Overview: Brassica Rapa L. var. Rapa
Brassica rapa L. var. rapa, commonly known as turnip, is a root vegetable that belongs to the Brassicaceae family. It is mainly grown for its white, bulbous, edible root and its green, leafy tops.
Origin
The origin of Brassica rapa can be traced back to the Mediterranean region, with turnip cultivation dating back to ancient Greece and Rome. However, the exact origin of turnips is still unknown.
Common Names
Turnips are known by several common names around the world, including neeps (Scotland), swedes (England), and rutabaga (North America).
General Appearance
Turnip plants consist of a rosette of leaves ranging from green to blue-green in color. The leaves are lobed and have a slightly hairy texture. The root of the turnip is bulbous or round-shaped, ranging in size from small (golf ball size) to large (softball size). The skin of the root varies from white to creamy yellow or light purple, while the flesh is white. The plant produces a flower stem covered in tiny yellow flowers.
Uses
The root of the turnip is edible and commonly used in cooking. It can be roasted, boiled, mashed, or used in stews and soups. The greens of the turnip are also edible and can be cooked just like other leafy greens. In addition to its culinary uses, turnip has been used in traditional medicine to treat several ailments such as coughs and colds, arthritis, and indigestion.
Light Requirements
Brassica rapa L. var. rapa, also known as turnip, requires full sun to grow. Ensure that the plant receives at least 6-8 hours of direct sunlight daily. Low levels of light may result in poor growth and elongated stems.
Temperature Requirements
The ideal temperature range for growing turnips is between 50-75°F (10-24°C) during the day and 40-55°F (4-12°C) at night. The plant can tolerate light frosts but experiences stunted growth in temperatures above 80°F (27°C).
Soil Requirements
Turnips grow well in well-drained fertile soil with a pH range of 5.5-6.8. The soil should be rich in organic matter and have good water-holding capacity. Soil compaction can hinder root penetration and development.
Avoid planting turnips in areas with heavy clay soils that retain more water than necessary. Poorly-drained soil leads to waterlogged conditions that encourage root rot and slow plant growth.
It's recommended to perform a soil test to analyze the nutrient levels and pH balance before planting the turnips. The ideal soil preparation involves mixing organic matter like compost or well-rotted manure into the top 6-8 inches of soil.
Cultivation Methods
Brassica rapa L. var. rapa, commonly known as turnips, grows well in moist and cool climates. It thrives in well-drained soil with a pH level of 6.0-7.5. Select a sunny or partially shaded location with good air circulation for planting turnips. Turnip seeds can be directly sowed in the soil during the early spring or late summer months. Seeds can be sowed at a depth of 1/2 inch and about 2 inches apart from each other.
Watering Needs
Turnip plants require adequate moisture for growth and development. Water the plants regularly to keep the soil moist but avoid overwatering, which can cause root rot. Inadequate water supply can cause the roots to become woody and affect the taste. Mulching around the plants can help retain soil moisture and prevent the growth of weeds.
Fertilization
Turnip plants require a balanced and nutrient-rich soil for optimal growth. Incorporate well-rotted compost or manure into the soil before planting the seeds. Additionally, apply a balanced fertilizer, such as 10-10-10, after four weeks of planting the seeds. Repeat the fertilizer application every four weeks until the plants mature. Over-fertilization can cause lush green foliage, but the turnips may not develop a good taste.
Pruning
Unlike other plants, turnip plants do not require extensive pruning. However, thinning the plants is necessary to ensure adequate spacing and better-sized turnips. Thin the plants when they are about 2-3 inches tall, leaving about 3-4 inches of space between each plant. Additionally, remove yellow and damaged leaves from the plant's base, as they can attract pests and disease-causing organisms.
Propagation of Brassica rapa L. var. rapa
Brassica rapa L. var. rapa, also known as the turnip, is a biennial or annual plant that is widely cultivated for its edible root vegetable. To propagate this plant, growers can use different methods, such as:
Seed Propagation
The most common method of propagating Brassica rapa L. var. rapa is through seeds. Since the turnips are biennials, the plant will flower and develop seed pods in its second year of growth. The seeds can be collected from the dried pods, stored, and used for the next season's planting. Seed propagation is the preferred method for commercial growers because it yields a large number of plants that are genetically identical.
Vegetative Propagation
Brassica rapa L. var. rapa can also be propagated vegetatively, although this method is not as common. It involves dividing the root of the plant into sections and planting them in new soil. This process is known as root division and can be done during the fall season. Vegetative propagation can be useful when growers want to maintain specific characteristics of a plant, but it is not generally preferred due to the lower yield and requirement for delicate handling.
Cutting Propagation
A third method of propagating Brassica rapa L. var. rapa is through stem cuttings. This technique involves taking a section of the stem from a mature plant and growing it in a rooting medium to form new roots. Cutting propagation is not commonly used for turnips due to the low success rate and time-consuming process.
Overall, the most common and efficient method for the propagation of Brassica rapa L. var. rapa is seed propagation. This method yields a large number of plants that are genetically identical and easy to grow.
Disease and Pest Management for Brassica rapa L. var. rapa
Brassica rapa L. var. rapa, commonly known as turnip, is a cool-season crop that is typically grown for its roots, but the leaves can also be eaten as a vegetable. While this plant is relatively easy to grow, it is susceptible to a range of diseases and pests that can significantly reduce both yield and quality. Therefore, effective disease and pest management is essential for growing healthy and productive turnips.
Common Diseases
Several diseases can affect turnips, including:
- Clubroot: This is a soil-borne disease caused by the fungus Plasmodiophora brassicae, which infects the roots and causes them to become swollen and misshapen. Clubroot can severely reduce yield and can persist in the soil for up to 20 years.
- Black rot: This is a bacterial disease caused by Xanthomonas campestris, which affects the leaves, stems, and bulbs. The affected tissue turns yellow and dies, and the entire plant can wilt and die.
- Downy mildew: This is a fungal disease caused by Peronospora parasitica, which affects the leaves and causes yellowing and a downy growth on the undersides of the leaves.
To manage these diseases, it is essential to practice good crop rotation, keeping turnips on a 3-4 year rotation cycle. Also, selecting disease-resistant varieties and planting them on well-drained soils is recommended. In cases where disease infestation is severe, an application of fungicides or bactericides may be necessary.
Common Pests
Tuminps can also be affected by several pests, including:
- Root maggots: These are the larvae of the fly Delia radicum, which feed on the roots and tunnel into the bulbs. Severely affected plants show stunted growth and can die before maturing.
- Cabbage aphids: These are small, soft-bodied insects that suck sap from the leaves and stems, causing them to yellow and wilt. Infested plants can become stunted and may not mature properly.
- Cutworms: These are the larvae of several species of moths that cut young seedlings at the base, causing them to wilt and die. Cutworms feed at night and hide in soil cracks or debris during the day.
To manage these pests, it is recommended to practice good cultural practices, such as regular weeding and maintaining clean fields. Avoid planting turnips near fields that have suffered from pest infestations. Also, applying insecticides or biological controls such as parasitic wasps, nematodes, or fungi may be necessary to control severe infestations.
Overall, managing diseases and pests requires a combination of preventive and curative measures. Observing the crop regularly and taking appropriate action when necessary can help control most plant problems.
