Origin
Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin is a type of edible yam that belongs to the family Dioscoreaceae. It is native to Africa, specifically Cameroon, Nigeria, and Gabon.
Common Names
Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin is commonly known as the forest yam, African yam, or bush yam. In Nigeria, it is known as “Isu oka” in Igbo, “Eleti” in Yoruba, and “Edda” in Efik.
Uses
The tuber of the Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin is highly nutritious and is a good source of carbohydrates, fiber, and essential minerals. It is often used in African cuisine as a staple food and is usually boiled, roasted, or mashed. The yam is also used in traditional medicine to treat various ailments such as rheumatism, diabetes, and stomach ulcers.
General Appearance
The Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin plant has twining stems that can grow up to 10 meters in length. The leaves are heart-shaped and exhibit a glossy, dark green appearance. The yam tubers vary in size and shape depending on the variety, with some reaching up to 1.5 meters in length and weighing up to 70 kilograms. The yam skin is usually rough and scaly, with a white, yellow or purple flesh inside.
Growth Conditions for Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin
Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin is a climbing plant commonly found in tropical African regions where it grows well under certain specific conditions.
Light Requirements
These plants grow well under the full sunlight exposures or partially shaded regions with sufficient sunlight. Therefore, it is essential to ensure that the plant gets enough sunlight exposure for healthy growth. Insufficient sunlight can lead to reduced growth or even death of the plant.
Temperature Requirements
Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin is a tropical plant and requires warm temperatures ranging from 23 to 28 degrees Celsius. However, these plants do not tolerate extreme temperatures, either hot or cold, and thrive well in moderate temperature ranges.
Soil Requirements
These plants require well-drained soils with adequate humidity to prevent waterlogging, which may lead to stunted growth, root rot, or even the death of the plant. They prefer soils that are rich in organic materials such as manure, compost, or any other natural fertilizers. Additionally, they require slightly acidic to neutral soils with a pH range ranging from 6.0 to 7.5.
Cultivation
Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin is a tropical vine that is tolerant of a range of conditions. It thrives in full sun or partial shade, and can be grown in well-draining soil or soil mixes. This vine can be propagated from stem cuttings, suckers, or tubers. The cuttings or suckers should be at least 20 cm long and should be rooted in a well-draining rooting medium before being transplanted to their final growing position.
Watering
This plant requires a consistent moisture level in the soil, but it should not be over watered. Overwatering can lead to root rot and the fungal infections. Water sparingly until the plant is established, and then water regularly, especially during the growing season. During the dry period, it is advisable to water twice a day.
Fertilization
Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin requires regular fertilization to ensure healthy growth. Use a balanced fertilizer that contains nitrogen, phosphorus, and potassium. Apply the fertilizer every two weeks or according to the instructions on the fertilizer package. Good quality compost can be used instead of fertilizer. Apply the compost around the base of the plant and mix it with the topsoil before watering.
Pruning
Pruning is necessary to keep the plant in check and to promote healthy growth. The plant should be pruned every year in late winter, before the new growth appears. Cut back any dead, diseased, or damaged stems, and remove any crossing or rubbing stems to prevent disease. If the plant is grown as a decorative plant. then the upper part can be cut back to about two-thirds of the main stem. This encourages new shoots from the base of the plant, which will produce more vigorous growth and more dense foliage.
Propagation of Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin
Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin can be propagated through both sexual and asexual means. The plant species has been observed to have both male and female reproductive organs, and the flowers are generally self-incompatible.
Sexual Propagation
Propagation of Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin through sexual means involves sowing seeds. Seeds are best sown in fall or early spring, and they require a period of stratification, either natural or artificial, to break dormancy. After stratification, the seeds can be sown in containers or directly on the ground. The soil should be well-draining and rich in organic matter. The ideal temperature range for germination is 20-30°C, and it can take up to two months for seeds to germinate.
Asexual Propagation
Asexual propagation of Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin can be achieved through various means, including stem cuttings and separation of tubers.
To propagate through stem cuttings, select a healthy stem, cut it into several sections, and plant each section in a pot filled with well-draining soil. Keep the soil moist and warm, and the cuttings should root within a few weeks.
Tubers can be separated during the dormancy period and planted in well-draining soil. The soil should be kept moist and warm until the tubers start to sprout.
In conclusion, Dioscorea preussii Pax subsp. hylophila (Harms) Wilkin can be propagated through both sexual and asexual means, making it relatively easy to propagate.
Disease Management
One common fungal disease that affects Dioscorea preussii Pax subsp. hylophila is anthracnose, which causes leaf spots on the plant. To manage this disease, it is important to regularly remove and destroy infected plant material to prevent the spread of spores. The use of fungicides can also be effective, but it is important to follow application instructions carefully to avoid harm to the plant and the environment.
Another fungal disease that can affect the plant is rust. This disease appears as orange or yellowish-brown spots on the leaves. As with anthracnose, it is important to regularly remove and destroy infected plant material to prevent the spread of spores. Fungicides can also be effective in managing rust, and it is best to use them preventively.
Finally, viruses can also infect Dioscorea preussii Pax subsp. hylophila, causing symptoms such as stunted growth and yellowing leaves. Unfortunately, there are no effective treatments for viral infections, so the best management strategy is to prevent infection by practicing good hygiene, using disease-free plant material, and avoiding mechanical transmission of the virus.
Pest Management
One of the most common pests in Dioscorea preussii Pax subsp. hylophila is the yam beetle. These beetles eat the leaves, stems, and roots of the plant, resulting in reduced growth and yield. To manage yam beetles, it is important to regularly inspect the plants for signs of infestation and to handpick and remove any beetles that are present. The use of insecticidal soap or neem oil can also be effective in controlling yam beetles.
Another pest that can affect the plant is the sweet potato weevil. This pest lays its eggs in the roots of the plant, leading to wilting and reduced yield. To manage sweet potato weevils, it is important to practice crop rotation and to avoid planting Dioscorea preussii Pax subsp. hylophila in areas where sweet potatoes have been grown. Additionally, the use of pheromone traps and insecticides can be effective in controlling sweet potato weevils.
Finally, rodents such as rats and mice can also damage the plant by feeding on the roots. To manage these pests, it is important to eliminate potential nesting sites and to practice good sanitation to prevent the buildup of food sources. The use of traps or baits can also be effective in controlling rodent populations.
