Overview: Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet & Harlan
Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet & Harlan is a plant species commonly known as "sweet sorghum" or "sugar cane sorghum," which belongs to the family Poaceae. It is a type of tropical cereal crop that is mainly cultivated for its edible grain and syrup production. The plant is characterized by its tall stature, long, broad leaves, and cylindrical inflorescence or panicle that carries numerous flowers at the top.
Origin and Distribution
The origin of Sorghum bicolor is believed to be Africa, particularly in the northeastern region. However, it is now widely cultivated around the world, including Asia, Australia, Europe, and America. The plant grows best in warm, subtropical to tropical areas with temperatures ranging from 20 to 35°C and an annual rainfall of at least 400mm.
Common Names
Sweet sorghum or sugar cane sorghum are the two common names used to refer to Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet & Harlan. However, other local and regional names also exist, including sorgo, durra, milo, or shallu in India, guinea corn in West Africa, and kaoliang in China.
Uses
Sorghum bicolor is a versatile crop that has various uses in different parts of the world. In Africa, the grains are commonly milled to make flour used in porridge, bread-making, and other food preparations. In India and China, the grains are also used for making alcoholic beverages such as beer and liquor. The stalks of the plant are crushed to extract sugary juice, which is then processed to obtain syrup or molasses primarily used as a sweetener. Recently, the juice is also used to produce biofuels, animal feed, and paper.
Appearance
Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet & Harlan is a tall, upright plant that can grow up to 5 meters in height. The leaves are broad, up to 1.5 cm wide, and can grow up to 90 cm long. The inflorescence is a panicle that can range from 10 to 75 cm in length, with numerous flowers forming on its branches. The seeds of the plant are small, ovoid, and can range from yellowish to reddish-brown in color.
hereLight Requirements
Sorghum bicolor ssp. drummondii requires full sunlight for optimal growth. It thrives in areas with at least six hours of direct sunlight per day. Shaded areas can lead to stunted growth and decreased yields.
Temperature Requirements
Sorghum bicolor ssp. drummondii is a warm-season crop, preferring temperatures between 25°C to 35°C for optimal growth. Seeds require a minimum soil temperature of 18°C for germination. Temperatures below 15°C can cause the plant to become dormant. Frost can be detrimental to this species, as it is not frost-tolerant. Therefore, it is best to plant after the last frost date in the growing season to avoid any damage.
Soil Requirements
The ideal soil for Sorghum bicolor ssp. drummondii is well-drained, fertile, with a pH range from 5.5 to 7.5. It requires moderate moisture to thrive, but it can tolerate drought conditions. The plant has adapted to a variety of soil types, including sandy, loamy, and clay soils. However, heavy soils with poor drainage affect root development and can lead to stunted growth. Therefore, it is crucial to choose a site with good soil conditions for this crop.
Cultivation Methods
Sorghum bicolor ssp. drummondii is a warm-season, annual grass that is typically cultivated for grain production in hot and arid regions. It grows best in well-drained soil with a pH range of 5.5 to 7.5 and requires a moderate amount of sunlight. Prepare the soil by plowing it well and incorporating manure or compost, then sow the seeds directly into the soil at a depth of 1-2 inches. Planting should be done after the last frost, and it is important to keep the soil moist until the seedlings emerge.
Watering Needs
Sorghum bicolor ssp. drummondii requires regular watering for optimal growth, especially during the initial stages of development. Water the plants deeply once or twice a week, depending on the climate, to promote deep root development. After the plants reach maturity, reduce the frequency of watering to prevent over-watering, which can lead to nutrient leaching and root rot. However, ensure that the plants do not experience water stress by checking for signs such as wilting or yellowing of leaves.
Fertilization
Sorghum bicolor ssp. drummondii requires regular fertilization to promote healthy growth and higher yields. Apply a balanced, nitrogen-rich fertilizer before planting and provide subsequent applications at intervals of 3-4 weeks during the growing season. It is important to follow recommended fertilizer application rates to prevent fertilizer burn or nutrient toxicity. Additionally, consider using organic fertilizers such as bone meal or compost since they not only provide essential nutrients but also improve soil fertility and structure.
