86°F). Extreme cold temperatures can lead to plant damage and even death. It is important to protect the plant from sudden temperature drops by using mulch or other protective materials during frosty weather.
Soil Requirements
The plant prefers well-draining, loamy soil. It should be kept slightly moist but not soaking wet, as this can lead to root rot. The soil pH should be slightly acidic, between 5.5-6.5. Organic matter can be added to the soil to help improve soil texture and fertility.
Cultivation Methods
The Dioscorea natalensis Engl. plant thrives in tropical and subtropical regions with a consistent supply of water. Plan for irrigation systems in regions with infrequent rainfall. It grows best in well-drained sandy loam soil with a pH between 6.0 and 6.5. The roots tend to grow deep into the soil, so prepare a hole deep and wide enough to accommodate them. The holes should be 1m apart to allow the vines to spread.
Watering Needs
Dioscorea natalensis Engl. plants require plenty of water to yield desirable tubers. The plants require well-drained soil because waterlogged soil can cause root rot. For optimal growth, the plants require frequent watering but avoid flooding the plants. Watering in the morning or evening when the sun is not that hot is recommended.
Fertilization
Regular fertilization is necessary to encourage the growth of a tuberous root. At planting, add compost, organic matter, or manure to the soil to help with moisture retention and nutrient supply. Three months after planting, fertilize the plants with nitrogen-based fertilizer to promote leafy growth. Before flowering, apply phosphorus, and after flowering, apply potassium-based fertilizers to encourage tuber growth.
Pruning
Dioscorea natalensis Engl. plants require pruning to encourage the growth of new leaves and tubers. After the vines reach 1.5-2m in length, prune the tips to encourage the growth of side shoots, or lateral branches. Pruning also helps to control the plant size and ensures adequate spacing for the healthy growth of each plant. Remove any damaged or diseased leaves regularly.
Propagation of Dioscorea Natalensis Engl.
Dioscorea natalensis Engl. is a perennial vine that can be propagated by both vegetative and sexual means. The plant has large, bulbous, underground tubers from where new plants are formed through various propagation methods.
Sexual Propagation
The sexual propagation of Dioscorea Natalensis Engl. is done through the collection of seeds. The vine forms small, greenish-yellow flowers that ripen into seedpods. When the pod turns brown, it is an indication that the seeds are mature and can be harvested. The seedpods are collected and dried under shade to prevent cracking and ensure that the seeds are viable. Once dried, they can be sown in soil or placed in water for germination.
Vegetative Propagation
Dioscorea natalensis can be propagated vegetatively using stem cuttings, tuber cuttings, and bulbils. For stem cuttings, a 2-3 node cutting is taken from the plant, and the lower leaves are removed. The cutting is then planted in a potting mix and watered to stimulate root growth. Tuber cuttings involve taking a small section of the tuber, which is cut into pieces with nodes and planted on its side in a potting mix. Bulbils are small plantlets that form on the base of the underground tuber. These can be carefully removed and planted in a potting mix.
The best time to propagate Dioscorea natalensis is during early summer. Growers can use a rooting hormone on the cuttings to enhance the rooting process. The cuttings or bulbils should be kept moist and in partial shade until they have established roots. They can then be transplanted to individual pots or directly into the garden.
Disease and Pest Management for Dioscorea natalensis Engl.
Dioscorea natalensis Engl., commonly known as the Natal yam, is a species of yam native to southern Africa, where it is an important food crop. As with all plants, the Natal yam is vulnerable to various pests and diseases, which can severely affect its growth and productivity. Proper disease and pest management practices can help minimize the damage caused by these factors.
Common Diseases
Some of the common diseases that can affect Dioscorea natalensis Engl. include:
- Yam Mosaic Virus: A viral disease that causes mottled leaves and a reduction in yield. Infected plants should be removed and destroyed to prevent the spread of the virus.
- Anthracnose: A fungal disease that causes lesions on the leaves, stems, and fruits of the plant. Infected plant parts should be removed and destroyed to prevent the spread of the disease.
- Fusarium Yellows: A fungal disease that causes yellowing and wilting of the leaves, as well as stunted growth. Infected plants should be removed and destroyed to prevent the spread of the disease.
Pest Management
Various pests can also cause damage to Dioscorea natalensis Engl. Some of the common pests include:
- Yam Beetle: This beetle feeds on the leaves and stems of the plant, causing defoliation and reduced growth. Insecticidal sprays can be used to control the beetle population.
- Yam Mite: This mite feeds on the undersides of the leaves, causing yellowing and a reduction in photosynthesis. The use of acaricides can help control the mite population.
- Yam Tubers Beetle: This beetle feeds on the yam tubers, causing damage to the crop. Proper storage of the tubers can help prevent infestations.
Other practices that can help manage pests and diseases include crop rotation, proper sanitation, and the use of resistant cultivars. It is also important to regularly inspect the crop for any signs of infestation or disease, and take appropriate measures to control or prevent any issues.
