Origin and Common Names
Dioscorea buchananii Benth. var. ukamensis R.Knuth, commonly known as Ukam or Ukam yam, is a species of yam that is native to West Africa. It is found in countries such as Nigeria, Cameroon, and Chad.
Appearance
The Ukam yam is a perennial vine that can grow up to 10 meters long. It has a smooth, cylindrical stem that can reach a thickness of up to 10cm in diameter. The leaves are heart-shaped with a glossy green color and can grow up to 25cm in length. The yam tuber is large, elongated and cylindrical with a brown, scaly exterior and reported to grow up to 2m long and 60cm in diameter.
Uses
Ukam yam is an important source of food across West Africa, particularly in Cameroon, where it serves as a staple food crop for many rural communities. Additionally, Ukam yam is known for its medicinal values such as improving metabolism, blood sugar levels, and digestion. It is also used in cosmetics industry for skin care products
Growth Conditions for Dioscorea buchananii Benth. var. ukamensis R.Knuth
Dioscorea buchananii Benth. var. ukamensis R.Knuth, commonly known as “Ukam” is a tuberous plant that is native to the tropical rainforest regions of Africa. The plant is an important source of food for the local people and has numerous medicinal properties, including the treatment of hypertension, diabetes, and asthma.
Light Requirements
The plant requires full sunlight to grow and flourish. It is recommended to grow it in a location that receives 6-8 hours of direct sunlight daily.
Temperature Requirements
The plant thrives in warm temperatures between 20°C to 35°C. Temperatures below 15°C can slow down the growth and development of the plant. The plant can withstand high temperatures but needs proper watering in such cases.
Soil Requirements
The plant grows well in well-drained soils that are rich in organic matter. It prefers soils with a pH of between 5.5 and 6.5. Sandy loam and clay loam soils are ideal for the plant. The soil must be deep enough, at least one meter or more, to ensure that the tubers can grow well.
In summary, planters should take note of these growth conditions when considering to plant the Dioscorea buchananii Benth. var. ukamensis R.Knuth. Full sunlight exposure, warm temperature not less than 20°C, and well-drained soils are essential to enable the plant to thrive and produce tubers suitable for consumption.
Cultivation Methods
Dioscorea buchananii Benth. var. ukamensis R.Knuth is a perennial plant that is propagated through the planting of tubers or through stem cuttings. For planting, select a site that has well-drained soil, receives plenty of sunlight, and is sheltered from strong winds. When planting, space the tubers or stem cuttings about 30cm apart and at a depth of 5-10cm. The plant requires some form of support, such as a trellis or a pole, for the vines to climb on and grow.
Watering Needs
The plant requires consistent watering to ensure it remains healthy and produces well. Water regularly, especially during the dry months, to keep the soil moist. Ensure that the plant does not sit in water as this can cause root rot. Watering should be reduced during the rainy season when the soil is already moist.
Fertilization
The plant requires regular fertilization to provide nutrients for optimal growth and tuber development. Fertilize at planting time, again after sprouting, and then every 3-4 weeks. Use organic fertilizers, such as chicken manure, compost, or milled bone, as these enrich the soil with necessary nutrients and improve soil texture. Avoid over-fertilization as this can lead to excessive vegetative growth and yield a poor harvest.
Pruning
Pruning the plant is important to encourage healthy foliage growth and promote tuber development. Begin by removing any weak or diseased vines, then select 3-4 strong vines to keep and remove the rest. Train these vines to climb on the trellis or pole, removing any shoots that are growing from the base of the plant or from the vine's axils. Pinch off the growing tips of the vines when they reach the top of the trellis or pole to encourage lateral branching and fuller foliage growth.
Propagation of Dioscorea buchananii Benth. var. ukamensis R.Knuth
Dioscorea buchananii Benth. var. ukamensis R.Knuth can be propagated through both sexual and asexual means, although propagation through seed is not commonly practiced due to the plant's long juvenile period before flowering (6-8 years). The most straightforward method for propagation is through the use of tubers.
Propagation through tubers
Propagation through tubers involves the division of mature tubers into smaller pieces intended for planting. It is important to only use disease-free, mature tubers for propagation, as using immature or diseased tubers can lead to poor yields and spread of diseases.
The process begins with digging up the mature tubers during the dormant season, which usually coincides with the end of the rainy season. The tubers are then cleaned and disinfected in fungicide to prevent fungal infections. The tubers are subsequently divided into smaller pieces, each of which should have at least one bud or "eye." These pieces are then planted horizontally in well-drained soil at a depth of 5-10 cm.
It is important to water the newly planted tubers thoroughly and keep them moist throughout the growing season. In humid regions, the newly planted tubers should be covered with a layer of mulch to keep the soil moist and prevent weed growth. New shoots should emerge in one to two weeks, and within six months, the new tubers should be ready for harvest.
Propagation through stem cuttings
In addition to propagation through tubers, Dioscorea buchananii Benth. var. ukamensis R.Knuth can also be propagated through stem cuttings. This method, however, is less common and less reliable than propagation through tubers.
To propagate through stem cuttings, select healthy, disease-free stems from mature plants. The stems should be cut into several 20-30 cm sections, with two to three nodes per section. The sections are then planted in moist, well-drained soil at a depth of 5-10 cm. The plants should be kept moist throughout the growing season, and new roots and shoots should emerge after two to three weeks. After six months, the new plant should be ready for transplanting to its permanent location.
Disease Management for Dioscorea buchananii Benth. var. ukamensis R.Knuth
Dioscorea buchananii Benth. var. ukamensis R.Knuth is a tropical vine that is prone to different types of diseases. Below are some common diseases that might affect the plant and ways to manage them:
Anthracnose
Anthracnose is a fungal disease that affects the vine's leaves, stems, and tubers. It causes small to large circular spots on the leaves, surrounded by a dark brown margin. The spots later become irregular in shape and merge, leading to defoliation and yield loss. To manage this disease, crops should be properly rotated to avoid soil-borne pathogens. Also, use resistant cultivars, remove and destroy infected plant residues, and apply copper-based fungicides during the early stages of the disease.
Black Spot
Black spot is a fungal disease that affects the leaves of the vine. It causes pale spots that become darker as the disease progresses. The spots also have a yellowish halo, and in severe cases, they join, leading to premature defoliation. To manage this disease, remove and destroy infected plant material, use resistant cultivars, and apply copper-based fungicides during the early stages of the disease.
Pest Management for Dioscorea buchananii Benth. var. ukamensis R.Knuth
Dioscorea buchananii Benth. var. ukamensis R.Knuth can also be affected by pests. Below are some common pests that might affect the plant and ways to manage them:
Yam Beetles
Yam beetles are the most common pests that affect the vine. They attack the plant's leaves, stems, and tubers, leading to yield loss. To manage these insects, employ cultural control measures like crop rotation, trapping them using light traps, and manually removing them from the crops. Use chemical control measures like applying neem-based insecticides, which are environmentally friendly, during the early stages of infestation.
Nematodes
Nematodes are roundworms that attack the roots of the vine, leading to poor growth and yield loss. To manage nematodes, ensure proper sanitation by removing and destroying crop residues, employ crop rotation, and use resistant cultivars. Also, apply organic soil amendments like compost and use chemical control measures like nematicide before planting.
