Origin
Dioscorea cayenensis Lam. var. praehensilis (Benth.) A.Chev. is a type of yam plant that belongs to the family Dioscoreaceae. It is a native of West Africa, specifically in countries such as Cameroon, Nigeria, Ghana, and Sierra Leone.
Common Names
This plant is commonly known as the Guinea yam and is regarded as one of the most important food crops in West Africa. Largely cultivated in the savannah area of the continent, it is also known locally as "Njama" or "Kpon gbo."
Uses
The Guinea yam is a staple food in many African countries, with its tubers serving as a valuable source of carbohydrates and proteins. It is often prepared by boiling, roasting, or frying, and used in dishes such as stews, soups, and porridges. The leaves of the Guinea yam are also edible and can be used as a vegetable. Apart from its food value, the Guinea yam is also used in traditional medicine to treat various ailments such as malaria, diabetes, and hypertension. Its extracts have been shown to possess antifungal and antibacterial properties and may potentially be used to develop new drugs. In addition to its agricultural and medicinal uses, the Guinea yam also plays an important role in the cultural and social life in West Africa. It is often used in religious ceremonies and festivals and is regarded as a symbol of wealth and prosperity.
General Appearance
Dioscorea cayenensis Lam. var. praehensilis (Benth.) A.Chev. is a climbing vine that can grow up to 5 meters in length. It has heart-shaped leaves that are alternate, lobed, and can grow up to 20 cm in length. The plant produces underground tubers that can weigh up to 20 kg and are long, cylindrical, and covered in a rough, brown skin.
Light Requirements
The plant Dioscorea cayenensis Lam. var. praehensilis (Benth.) A.Chev. requires bright light to grow. It is an ideal plant to grow in areas where it can receive full sun for at least six hours a day. In the absence of full sun, the plant can also thrive in areas that receive partial sunlight.
Temperature Requirements
The plant requires warm temperatures to survive. The ideal temperature range for the plant is between 21°C and 28°C. The plant cannot tolerate low temperatures and should be protected from frost at all times. The plant requires humid conditions, and the humidity levels should be maintained between 60% and 90%.
Soil Requirements
The plant grows well in well-drained, fertile soil. The soil should be rich in organic matter and should have a pH range of 6.0 to 7.0. The addition of organic matter to the soil can enhance the soil's water-holding capacity and improve the plant's growth. The plant does not tolerate waterlogged soil or soils that are too dry.
Cultivation
Dioscorea cayenensis Lam. var. praehensilis (Benth.) A.Chev can be propagated by tubers, whose sprouts emerge from buds called "eyes." The plant is typically grown in tropical regions and requires a warm, humid climate to thrive. The ideal soil for cultivation is fertile, well-drained, and rich in organic matter.
Watering Needs
The plant requires regular watering during the growing season to ensure that the soil remains moist. However, it is essential to avoid overwatering, as excessive moisture can lead to root rot and other fungal diseases. In water-deficient areas, irrigation systems can be set up to maintain optimal soil moisture levels.
Fertilization
Fertilizers rich in nitrogen, phosphorus, and potassium are ideal for growing Dioscorea cayenensis Lam. var. praehensilis (Benth.) A.Chev. The fertilizer should be applied in the early stages of growth to boost the development of the plant. Moreover, applying a dilute solution of fertilizer on the leaves can help to supplement the nutrients in the soil.
Pruning
Pruning is not a critical aspect of growing Dioscorea cayenensis Lam. var. praehensilis (Benth.) A.Chev. However, it is essential to remove dead and diseased foliage regularly to prevent the spread of disease to the rest of the plant. Removing the infected parts helps to keep the plant healthy and allows the remaining parts to continue growing.
Propagation of Dioscorea cayenensis Lam. var. praehensilis (Benth.) A.Chev.
Dioscorea cayenensis Lam. var. praehensilis (Benth.) A.Chev. can be propagated vegetatively through tubers and stem cuttings.
Tuber propagation
The most common and successful method of propagating D. cayenensis is through tubers. The tubers should be selected from healthy plants that are at least one-year-old. The selected tubers are planted into the soil, usually in mounds or ridges, with the sprout facing up. The planting depth should be about 5-10cm. Tuber planting is typically done at the beginning of the rainy season. New plants will emerge within 2-3 weeks after planting.
Stem cutting propagation
Propagation through stem cuttings is another option for D. cayenensis. Select healthy stems that are at least one year old and remove a section of about 20-25cm in length. Cuttings are typically taken from the middle part of the stem. These stem cuttings should be planted into the soil horizontally, with one end just below the soil surface. Cuttings are usually planted in the early rainy season. The cuttings will develop roots and shoots within 2-4 weeks of planting.
Disease Management
Dioscorea cayenensis Lam. var. praehensilis (Benth.) A.Chev. is susceptible to various diseases that affect its yield and quality. Some common diseases and their management strategies are discussed below:
Anthracnose
Anthracnose is a fungal disease that causes dark, sunken lesion on leaves, stems, and fruits of Dioscorea cayenensis. The disease is most severe in warm, humid conditions. To manage anthracnose, it is important to avoid wounding the plant during cultivation, harvest, and handling. Crop rotation, removal of infected plant debris, and use of resistant varieties can also help control the disease. Application of fungicides may be necessary in severe cases.
Fusarium Wilt
Fusarium wilt is a fungal disease that causes wilting and yellowing of leaves, stunted growth, and eventually plant death. The disease is most severe in warm, moist soil. To manage Fusarium wilt, it is important to practice crop rotation, avoid overwatering, and use disease-free planting material. Application of fungicides may be necessary in severe cases.
Root Rots
Root rots are caused by various fungi and bacteria that infect the roots of Dioscorea cayenensis. Infected plants show yellowing, wilting, and stunted growth. To manage root rots, it is important to improve soil drainage, avoid overwatering, and use disease-free planting material. Application of fungicides or bactericides may be necessary in severe cases.
Pest Management
Dioscorea cayenensis Lam. var. praehensilis (Benth.) A.Chev. is also susceptible to various pests that can cause damage to the plant. Some common pests and their management strategies are discussed below:
Yam tuber beetles
Yam tuber beetles cause damage to the tubers of Dioscorea cayenensis, reducing their yield and quality. These pests can be controlled through cultural methods such as clearing the fields of weeds, crop rotation, and careful cultivation practices. Application of insecticides may also be necessary.
Yam nematode
The yam nematode is a microscopic worm that infects the roots of Dioscorea cayenensis, causing stunted growth and decreased yield. To manage yam nematode, it is important to use disease-free planting material, practice crop rotation, and improve soil health. Application of nematicides may also be necessary in severe cases.
Yam scale insects
Yam scale insects are sap-sucking pests that cause yellowing and stunted growth of Dioscorea cayenensis. These pests can be controlled through cultural methods such as removing infested plant debris, cultivating the soil, and applying insecticides.
