Overview
Vigna unguiculata (L.) Walp. subsp. protracta auct. is a subspecies of Vigna unguiculata, commonly known as cowpea, southern pea, or black-eyed pea. It belongs to the legume family Fabaceae and is widely cultivated in Africa, Asia, the Americas, and the Caribbean for its edible seeds and pods.
Origin
The exact origin of cowpea is uncertain, but it is believed to have originated in Africa around 5000 years ago. From there, it spread to other parts of the world through trade and migration. Today, it is widely cultivated in tropical and subtropical regions of the world.
Common Names
Cowpea is known by many common names in different parts of the world. In Africa, it is called niébé, feuille mala, or frijol carita. In the Caribbean, it is known as black-eyed pea or pigeon pea. In the southern United States, it is commonly called southern pea or cowpea.
General Appearance
Cowpea is an annual plant that can reach up to 2 meters in height. It has a deep taproot system and produces erect stems that are woody at the base. The leaves are pinnately compound, with 3-4 leaflets, and are alternate along the stem. The flowers are small, white, pink, or purple and can appear singly or in groups. The pods are long and narrow, up to 30 cm in length, and contain 10-20 seeds. The seeds are kidney-shaped, cream, brown, or black in color, and have a characteristic black eye.
Uses
Cowpea is primarily grown for its edible seeds and pods. The seeds can be eaten fresh or dried and are used in soups, stews, and curries. They are also a good source of protein, dietary fiber, and essential micronutrients, making them an important food crop for people in developing countries. The leaves and young shoots of cowpea can be used as a vegetable and are often cooked like spinach or added to stews and soups. In addition, cowpea is a popular cover crop as it can fix nitrogen in the soil, improve soil health, and prevent erosion.
Light Requirements
Vigna unguiculata (L.) Walp. subsp. protracta auct. grows best in full sun. It requires a minimum of 6 hours of direct sunlight per day to thrive. The plant will tolerate some shade but will not produce as many flowers and pods in low light levels. Therefore, it is recommended to plant the crop in a location where it can receive plenty of sunlight.
Temperature Requirements
The ideal temperature range for growing Vigna unguiculata (L.) Walp. subsp. protracta auct. is between 25°C to 35°C. The minimum temperature requirement for the germination of seeds is 15°C, while the maximum temperature limit is 45°C. The plant is sensitive to frost and cannot tolerate low temperatures below 10°C. Therefore, it is recommended to grow the crop in a warm and humid climate.
Soil Requirements
Vigna unguiculata (L.) Walp. subsp. protracta auct. can grow in various soil types including sandy, loamy, and clay soils. However, it grows best in well-drained loamy soils with a pH ranging between 6.0 to 7.5. The soil should be rich in organic matter, and well-aerated to ensure optimum growth. It is advisable to avoid poorly drained soils as they can lead to root rot and other diseases in the plant.
Cultivation methods
Vigna unguiculata (L.) Walp. subsp. protracta auct. can be cultivated successfully in tropical and subtropical regions. It can be grown in a variety of soils, although well-draining soils are preferred. The plant requires a warm, sunny location to thrive and should be protected from strong winds. It is best to plant the seeds directly into the soil, as they do not transplant well. The optimal planting time is at the start of the rainy season.
Watering needs
Vigna unguiculata (L.) Walp. subsp. protracta auct. requires regular watering throughout the growing season. The soil should be kept consistently moist, but not waterlogged. During periods of drought, it is important to increase the frequency of watering to prevent dehydration. It is recommended to use drip irrigation or a soaker hose to avoid wetting the foliage and causing fungal diseases.
Fertilization
The plant requires regular fertilization to maintain optimal growth and production. A balanced fertilizer with equal amounts of nitrogen, phosphorus, and potassium should be applied every four to six weeks. Compost or well-rotted manure can also be used to supplement the soil with nutrients. It is important not to over-fertilize, as this can lead to excessive vegetative growth at the expense of fruit production.
Pruning
Pruning can be used to promote a more compact plant and increase fruit production. Pinching off the growing tip of the main stem when the plant is 20-25 cm tall will cause it to branch out and produce more blooms and fruit. For best results, remove any damaged or diseased branches regularly. It is important not to prune too aggressively, as this can reduce the yield of the plant.
Propagation Methods
There are several propagation methods for Vigna unguiculata subsp. protracta auct. including seed propagation, vegetative propagation, and tissue culture.
Seed Propagation
Seed propagation is the most common method for propagating Vigna unguiculata subsp. protracta auct. Seeds should be planted in well-draining soil with a neutral pH and ample sunlight. The seeds should be kept moist but not waterlogged to prevent rotting. Germination usually occurs within 7-10 days.
Vegetative Propagation
Vigna unguiculata subsp. protracta auct. can also be propagated vegetatively through stem cuttings. Cuttings should be taken from the plant and placed in moist soil. The soil should be kept moist and in a warm area until new growth appears.
Tissue Culture
Tissue culture is another propagation method for Vigna unguiculata subsp. protracta auct. Tissue culture involves taking a small piece of the plant and growing it in a sterile medium. This process is highly controlled and can be used to produce large numbers of genetically identical plants.
Disease and Pest Management for Vigna unguiculata (L.) Walp. subsp. protracta auct.
Vigna unguiculata (L.) Walp. subsp. protracta auct., commonly known as cowpea or southern pea, is a hardy legume that is commonly grown in warm regions. However, like all plants, it is susceptible to a range of diseases and pests. Proper management of these issues is essential for healthy plant growth and a bountiful harvest.
Common Diseases
Cowpea is prone to various fungal and bacterial diseases that can cause significant damage to the plant. One of the most common diseases is anthracnose, caused by the fungus Colletotrichum lindemuthianum. Symptoms of this disease include dark, sunken spots on the leaves, stems, and pods. To manage anthracnose, use disease-resistant varieties, practice crop rotation, and apply fungicides as necessary.
Another common fungal disease that affects cowpea is rust, caused by the fungus Uromyces appendiculatus. Rust appears as small, reddish-brown pustules on the leaves, which can lead to severe defoliation and reduced yields. To manage rust, plant disease-resistant varieties, remove infected plant debris immediately, and apply fungicides as necessary.
Common Pests
In addition to diseases, cowpea is also vulnerable to various insect pests, including aphids, stink bugs, and thrips. Aphids and thrips feed on plant sap, causing yellowing and stunted growth, while stink bugs feed on the developing pods, causing discolored, malformed, or shriveled peas.
To manage these pests, regular monitoring of the plants is essential. Early detection can help prevent severe infestations. Cultivate healthy plants by providing adequate water and nutrients, and use insecticides as needed. Alternatively, consider using organic methods such as row covers or insecticidal soap to control pests.
Cultural Practices
In addition to chemical management, cultural practices can also help prevent and manage diseases and pests in cowpea. Crop rotation with non-host plants is one such practice, as it helps prevent soil-borne diseases from building up in the soil. Avoid planting cowpea in the same location consecutively.
Another cultural practice is planting disease-resistant varieties and ensuring that plants are well-spaced and not overcrowded, as this can lead to increased disease and insect pressure. Remove any infested plant material immediately to prevent the spread of disease and pests.
Finally, maintaining proper soil pH and fertility levels and practicing good irrigation techniques can promote healthy plant growth, making them less susceptible to diseases and pests.
