The Sweet Potato (Ipomoea batatas) is an herbaceous plant with tuberous, edible roots, and is of significant agricultural and nutritional importance, cultivated in various tropical and subtropical regions of the world. The scientific name of the Sweet Potato, Ipomoea batatas, has etymological roots that reflect distinctive characteristics of the plant. The genus Ipomoea is derived from the Greek “ips” (worm) and “homoios” (similar), alluding to the climbing growth habit of the species in this genus, whose stems resemble worms or snakes. The specific epithet batatas comes from the indigenous word “batata” or “batatas“, used by the natives of the Americas to name this edible root.
The Ipomoea batatas is native to the tropical regions of the Americas, from the region now known as Ecuador. Archaeological evidence indicates that its domestication occurred at least 5,000 years ago in Central America, with the oldest remains dating to around 8000 B.C. in Peru. The plant adapts to a variety of habitats, preferring well-drained soils and warm climates. Its lifecycle is perennial in its native regions; however, in many cultivation areas, it is managed as an annual, with harvests scheduled according to local weather conditions.
The dispersion of the Sweet Potato around the world occurred significantly during the 15th and 16th centuries. Spanish and Portuguese explorers introduced the plant in Europe, Africa, and Asia. In China, the Sweet Potato was introduced around 1594, becoming a vital crop for food security. In Japan, its introduction occurred in the early 17th century, playing a crucial role in preventing famine during insufficient or pest and disaster ravaged rice harvests. Today, it is one of the growing food crops in Africa, playing a significant role in combating malnutrition.
Sweet Potato occupies a prominent position among various food crops, being a vital source of low glycemic index carbohydrates, fibers, vitamins, and minerals.
Rich in vitamin A, especially in the orange-fleshed varieties, sweet potatoes significantly contribute to health. Additionally, they provide vitamin C, potassium, and iron, essential nutrients for various functions. Their culinary versatility allows for the consumption of the roots in baked, boiled, fried, or pureed forms. The leaves and shoots are also edible after brief cooking, offering an additional source of nutrients. In some cultures, sweet potatoes are used in the production of products like flours, sweets, and fermented beverages.
An detail that most people are unaware of about sweet potatoes is their condition as a naturally transgenic plant. Research has revealed that their genome contains large sequences of DNA from bacteria of the genus Agrobacterium, with genes actively expressed by the plant.This phenomenon suggests that sweet potatoes underwent a natural genetic modification process throughout their evolution, differentiating them from other crops.
Sweet potatoes develop a fibrous and extensive root system, with adventitious roots originating from the nodes of the stems. Some of these roots specialize in nutrient storage, forming the edible tubers we know. These tubers vary in shape (elongated, spindle-shaped, rounded), size, and color of the skin and flesh, depending on the cultivar. It is a herbaceous plant with prostrate or semi-erect growth, tending to form dense vegetative mats. Under favorable conditions, it can cover large areas, suppressing the growth of competing plants.
Their stems are slender, flexible, and can reach significant lengths (up to about 13 feet), often rooting at the nodes when in contact with the soil. They exhibit colors ranging from green to purple, depending on the variety. Secondary branches emerge from the nodes, contributing to the horizontal expansion of the plant. The leaves are alternate, simple, and show considerable variability among cultivars. They can be entire, heart-shaped, lanceolate, or deeply lobed.
The color of the leaves varies from light green to dark green, occasionally with purplish and bronzed tones.
This great variation in foliage colors has motivated the development of ornamental cultivars of the plant, which are quite popular. The leaves have long petioles and are responsible for photosynthesis, and they are also edible after proper preparation.
The blooming of the Sweet Potato is not uniform and can vary according to the cultivar and environmental conditions. In some tropical regions, flowering occurs during vegetative development, while in others it is rare or nonexistent. However, they are important for the development of new cultivars and genetic selection.
The inflorescences are of the cymose type, with solitary flowers or grouped in small clusters. The flowers are hermaphroditic, with a gamopetalous corolla shaped like a funnel, typical of the Convolvulaceae family, ranging in color from pink to lilac, with a darker center. The calyx is formed by five free sepals, and the stamens are included, inserted at the base of the corolla. Pollination is predominantly cross and carried out by insects, especially bees.
However, due to the low frequency of flowering in many cultivars, sexual reproduction is less common, with vegetative propagation through slips or tubers being the preferred method of multiplication. When fruiting occurs, the fruits are globular, dehiscent capsules, usually containing 1 to 4 seeds. The seeds are small, dark-colored, and have a hard testa, a characteristic that contributes to dormancy and makes natural germination difficult.
Sweet Potato features several cultivars adapted to different regions and consumption preferences. Below are some of the main cultivars grown worldwide:
- Beauregard
- Highlight regions: United States (especially the South), Latin America, Australia, and European countries.
- Characteristics: Developed in Louisiana, this cultivar is known for its copper-colored skin and vibrant orange flesh.
It is famous for its high yield, disease resistance, and sweet flavor. It is widely used in preparations such as purees, baked dishes, fries, and chips.
