Cereals are grown all over the world, in all countries, in all climates, except for regions that are very hot and very humid (tropical countries). They are the plants with the greatest adaptability, with first and best the common or soft wheat and immediately after the durum wheat.
Out of the total of 14 billion acres cultivated with all plant species on a global scale, 7 billion (50%) are grown with grain. This in itself underlines the enormous importance of cereals for the global agricultural economy, nutrition and the survival of the entire population of the earth.
They are divided into cereals of the eucratic climates (autumn or winter) originating from semi-dry regions of sw Asia and the Middle East, and cereals of warm climates (spring) originating from warm regions of Southeast Asia, Central America, Central and Tropical Africa.
Autumn or winter grains include wheat (soft and hard), barley, oats and rye, which together occupy an area of 3.5 billion acres worldwide, of which 2.2 billion acres wheat, 0.8 billion acres barley, 0.3 billion acres oats and 0.2 billion acres rye or plug.
Autumn or winter cereals include another relatively new species, triticale, which is a cross between wheat and rye.
In the very cold regions of the earth, where temperatures during the winter fall too low, the grains of the temperate climates, despite their undeniable and proverbial resistance to low temperatures (they withstand temperatures up to -24oC), are sown in the spring so as not to be harmed by the very low temperatures of winter. Thus, we will find wheat, a classic winter plant, cultivated e.g., in Canada as spring, resulting in the creation of winter wheat varieties of winter growing habit and varieties of spring growing habit around the world.
Spring cereals include rice, maize, sorghum and millet.
Purpose of cultivation
Cereals are grown mainly for the production of fruit and secondarily for the production of biomass (maize – sorghum – millet – rye).
The main product of cereals is bread, for the preparation of which wheat (soft and hard, but mainly soft) and secondarily rye or risotto, because they are the species that have in their endosperm the proteins suitable for breading (mainly gluten). On the other hand, bread can be produced from the flour of all grains, even from the flour of sorghum and millet or oats, either as such or in combination with another grain, but it is not as good quality as the bread produced from the flour of soft wheat.
Another important product of cereals on a global scale is pasta, for the preparation of which is mainly used the flour of durum wheat (semolina) which due to the hardness of the endosperm from which it is produced, has the ability to keep the texture of pasta intact during boiling. The rest of the winter cereals (barley – oats – rye) are mainly feed grains, since their fruit is mainly used to meet the needs of animal production.
The world production of cereals (winter and spring) is huge and exceeds 2,100 million tons every year. Of this production, 650 million tons is currently the production of wheat (soft and hard), with the trend of cultivation being steadily increasing and production estimated at 720 million tons in 2019-2020.
The general trend of cultivation of barley on a global scale is steadily increasing. Barley is the fourth (or fifth) grain in a row of economic importance, after wheat, rice, maize and in some growing seasons, sorghum. On the contrary, slightly decreasing is the general trend of cultivation on a global scale of oats and rye. Triticales are anyway grown worldwide on a small scale.
Cereal production (excluding rice) in the European Union varies between 265 and 270 million tonnes each year, of which around 50% is wheat production. For 2014, the area cultivated with wheat is expected to reach 235-240 million acres in the European Union and production is estimated at 120-140 million tons, with the extremes representing the pessimistic (120 million tons) and the optimistic (140 million tons) scenario.
As far as the world cereals market is concerned, demand is increasingly focused on milled grains, with Europe remaining the most competitive market in the northern hemisphere in this sector.
Barley production in the European Union is forecast to be stable this year, at 54 million tonnes, from an area equal to 120 million acres.
In our country, wheat occupies every year an area of about 7-7.5 million acres (1.8 million acres for soft wheat and 5.0-5.5 million acres for hard wheat), with a production of 500,000 tons in soft wheat and 1,300,000 tons in durum wheat. Barley is cultivated every year in 1 million acres (fruit production 240,000 tons), oats and rye in 100,000 acres each, with a production of 10,000 tons each.
The average yields per hectare of winter cereals in our country are formed as follows: soft wheat: 270-300 kg, durum wheat: 240-260 kg, barley: 230-250 kg, oats and rye: 150 kg.
The cultivated species of wheat are eleven. More important, however, are soft (hexaploid) and hard (tetraploid) wheat. Lately, the cultivation of two-grained wheat (tetraploid), which is considered important for human nutrition, is rekindled.
Adaptability of winter cereals
Wheat is a plant of great adaptability and can be grown in almost all parts of the world. It can not be grown only in climates that are constantly warm and humid (diseases, difficult to harvest and store).
The best climate for wheat is the one that in the vegetative growth of the plant (increase of the stem) prevails cold and humid weather, and in the period of formation of seeds weather warm and dry. In semi-dry regions and Mediterranean climates it is cultivated as autumn or winter. In continental climates and large latitudes it is sown in the spring.
As already mentioned, the fruit of wheat, once floured, is mainly used for the preparation of bread and pasta, while the degraded qualities of the fruit (mainly soft wheat) are used in animal husbandry.
Barley is more resistant than wheat to high temperatures, but less resistant to low temperatures. It is more resistant than wheat to drought and more productive under dry conditions, because it has a smaller biological cycle and the lower transpiration coefficient of all cereals. It performs satisfactorily and in soils less fertile than wheat, while it requires less acidic soils. It is the most resistant to salinity of all grains.
In cold areas, barley is also sown in spring (from late February to mid-March) and completes its biological cycle soon, over a period of three months, which is why it is known as “quarters”.
Its fruit is used in animal husbandry and in the preparation of beer (malt-making), while the plant is suitable as a biomass plant and as a grazing plant.
Oats are the most sensitive species of all winter cereals to low temperatures, the most demanding in water and the least resistant to high temperatures. In salinity of the soil it is less resistant than barley and wheat, and more resistant than rice and maize.
The seed of oats is used as a fodder and for human consumption. It is advantageously used in the rations of solipeds. Oats are also grown for hay production, for grazing and for silage.
The rye or plug is the most resistant of all the grasses to low temperatures and the least demanding of all winter cereals in soil moisture, due to a highly developed root system. It is productive in poor, sandy, slightly acidic soils, resistant to obliqueness and weeds, so it does not require herbicide.
Rye is cultivated for fruit and biomass production. The fruit is mainly used for human consumption and as a fodder. For human consumption for bread production (dark color) mixed with wheat flour and for the preparation of biscuits, beer, whiskey, etc.
In the past, “mesingos”, a mixture of wheat and rye, was cultivated in Greece. The product before the war was used for the manufacture of bread.