SORGHUM: CHARACTERISTICS, HABITAT, NUTRITION, USES, SPECIES - BIOLOGY - 2025

The sorghum or Sorghum spp., Is a genus of Poaceae (Gramineae) comprises about 31 species. Some of those it comprises are located within the five most consumed cereals worldwide.

The plants of this genus are rhizomatous or stoloniferous, with a well-developed root system that allows them to store reserves, and a greater ability to penetrate the soil to be able to resist dry weather or water stress for longer.

Sorghum cultivation. Source: pixabay.com

It has alternate, linear or lanceolate, narrow or broad leaves. The flowers are grouped in paniculate inflorescences or spikes that form between 400 to 8000 grains, and whose energy value is approximately 1.08 Mcal / kg.

The uses of these plants are mainly to make flours that are consumable by humans, as well as to make food for breeding and fattening animals. The panicles are also used to make brooms, and syrups and sugars are produced from the stems, among others.

characteristics

Appearance

These are plants with a rhizomatous or stoloniferous habit, annual or perennial. Plants of this genus develop a profuse root system that gives them a well-developed support to be able to accumulate many reserves.

In addition to this, this root system allows greater penetration capacity into the soil, and greater resistance to dry climates where water stress can last for a long time.

They develop culms (thick stems) about 60 to 300 cm tall. These culms are herbaceous in nature, slightly branched or with some higher branching. Culm internodes can be solid or hollow.

The genus Sorghum can have cultivable and other wild species. Source: pixabay.com

Leaves

The leaves are alternate, serrated, linear or lanceolate, and can be wide or narrow (without cordate or sagittal shape). They present persistent cross venation, and the shoots appear rolled up.

In this type of plants the presence of ligule is characteristic. The leaves can chitinize in dry periods and delay the desiccation of the plant.

flowers

Sorghum plants develop spike or panicle-shaped inflorescences, some species are hermaphroditic and male, and others are hermaphroditic and sterile.

Male and female spikelets of Sorghum bicolor. Source: Stefan.lefnaer

Paired spikelets can be sessile or pedicellate, long or short. The shortest are hermaphroditic, while the longest are male or sterile.

Each panicle forms between 400 to 8000 grains, whose energy value is approximately 1.08 Mcal / kg, its protein content is higher than that of corn, but it is poorer in terms of fat.

Grain

The color of the grain can be translucent white varying to reddish brown. In this variation, sorghum can present colors such as pink, yellow, red, brown. The shape of the grain or seed is spherical and oblong, and they measure more or less 3 mm.

The ears of Sorghum spp. they can have white to reddish brown grains. Source: pixabay.com

Allelopathy

Sorghum, like other plants, exerts a detrimental or beneficial effect directly or indirectly on other species, due to the release of chemical compounds especially from its roots.

This crop can protect the space it occupies around each plant. To do this, sorghum through its roots releases toxins into the soil, which inhibits the growth of other plants around it.

This released compound, or toxin, is known as sorgoleone, and it is known to be more active in fighting weeds than other allelopathic substances produced by other plants.

Specifically, this plant produces sorgoleone at its root and root hairs, and thanks to this compound, the maintenance and cleaning of the crop is easier.

Physiology

As in other C4 grass plants, sorghum species possess the enzyme phosphoenolpyruvate carboxylase, responsible for maintaining photosynthetic efficiency under conditions of water stress. This is because this enzyme has the ability to capture large amounts of carbon dioxide and supply it during the photosynthesis process.

On the other hand, the sorghum tissue, when suffering from water stress, responds with a stomatal closure to avoid or reduce in this way the loss of water. You can also adjust the osmotic potential of the cell so that the water potential is reduced, thereby maintaining the fluidity of the water.

In addition, sorghum can enter a phase of vegetative dormancy when the amount of water is not sufficient for its development. In this way, sorghum species begin a dormant phase, which ends when water is available again.