Pruning
Sorghum bicolor ssp. drummondii does not require pruning as it grows in a bushy, compact manner. However, removing diseased or dead stems can help promote healthier growth and prevent the spread of diseases. It is essential to sanitize pruning tools before and after use to prevent cross-contamination. Additionally, remove any weeds growing around the plants to reduce competition for essential nutrients and prevent the spread of pests and diseases.
Propagation of Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet & Harlan
Sorghum bicolor (L.) Moench ssp. drummondii, also known as Sudan grass, is a warm-season annual grass characterized by its rapid growth and ability to withstand drought and high temperatures. It is an important forage crop for livestock and can also be used for erosion control and as a biofuel source. Sorghum bicolor (L.) Moench ssp. drummondii can be propagated through several methods including seed propagation, vegetative propagation, and tissue culture.
Seed Propagation
Seed propagation is the most common method of propagating Sorghum bicolor (L.) Moench ssp. drummondii. The seed should be planted in a well-drained soil that is rich in organic matter. Planting should be done when the soil temperature is at least 60°F (15°C) and the danger of frost has passed. The seeds should be planted at a depth of 1 to 2 inches (2.5 to 5 cm) and spaced 6 to 12 inches (15 to 30 cm) apart. The seeds will germinate within 5 to 10 days.
Vegetative Propagation
Vegetative propagation is another method of propagating Sorghum bicolor (L.) Moench ssp. drummondii. This method involves using stem cuttings from mature plants to propagate new plants. The stem cuttings should be taken from the middle portion of the stem and should be at least 6 inches (15 cm) long. The cuttings should be planted in a well-drained soil and kept moist until they develop roots. Vegetative propagation is usually done in early spring or late fall when the soil temperature is between 60°F (15°C) and 70°F (21°C).
Tissue Culture
Tissue culture is a more advanced method of propagating Sorghum bicolor (L.) Moench ssp. drummondii. This method involves taking small pieces of the plant tissue and growing them in a nutrient-rich growth medium under controlled environmental conditions. Tissue culture is typically used to produce large numbers of uniform plants that are disease-free and genetically identical. This method is commonly used for research purposes, but it is also used for commercial production of Sorghum bicolor (L.) Moench ssp. drummondii.
Disease Management
Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet & Harlan is susceptible to a number of diseases that could cause significant damage to the plants. The following are some of the common diseases that can affect sorghum:
- Anthracnose: This disease is caused by the fungus Colletotrichum graminicola and is characterized by the appearance of small and dark spots on leaves, stems, and panicles. The disease can lead to premature death of plants, grain discoloration, reduced yields, and poor grain quality. Anthracnose can be prevented through the use of disease-resistant cultivars, crop rotation, and the application of fungicides.
- Charcoal rot: This disease is caused by the fungus Macrophomina phaseolina and can affect sorghum plants at any stage of development. The disease is characterized by the appearance of blackened stems and roots, wilting, and premature plant death. Crop rotation, seed treatment, and soil solarization are some of the effective management strategies for charcoal rot.
- Downy mildew: This disease is caused by the fungus Peronosclerospora sorghi and is characterized by the appearance of yellowish patches on leaves, which later turn brown and dry. Downy mildew can cause significant yield losses, especially in humid conditions. Planting disease-resistant cultivars, practicing good sanitation, and applying fungicides can help prevent this disease.
Pest Management
In addition to diseases, Sorghum bicolor (L.) Moench ssp. drummondii (Nees ex Steud.) de Wet & Harlan is also prone to pest attacks that can reduce yields and cause significant economic harm. The following are some of the common pests that can affect sorghum:
- Sorghum midge: This pest is characterized by its tiny size and straw-colored appearance. The sorghum midge attacks sorghum flowers and can cause panicles to drop prematurely, reducing yields. Planting early-maturing cultivars, applying insecticides, and practicing good field hygiene are effective management strategies for sorghum midge.
- Stem borer: This pest is a major problem in many sorghum-growing regions, especially in Africa. The larvae of the stem borer feed on the inner stem tissues, causing plants to wilt and die. The use of resistant varieties, the application of insecticides, and the practice of crop rotation can help prevent stem borer attacks.
- Aphids: These small insects can feed on sorghum leaves, causing them to turn yellow and wilt. Aphids can also transmit virus diseases, leading to reduced yields. The use of insecticidal soap, neem oil, and the planting of resistant cultivars are effective management strategies for aphids.
