Origin
Dioscorea buchananii Benth. is a climbing vine that belongs to the family Dioscoreaceae. It is native to West Africa, specifically in Nigeria, Sierra Leone, Liberia, and Ghana.
Common Names
The plant is commonly known as Buchanan's yam or just Buchanan in some regions. In Nigeria, it is called "Isu Buchanani" in Yoruba and "Ukokor" in Igbo. In Sierra Leone, it is known as "Kainkain" in Krio and "Tua" in Mende.
Uses
The tubers of Dioscorea buchananii Benth. are a staple food in West Africa. It is a good source of carbohydrates, dietary fiber, potassium, and vitamin C. The tubers can be boiled, fried, or roasted and used to make various dishes such as yam fries, yam porridge, pounded yam, and yam cakes.
The plant is also used for medicinal purposes in traditional African medicine. The tubers are believed to have anti-inflammatory and antidiabetic properties. They are used to treat various ailments such as arthritis, rheumatism, and diabetes.
General Appearance
Dioscorea buchananii Benth. is a climbing vine that can grow up to 10 meters in length. It has a woody stem and heart-shaped leaves that are about 10-15 cm in length. The plant produces tubers that can weigh up to 2 kg each. The tubers are cylindrical in shape and have a brown, rough, and scaly outer skin. The inner flesh is white and can have a slightly sweet taste.
The plant produces small greenish-white flowers that are male and female, but they are not often visible. The fruit produced by the plant is a capsule that contains winged seeds.
Light requirements
Dioscorea buchananii Benth. grows best in full to partial sunlight. It requires at least six hours of sunlight per day to thrive and produce healthy foliage. If grown in too much shade, the plant may become weak and susceptible to pests and diseases.
Temperature requirements
This plant prefers warm and humid climates. Temperatures between 20 to 30°C (68 to 86°F) are ideal for optimum growth and development. However, it can tolerate a range of temperatures between 5 to 40°C (41 to 104°F) as long as it's not for prolonged periods.
Soil requirements
The plant requires well-draining soil to ensure proper root growth and prevent waterlogging. A sandy loam soil or light clay soil is ideal. The soil pH range required by the plant is 5.0 to 7.5. The plant can tolerate acidic and slightly alkaline soils.
The soil should be rich in organic matter, and the addition of compost or aged manure is beneficial. Ensure that the soil is kept moist but not waterlogged. Overwatering can lead to root rot and other fungal diseases.
Cultivation Methods for Dioscorea buchananii Benth.
Dioscorea buchananii Benth. can be cultivated in warm and humid conditions. It grows well in well-drained soil that has a high organic matter content. Ideally, the plant should be grown in slightly acidic to neutral soils, with a pH level ranging from 5.5 to 7.0. The planting bed should be deep and well-tilled to allow the plant's roots to grow deeply and avoid potential nutrient competition with weeds.
Watering Needs for Dioscorea buchananii Benth.
Dioscorea buchananii Benth. requires regular watering to maintain its growth. The plant should be watered frequently during dry periods, but the soil should not be waterlogged as that might lead to root rot. For best results, it is recommended to water the plant deeply once or twice a week, allowing the soil to dry out slightly between waterings. Mulching around the base of the plant can help retain moisture and minimize watering needs.
Fertilization of Dioscorea buchananii Benth.
To promote optimal growth, regular fertilization is necessary. Fertilizers containing nitrogen, phosphorus, and potassium in a balanced ratio can be applied to the plant. The application should be in a ratio of 4:2:2 or 4:3:3. Fertilization should ideally be done 4 times a year starting from the planting date. To avoid fertilizer burn, it is recommended that the fertilizer be applied to the soil surface and not directly on the plant's base or leaves.
Pruning of Dioscorea buchananii Benth.
Pruning Dioscorea buchananii Benth. is generally not necessary, but the removal of dead, damaged, or diseased leaves and branches is recommended. Regular pruning can help promote better air circulation and sunlight penetration, leading to healthier plants. Care should be taken only to remove the affected parts and not damage the healthy ones. Pruning should be done using sharp, sterilized tools to minimize the spread of disease.
Propagation of Dioscorea buchananii Benth.
Dioscorea buchananii Benth., commonly known as Buchanan's yam, is propagated through various methods.
Sexual Propagation
The plant is dioecious, which means that it has separate male and female flowers. Sexual reproduction involves pollinating the female flowers with the pollen from the male flowers. The fruit produced by the female flowers contains several seeds that can be used for propagation. The seeds should be sown immediately after harvesting as they lose viability quickly. The seeds are sown at a depth of 5-7 cm and take about 2-3 weeks to germinate.
Asexual Propagation
Asexual propagation is preferred for Dioscorea buchananii Benth. since the offspring produced is true to the parent and does not exhibit any variation. The plant can be propagated through the following methods:
Cutting Propagation
Cuttings of 20-30 cm length and 2-3 cm diameter can be taken from the parent plant during the dormant season. The cuttings are planted vertically in soil-filled polybags or pots and kept in a shaded area. The cutting develops roots and shoots in 2-3 weeks and can be transplanted into the main field after 3-4 months.
Tuber Propagation
The tubers are cut into smaller pieces of 100-150 g each with at least one bud. The cut surfaces are dusted with fungicide powder to prevent rotting. The pieces are planted horizontally in trenches at a depth of 5-7 cm with the buds facing upwards. The trenches are covered with soil and mulched with dry straw to retain moisture. The tubers sprout within 1-2 weeks and are ready for transplanting after 2-3 months.
Propagation of Dioscorea buchananii Benth. is a critical aspect of commercial cultivation. By following the appropriate propagation methods, healthy and robust plants can be obtained, which ensures better yield and quality of yams.
Disease and Pest Management of Dioscorea buchananii Benth.
Dioscorea buchananii Benth., commonly known as Buchanan's yam, is a staple food crop in many African countries. Like any crop, yams are susceptible to diseases and pests that can damage crop yield and quality. Therefore, it is important to have an effective management plan for disease and pest control.
Common diseases
The common diseases that affect Dioscorea buchananii Benth. are black rot, anthracnose, and powdery mildew. Black rot is a fungal disease that causes black, sunken spots on the leaves, stems, and tubers. Anthracnose is also a fungal disease, causing lesions on the leaves and tubers, leading to rot and wilting. Powdery mildew is a fungal disease that causes a white powdery growth on the leaves, reducing photosynthetic capacity and yield.
To combat these diseases, yam farmers should plant disease-resistant varieties, maintain good hygiene practices such as removing infected plant parts, and spraying fungicides. Fungicides such as copper oxychloride, mancozeb, and carbendazim are effective in controlling fungal diseases in yams.
Common pests
The common pests that affect Dioscorea buchananii Benth. are rodents, nematodes, and yam beetles. Rodents such as rats and mice feed on the tubers, causing severe damage to the crop. Nematodes are microscopic worms that feed on the roots, causing stunted growth and reduced yield. Yam beetles feed on the leaves and stems, causing defoliation and reduced photosynthetic capacity.
Effective management of these pests involves employing cultural practices such as crop rotation, planting resistant varieties, and practicing field sanitation. The use of biopesticides such as neem product and the application of chemical pesticides like carbofuran is also effective in controlling pest infestations.
In conclusion, Dioscorea buchananii Benth. is a valuable crop that is susceptible to diseases and pests. Proper disease and pest management practices are essential to ensure a healthy crop and bountiful yields.