Taxonomy

-Kingdom: Plantae

-Filo: Tracheophyta

-Class: Liliopsida

-Order: Poales

-Family: Poaceae

-Gender: Sorghum

Some of the species of this genus are: Sorghum almum, Sorghum bicolor, Sorghum bulbosum, Sorghum controversum, Sorghum grande, Sorghum halepense, Sorghum instrans, Sorghum laxiflorum, Sorghum nitidum, Sorghum plumosum, Sorghum stipoideum, Sorghum virgatum, Sorghum versicolor, among others.

The ears of sorghum are also used to make brooms. Source: pixabay.com

Habitat and distribution

Sorghum includes both cultivable species and wild species. It grows in tropical regions, in warm climates and where there is an incidence of water stress.

Its distribution is cosmopolitan. It can grow in meadows, hillsides, savannas, streams, valleys, vacant lots, or as a weed in the field.

Reproduction

Sorghum flowers are pollinated by insects or by the wind. These plants are mainly self-pollinated, that is, a plant only accepts pollen from its own flowers.

However, sorghum can also reproduce thanks to pollen from other plants (cross pollination). Pollen is viable between 3 and 6 hours in the anther, while outside it it can last 10 to 20 minutes.

The fertilization process lasts 2 hours, and the maturation of the grain can take up to 35 days after that process.

Nutrition

In general, the cultivation of sorghum species should have a suggested fertilization according to the soil analysis and the characteristics of each species. However, the recommendation that is normally used is 90-60-30 kg / ha of nitrogen, phosphorus and potassium, respectively.

On the other hand, if fertilizer with the 10-30-10 NPK formula is used, it is necessary to add 184 kg per hectare at the time of sowing, and 22 days after emergence apply either 174 kg of urea, 242 kg of nitrate of ammonium or, in the case of ammonium sulfate 372 kg.

In this way, nitrogen extraction increases in accordance with the increase in yield, and as nitrogen concentrates in various structures of the plant.

Sorghum can be processed to increase the nutritional value of feed supplied to animals such as poultry, cattle and pigs, or some pets. This crop is high in cellulose, lignin, and carbohydrates, which makes it a great source of energy and high-quality protein for raising and fattening animals.

For example, in swine production, excess energy is stored as body fat, and this is the highest cost item in this commercial activity.

Applications

The panicle or ensiled ear, as well as the dry grain, is used as an energy source for feeding fattening pigs. On the other hand, sorghum is used for poultry feed through its concentrate, since this guarantees a good development and balanced growth. The concentrate of this grain combines carbohydrates, vitamins, minerals, proteins and fats.

Sorghum grains have many uses, especially to make feed for livestock. Source: pixabay.com

This plant has industrial purposes similar to those of corn. For example, starch, dextrose, edible oils, beverages such as beer, colorants, cosmetics, pharmaceuticals, paper, coffee mixes and meat products are produced from it.

On the other hand, the ears or panicles of this crop are used to make brooms, or go through a burning process to collect ash with a high concentration of potassium.

Otherwise, syrups and sugars, ethanol or sorghum flour are obtained from the stems to make cakes and cookies. Also, in some regions of Africa, India and China, the grain is broken and cooked like rice, or it is ground into flour that is used to prepare unleavened bread.

Featured species

Bicolor sorghum

This species is the representative of this genus. It is among the five most important cereals in the world along with rice, corn, wheat and oats.

It is an annual species with erect and robust culms, measuring between 3 and 5 m in height and up to 5 cm in diameter. The leaf sheaths are mealy. The grains are great.

In Africa, this sorghum is intended for human consumption, while in America and Oceania it is used to make flour and animal feed. It is widely distributed thanks to its ecological adaptability.

The agronomic advantages of this crop allow it to grow in less fertile soils, exert allelopathy, its maintenance requires little work and it is very competent in terms of its water economy to generate edible biomass.

Sorghum nitidum

It is a perennial species with erect culms that are 60 cm to 2 m tall. It has leaves with hairy veins or devoid of pubescence. Its leaf blades are linear, without trichomes and have lanceolate panicles.

