Origin
The Dioscorea triphylla A.Rich. var. abyssinica R.Knuth, also known as the Ethiopian yam, is a plant species native to Ethiopia, Africa. It is commonly found in the highlands of Ethiopia.
Common Names
This plant species is commonly known as the Ethiopian yam and is referred to as "Engocha" in the Amharic language. It is also known as Tadi in Harar, another region in Ethiopia.
Uses
The Ethiopian yam is a highly nutritious plant that is widely consumed as a food source in Ethiopia. The tubers are rich in starch and are used in a variety of dishes, such as porridge and bread. The leaves of the plant are also eaten, cooked like spinach, and contain vitamins A and C.
Besides food, the plant has medicinal properties in Ethiopia, where it is used to treat ailments such as stomach upsets and infertility.
General Appearance
Dioscorea triphylla A.Rich. var. abyssinica R.Knuth is a perennial vine that grows up to 12 meters long. The leaves are alternate, heart-shaped, and have three lobes. The plant produces aerial bulbs that can weigh up to 40 kg and have a long, cylindrical, and tuberous appearance. The bulb's skin is brown, while the flesh is white or yellowish in color. The plant has small flowers that are yellowish-green in color, and the fruit is a capsule containing winged seeds.
Light Requirements
Dioscorea triphylla A.Rich. var. abyssinica R.Knuth requires full sunlight or partial shade to grow successfully. Direct sunlight is good for the plant's growth and productivity. The plant needs at least 6-8 hours of sunlight daily. However, it can tolerate partial shade as well.
Temperature Requirements
The Dioscorea triphylla A.Rich. var. abyssinica R.Knuth plant requires warm temperatures to grow. The ideal temperature range for the plant lies between 20 and 30°C. The plant is intolerant to frost and cannot survive in areas that receive frost or below freezing point temperatures.
Soil Requirements
The soil required for the cultivation of Dioscorea triphylla A.Rich. var. abyssinica R.Knuth plant must be well-drained, fertile, and rich in organic matter. The plant prefers a slightly acidic soil with a pH ranging from 5.5 to 6.5. The ideal soil type for the plant is clayey and loamy soil. However, the plant can also grow in sandy soil.
Cultivation methods
Dioscorea triphylla A.Rich. var. abyssinica R.Knuth, commonly known as Abyssinian yam, thrives in warm, humid climates. It prefers well-drained soils and a slightly acidic to neutral pH. The plant is propagated through vine cuttings or tubers.
When planting vine cuttings, they should be placed in a horizontal position, and only the top part should be visible. Tubers, on the other hand, should be planted with the pointed end facing up and covered with about 5 cm of soil.
The plant should be grown in a sunny location initially, and the young vines must be supported with stakes until they can stand on their own.
Watering needs
Abyssinian yam requires adequate moisture to grow well. The plant should be watered frequently during the dry season or when rainfall is insufficient. Overwatering, however, can lead to the development of fungal diseases. It is, therefore, essential to maintain a balance and allow the soil to dry out slightly before the next watering.
Fertilization
Applying organic matter, such as compost and well-rotted manure, can improve the soil's fertility and increase the yield of the plant. Fertilizers rich in nitrogen, phosphorus and potassium can also be applied at planting, during flowering and towards the end of the growing season. It's important to follow the instructions on the fertilizer packaging and not over-fertilize, as this can cause damage to the plant.
Pruning
Pruning Abyssinian yam is essential to increase the yield, remove dead or diseased parts and to prevent overcrowding. Vines that have produced tubers should be cut back to the ground level after harvesting. Pruning during the growing season should also be carried out to train the plant, remove weak or damaged vines and encourage the growth of healthy ones.
Propagation of Dioscorea triphylla A.Rich. var. abyssinica R.Knuth
Dioscorea triphylla A.Rich. var. abyssinica R.Knuth is commonly propagated through vegetative means. The most common method used is through stem cuttings. Cuttings should be taken from the parent plant during the dormant season, preferably from mature, woody stems.
The cutting should be at least 8 inches in length and should have at least 2-3 nodes. Remove any leaves from the lower nodes and dip the cut end in a rooting hormone to encourage rooting. The cutting can then be planted in a well-draining soil mixture, with the bottom node buried in the soil.
The cutting should be watered frequently until established and kept in a warm, humid environment to encourage root growth. Transplant the rooted cuttings into individual pots or directly into the field after the last frost.
Another method of propagation for Dioscorea triphylla A.Rich. var. abyssinica R.Knuth is through tuber division. This method involves dividing the parent tuber into smaller sections, each with a bud or eye. These smaller tubers can then be planted in well-draining soil and kept moist until established.
It is important to note that Dioscorea triphylla A.Rich. var. abyssinica R.Knuth can take up to several years to mature, so patience is key when propagating this plant.
Disease and Pest Management for Dioscorea triphylla A.Rich. var. abyssinica R.Knuth
Dioscorea triphylla A.Rich. var. abyssinica R.Knuth, commonly known as Abyssinian yam, is a climbing plant widely grown for its edible root tubers. However, like other crops, Abyssinian yam is susceptible to several diseases and pests that can significantly reduce its yield and quality. To ensure optimal production, it is essential to adopt proper disease and pest management practices.
Common Diseases
One of the primary diseases that affect Abyssinian yam is anthracnose. This fungal disease is characterized by the development of small, sunken spots on the leaves and stems, which later expand and merge, causing the affected parts to wither and die. The best strategy to manage anthracnose is to remove infected leaves and stems and spray the plant with a fungicide, such as copper-based products or mancozeb.
Another disease that affects Abyssinian yam is powdery mildew. This fungal disease appears as white powdery spots on the leaves and stems, which can reduce the photosynthetic activity of the plant. To manage powdery mildew, it is advisable to remove infected leaves and apply a fungicide, such as sulfur or potassium bicarbonate, to prevent the spread of the disease.
Common Pests
Besides diseases, Abyssinian yam is also prone to attack by several pests, including yam tuber beetles, aphids, and nematodes. Yam tuber beetles are the most destructive pests, causing considerable damage to the root tubers, thereby reducing the yield and quality of the crop. To manage yam tuber beetles, it is essential to use insecticides, such as carbaryl or pyrethroids, and adopt cultural practices, such as crop rotation and the use of certified seeds.
Aphids are another pest that can attack Abyssinian yam. These tiny insects suck the sap from the leaves and stems, resulting in stunted growth and the curling of leaves. To manage aphids, it is advisable to use insecticides, such as neem oil or insecticidal soaps, and to encourage the presence of natural enemies, such as ladybugs and lacewings, which feed on aphids.
Nematodes are also a common pest that affects Abyssinian yam. These microscopic worms live in the soil, where they feed on the roots of the plant, causing stunted growth and reduced yield. To manage nematodes, it is advisable to use nematicides, such as carbofuran or fumigants, and to adopt cultural practices, such as crop rotation, soil solarization, and the use of resistant varieties.
Overall, effective disease and pest management practices are crucial for the optimal production of Abyssinian yam. By adopting a combination of cultural, biological, and chemical control measures, farmers can minimize the impact of diseases and pests, enhance the quality of the crop, and improve their yield and income.