- Covington
- Key Regions: United States, especially in North Carolina.
- Characteristics: Introduced by North Carolina State University, it features pink skin and orange flesh. It is valued for its uniform shape, sweet flavor, and firm texture after cooking. Ideal for baked dishes, boiled preparations, and desserts.
- Evangeline
- Key Regions: United States.
- Characteristics: Similar to Beauregard in appearance, but with a higher sugar content, resulting in a sweeter flavor. It has moderate disease resistance and is prized for its culinary quality. Frequently used in desserts, breads, and sweet potato cakes.
- Murasaki-29
- Key Regions: United States and Japan.
- Characteristics: A cultivar with purple skin and white flesh, known for its dry texture and sweet flavor with nutty notes. Popular in Asian cuisine and among consumers who prefer a less moist sweet potato. Ideal for baked, boiled, and crispy fried dishes.
- Okinawan
- Key Regions: Japan, Hawaii, and other Pacific regions.
- Characteristics: It has light skin and intense purple flesh. Rich in antioxidants, especially anthocyanins, it is valued both for its health benefits and for its sweet flavor and creamy texture. Widely used in traditional desserts, as well as in purees and mochi.
- Brazlândia Series
- Key Regions: Brazil.
- Characteristics: A set of cultivars developed by Embrapa, including Brazlândia Roxa, Brazlândia Branca, and Brazlândia Rosada. They are notable for their adaptation to Brazilian conditions, productivity, and disease resistance. Used for consumption raw, baked, boiled, or as an ingredient in regional dishes.
- BRS Amélia
- Key Regions: Brazil.
- Characteristics: A cultivar developed by Embrapa, featuring skin and flesh of an orange hue. It stands out for its high beta-carotene content, sweet flavor, and good market acceptance.
Commonly used in baby food, sweets, and functional baked goods.
- Coquinho
- Key regions: Brazil.
- Characteristics: Known for its small, rounded roots with purple skin and white flesh. It has a sweet flavor and is popular in regional culinary preparations. Often used roasted whole, in preserves and compotes.
- Princesa
- Key regions: Brazil.
- Characteristics: A cultivar with pink skin and cream flesh, known for its productivity and mild flavor. Adapted to various growing conditions in the country. Ideal for home use and traditional cooking, including soups and breads.
- Orange-fleshed Sweet Potato (OFSP)
- Key regions: Sub-Saharan Africa, Asia, and Latin America.
- Characteristics: A group of cultivars with orange flesh, rich in beta-carotene. Promoted in food security programs and combating vitamin A deficiency, particularly in developing countries. Used in porridge, cakes, purees, and school feeding programs.
- Bellevue
- Key regions: Europe and Australia.
- Characteristics: A cultivar with orange skin and intense orange flesh. Known for its uniform shape, sweet taste, and soft texture after cooking. Commonly used in baked dishes, stir-fries, and as a side dish for meats.
- Owairaka Red
- Key regions: New Zealand.
- Characteristics: Features red skin and cream flesh. Valued for its firm texture and sweet flavor, it’s one of the main cultivars grown in the country. Frequently used in grilling, baking, and as a filling for traditional pastries.
- Boniato
- Key regions: Caribbean, Central America, and parts of South America.
- Characteristics: Also known as Cuban sweet potato, it has clear skin and white flesh. It presents a dry texture and mild flavor, widely used in Caribbean cooking. Popular in savory dishes, stews, and fried foods.
- Sushu-2
- Key regions: China.
- Characteristics: A cultivar developed for temperate climate regions, it features high productivity and disease resistance.
Used for both fresh consumption and industrial processing. Ideal for starches, noodles, snacks, and flours.
- Kabode
- Key Regions: East Africa, especially Uganda.
- Characteristics: This cultivar has orange flesh rich in beta-carotene. Promoted in nutrition programs to combat vitamin A deficiency, it shows good adaptation to local conditions and resistance to pests. Consumed mainly in porridges, cakes, purees, and simple fries.
These cultivars reflect just a small portion of the genetic diversity and adaptability of Sweet Potato to various conditions and cultural preferences around the world. When selecting the best cultivar for your region, research the main cultivars selected for your climate, soil type, and flavor preference. Thus, the chances of achieving higher productivity and better alignment with your preference will be improved. Sweet Potato is highly valued in home gardens due to its adaptability and ease of cultivation. It can be integrated into functional and biodiverse gardens, contributing to more resilient and sustainable green spaces.
Incorporating Sweet Potato into gardens allows for productive and aesthetically pleasing landscapes. Its vigorous growth, and ground-cover and climbing habit make it suitable for use as ground cover, reducing erosion and suppressing weeds. Growing in hanging baskets or pots is also compelling, offering beautiful and practical solutions for small urban gardens. Combine it with foliage of different colors, as well as delicate and colorful flowers, such as petunias or tagetes. Integrating Sweet Potato into community or school gardens can serve as an educational tool, teaching sustainable agricultural practices and promoting awareness of healthy eating. This approach not only improves nutrition but also strengthens community bonds and values traditional knowledge.