Sorghum nitidum habitat. Source: Mark Marathon

The primary branches are whorled, the racemes are born at the ends of the most fragile branches and are made up of 2 to 4 spikelets.

This is a species that is distinguished in China and is not related to other species in that country. It is easily recognized by its bearded nodes and small shiny black spikelets.

Sorghum halepense

It is a perennial species with vigorously expanded rhizomes. Culms can be 0.5 to 1.5 m tall and 4 to 6 mm in diameter.

The veins of the leaves do not have pubescence, the leaf blades are linear or linear-lanceolate. The panicle is lanceolate in a pyramidal shape, with white and soft trichomes in the basal axilla.

On the other hand, the primary branches are solitary or extend in a spiral. The upper part is highly branched, while the lower part is bare.

It is a species native to the Mediterranean region, and is now distributed as a weed in many parts of the world. It can also be used as fodder with other sorghum species.

Sorghum halepense growing around a rice crop. Source: Matt Lavin from Bozeman, Montana, USA

Plagues and diseases

- Pests

Sorghum is highly attacked by specific pests of each agroecosystem, which behave as persistent and cause serious damage. Because of this, sorghum must be given sustained control as good soil preparation, combating weeds, balancing the alternation between hybrids and resistant varieties, eliminating crop residues, and making a wise selection of planting time.

Most pests are found in Africa and Asia, and the main ones that attack this genus are:

Sorghum mosquito (

This insect affects the flowers and the grain in formation.

Stem borer (

This species affects both the stems and the ears.

Aphids (

It is a species that affects the flowers and the grain in the formation stage, just like the sorghum mosquito.

- Stem fly (

It is an insect that damages the meristematic zone or growth point, thus causing necrosis.

- Jowar bug (

This bug causes damage to the seeds

Other animals that can affect this crop are birds, such as sparrows, which feed on the grains in the filling phase. Also, blackbirds and starlings consume the ripened grains.

Sorghum spp. Grains Source: pixabay.com

- Diseases

With regard to diseases, it has been described that they can affect grain production and decrease its nutritional quality.

Some suggestions to control diseases are using seeds previously treated with fungicides, sowing the recommended hybrids, respecting the recommended distances and planting densities in the winter and summer seasons, controlling weeds, fertilizing properly, eliminating crop residues and alternate crops.

Moldy grain (

It is a fungus that invades the tissues during flowering and causes the grains to fill less, therefore losses are increased.

Sorghum ergotism (

It is a fungus that behaves as a parasite, affecting flowers that have not been pollinated, which leads to a decrease in the quantity and quality of filled grains, and makes the harvest process difficult.

Moldy stored grain (

These fungi can damage the grain and cause inflorescence rot.

Bacterial streak (

It is a bacterium that attacks the leaf blade and prevents grain formation, thus causing a decrease in the harvest.

Stem and root rot (

It is a fungus that affects the filling of the grain and causes losses in yield.

Charcoal rot (

The effects are similar to those produced by Fusarium moniliforme.

References

1. Watson, L., Macfarlane, TD, Dallwitz, MJ 1992. The grass genera of the world. Taken from: delta-intkey.com
2. Shouliang, Ch., Phillips SM 2006. Sorghum Moench, Methodus, 207. 1794, nom. cons., not Sorgum Adanson (1763). Flora of China 22: 601-602.
3. Pérez, A., Saucedo, O., Iglesias, J., Wencomo, HB, Reyes, F., Oquendo, G., Milián, I. 2010. Characterization and potentialities of the sorghum grain (Sorghum bicolor L. Moench). Pastures and Forages 33 (1): 1-26.
4. Catalog of Life: 2019 Annual Checklist. Details of the genus Sorghum. Taken from: catalogueoflife.org
5. Sobetski, H. 2015. Pollination of sorghum. EDN number 126. Taken from: echocommunity.org