Overview of Phaseolus tunkinensis Lour.
Phaseolus tunkinensis Lour., also known as Tunkin bean or Vietnamese green bean, is a species of legume that belongs to the family Fabaceae. The plant is native to Southeast Asia, specifically in Vietnam, Laos, and Thailand. The plant is primarily grown for its edible beans and traditionally used in various local dishes.
Description of Phaseolus tunkinensis Lour.
The Tunkin bean is a small, herbaceous plant that can grow up to 60 centimeters in height. It has a slender stem with trifoliate leaves, which are dark green and smooth. The flowers are small and white, growing in clusters near the stem. The bean pods are flat and elongated, usually green in color with a slightly curved shape. The seeds inside the pods are small and round, typically light green or yellowish in color.
Uses of Phaseolus tunkinensis Lour.
Phaseolus tunkinensis Lour. is cultivated mainly for its edible beans, which are commonly used in various Vietnamese and Thai dishes. The beans are often cooked in soups, stir-fried dishes, or used as a filling for savory pastries. The Tunkin bean is also a good source of nutrition as it contains a high amount of protein, fiber, vitamins, and minerals. Additionally, the plant is known for its ability to fix nitrogen in the soil, making it an excellent crop for sustainable farming practices.
Cultivation of Phaseolus tunkinensis Lour.
Phaseolus tunkinensis Lour. is mainly grown in tropical and subtropical regions, particularly in Thailand and Vietnam. The plant prefers warm and humid climates, with an average temperature of around 25-30°C. The soil should be well-draining and fertile, with a pH range of 6.0-7.5. The plant is often propagated by seeds, which should be sown during the warm months of the year. The plant requires regular watering and should be provided with adequate support structures to promote vertical growth.
Light Requirements
Phaseolus tunkinensis Lour. requires full sun to partial shade to grow optimally. In areas with high temperatures, the plant benefits from some shade during the hottest time of the day. Lack of adequate sunlight may reduce the yield of the plant.
Temperature Requirements
Phaseolus tunkinensis Lour. grows in warm to hot climates and cannot tolerate frost or freezing temperatures. The optimum temperature range for growth is between 23°C to 28°C. The plant requires warm soil temperatures for seed germination, and seedlings can withstand temperatures of up to 35°C.
Soil Requirements
The plant prefers well-draining soils that are rich in organic matter and have a slightly acidic to neutral pH range of 6.0-7.5. It can also grow in sandy and loamy soils as long as they are well-drained and have sufficient organic matter. The ideal soil temperature for seed germination is between 15°C to 29°C.
Phaseolus tunkinensis Lour. can grow in soils with low fertility, but it benefits from the application of nitrogen and phosphorus. It is important to avoid waterlogged or heavy soils, as this may lead to root rot and stunted growth.
Cultivation methods
The Phaseolus tunkinensis Lour. is a hardy plant that can grow in various types of soils such as loamy, sandy or clay soils. Ensure the soil pH range is between 5.5 and 7.0 to provide the best growing conditions. Plant the seeds in a well-drained soil, and space them 20-30 cm apart. You can sow the seeds directly or transplant seedlings after germination.
Watering needs
Provide plenty of water during the growing season and reduce watering as the plant reaches the dry season to avoid root rot. Water the plant deeply once a week to promote deep root development. In the hot summer season, water the plants more frequently to prevent moisture stress.
Fertilization
Phaseolus tunkinensis Lour. requires fertilization to grow well. The plant needs nitrogen, phosphorous, and potassium nutrients that help in plant growth, root and fruit development. Use well-rotted manure, compost, or fertilizers that have the necessary nutrients. Apply the fertilizers before planting the seeds or transplanting the seedlings to ensure thorough mixing with the soil.
Pruning
Deadhead flowers to encourage bushy, more vigorous growth and a longer flowering period. Pinch out the tips of the plant when it reaches approximately 10 cm to stimulate foliage growth. As the plant matures, prune back any diseased, damaged, or overgrown branches. Remove the lower leaves of the plant to improve air circulation, prevent fungal diseases, and promote flowering.
Propagation of Phaseolus tunkinensis Lour.
Phaseolus tunkinensis Lour. can be propagated through both sexual and asexual methods. The most common propagation methods are seed propagation and vegetative propagation.
Seed Propagation
Seeds of Phaseolus tunkinensis Lour. can be sown directly in the field or in containers. Good quality seeds should be selected for sowing. Seeds should be soaked in warm water for 6-8 hours to promote germination. Sowing should be done in rows, and the distance between rows should be 45-60 cm. The optimal temperature for seed germination is 25-30°C, and germination takes around 7-10 days. Seedlings should be thinned to maintain a distance of 10-15 cm between plants.
Vegetative Propagation
Phaseolus tunkinensis Lour. can also be propagated vegetatively through cuttings. Stem cuttings should be taken from healthy plants. Cuttings should be 15-20 cm long and should have 2-3 nodes. Cuttings should be treated with a rooting hormone and planted in a propagation bed or a container with good quality soil. The optimal temperature for rooting is 25-30°C. Roots develop within 2-3 weeks, and the rooted cuttings can be transplanted to the field after 4-6 weeks.
In conclusion, Phaseolus tunkinensis Lour. can be easily propagated through both seed and vegetative methods. The choice of propagation method depends on the availability of planting materials, time of planting, and intended use of the crop.
Disease and Pest Management for Phaseolus tunkinensis Lour.
Phaseolus tunkinensis Lour., also known as Burmese bean, is a valuable legume crop in subtropical and tropical regions. While it is relatively resistant to common bean diseases, such as anthracnose and common bacterial blight, it is still susceptible to certain pests and diseases that can damage the yield. To ensure optimum plant growth and facilitate a productive crop, disease and pest management practices must be implemented. This article highlights some common diseases and pests that affect Phaseolus tunkinensis Lour., and suggests ways to manage them.
Common Diseases
1. Bean Rust: Bean rust is a fungal disease that appears like orange to reddish-brown lesions on the leaves, pods, and stems of the plant. It can cause severe defoliation and yield loss in severely infected plants. To manage this disease, use rust-resistant plant varieties, maintain suitable crop spacing, and remove severely infected plants or plant parts. Fungicides can also be used.
2. Fusarium Wilt: This fungal disease causes yellowish leaves, stunted growth, and wilting in the infected plant. To manage it, follow crop rotation practices, avoid watering the leaves, and use well-draining soil. Fungicides can also be used.
Common Pests
1. Bean Leaf Beetle: The bean leaf beetle is a common pest that feeds on the leaves and blossoms of the plant, causing extensive defoliation and yield loss. To manage it, use seed treatments, install pheromone traps, or use insecticides.
2. Aphids: Aphids suck the sap from the plant's leaves, causing them to curl and distort. They also transmit viral diseases, which can affect the yield. To manage them, use insecticidal soap, neem oil, or plant resistant varieties.
Conclusion
Proper disease and pest management practices can help to minimize the damage caused by pests and diseases, and ensure a good yield. Regular scouting and monitoring of the crop, combined with the adoption of appropriate pest and disease control measures, can help to prevent significant losses. Potential disease and pest management methods include the use of resistant plant varieties, crop rotation, good irrigation practices, and the application of appropriate pesticides.