Sweet Potato thrives in tropical and subtropical climates, preferring mild temperatures ranging between 57°F and 79°F (14°C and 26°C). In areas where soil temperature can drop below 55°F (12.5°C), the roots risk being damaged and losing quality. The plant is sensitive to extreme temperatures; above 86°F (30°C), its growth may be impaired. However, there are cultivars suitable for temperate climates, where they are grown as annuals, and others suited for warmer climates.
Sweet Potato requires high sunlight availability for proper development. The intensity and duration of sun exposure directly influence the formation and accumulation of sugars in the roots, affecting both the quality and yield of the crop. It can be grown under partial shade, especially for ornamental and landscaping purposes, but its roots will not be as sweet as those grown under full sun.
Regarding soil, Sweet Potato adapts to a variety of types, but prefers deep, well-drained soils with good organic matter availability. Clayey and compacted soils are not ideal, as they may hinder the growth of tuberous roots and increase the incidence of diseases. The ideal pH range for cultivation is between 5.5 and 6.5.
Moreover, it is important that the soil has good moisture retention capacity without being prone to waterlogging, which can cause root rot. Soil preparation is crucial for the development of long, robust roots. A light, airy soil is essential for establishing Sweet Potato in the garden.
Irrigation of Sweet Potato should be managed to keep the soil adequately moist, especially during the initial stages of growth and tuberous root formation. Although the plant tolerates dry periods, lack of water can significantly reduce productivity.
It is recommended to irrigate regularly, avoiding both lack and excess of water, which can lead to waterlogging and favor the development of root diseases such as rot. Fertilization should be based on a prior soil analysis and according to the requirements of the crop, which are already well established. Do not allow a deficiency of phosphorus, potassium, and nitrogen for the full development of the Sweet Potato. In organic cultivation, these nutrients can be provided using well-rotted manure, rock dust, bone meal, and ash (salt-free). Do not forget to apply mulch to the soil to prevent nutrient loss and maintain moisture and aeration.
In traditional cultivation, nitrogen should be applied cautiously, as its excess can promote excessive growth of the aerial part at the expense of the formation of tuberous roots. If the plants show excessive vigor, nitrogen application can be dispensed with. Cultural practices include techniques such as weeding for weed control, hilling to encourage root development, and constant monitoring for early detection of pests and diseases. Crop rotation and intercropping with other plants is an effective strategy to reduce the incidence of pathogens in the soil and improve its structure and fertility.
The Sweet Potato is subject to the attack of various pests and diseases that can compromise the productivity and quality of the roots. Among the pests, mites stand out, whose population growth is favored by warm temperatures and dry climate. The control of these pests should be done through constant monitoring and the adoption of integrated measures, such as the use of resistant varieties, biological control, and proper management of the cultivation environment. Among the diseases, root rot is one of the most harmful, often associated with waterlogged or poorly drained soils. Choosing areas with good drainage, crop rotation, and the use of healthy planting material are important preventive measures. In humid terrains, the use of raised beds favors its development. Additionally, the elimination of infected plants and the control of insect vectors contribute to the reduction of disease spread.
Sweet Potato propagation is predominantly carried out through vine cuttings, owing to the efficiency and uniformity this method provides. The vine cuttings used for planting should be selected from healthy and vigorous plants, preferably taken from young fields (up to 90 days). The use of cuttings from older crops (over 90 days) is not recommended, as it may result in lower productivity and a higher incidence of diseases.
The planting cycle of Sweet Potatoes, from the vine cuttings to the root harvest, begins with planting the cuttings in well-prepared furrows or ridges, with spacing generally of 2.6 to 3.9 feet (0.8 to 1.2 meters) between rows and 0.82 to 1.3 feet (0.25 to 0.4 meters) between plants. In subtropical to temperate climates, the best planting time is in the spring, when temperatures are mild. In tropical regions, it is ideal to plant at the beginning of the rainy season, although Sweet Potato can be planted throughout the year in regions with irrigation or well-distributed rainfall. After planting, the cuttings emit adventitious roots that fix into the soil and develop the aerial part in about 30 days.
From the vegetative phase, which can last from 45 to 60 days, the formation of the tuberous roots begins, a process influenced by factors such as light, nutrition, and soil moisture. The complete cycle of the crop varies from 90 to 150 days, depending on the cultivar, climatic conditions, and management adopted. Harvest is carried out when the roots reach the appropriate size and color for consumption, and must be done carefully to avoid injuries that compromise the quality and preservation of the Sweet Potatoes.
Propagation by seeds is rare and generally limited to genetic improvement programs, aiming at obtaining new cultivars. This method is not used commercially due to the heterogeneity of the resulting plants and the longer time required for tuberous root development.
Although it is possible to propagate Sweet Potatoes through small roots or pieces of roots, this practice is not recommended for commercial purposes. This is because it can reduce productivity, increase the crop cycle, produce smaller and lower quality potatoes, and facilitate the transmission of diseases and pests. However, the use of roots can be useful in forming nurseries for the production of quality seedlings or vine cuttings.
