Triticum aestivum
Triticum aestivum
Common wheat (Triticum aestivum L.) is a herbaceous species belonging to the Poaceae family.
Systematics –
From the systematic point of view it belongs to the Eukaryota Domain, Reign Plantae, Sub-Trinchega, Subdivision, Subclass Commelinidae, Poales Order, Poaceae Family, Triticeae Tribe and therefore to the Triticum Genus and to the Species T. aestivum.
The term Triticum vulgare L. is synonymous
Etymology –
The term Triticum according to Varrone derives from tritum battuto, for the use of beating wheat to separate the grains from the spikes, the specific epithet aestivum derives from summer, summer, from summer aestas.
Geographical Distribution and Habitat –
Soft wheat has been known since ancient times and was one of the first large-scale crops cultivated. Its origin is to be placed in that area called “Fertile Crescent” between the Tigris and the Euphrates. It is currently cultivated on all continents and world production has steadily increased in recent years. The main producers of soft wheat are China and Canada.
Description –
Triticum aestivum is characterized by having collated roots, with seminal and adventitious roots. The seminal roots are those that originate, in numbers from 3 to 8, directly from the embryo; these are thin, very rich in root and very branched hairs. The adventitious roots instead develop after the seminal ones since the young seedling issued the 3rd – 4th leaf; these roots sprout just below the surface of the soil, from the nodes to the base of the culms: they are very numerous and developed, so much so that they constitute the great mass of the root system. The deeper roots serve for the supply of water and mineral salts with a depth that depends on the nutritional state of the plant and the nature of the soil and normally ranges between 25 and 35 cm from the surface.
The stem is erect and is a culm is provided with leaves and at the lower end of inflorescences and has a circular section, with decreasing diameter from the base to the apex and in the inner part, in correspondence of the internodes, it is usually empty. The culm consists of nodes and internodes; from the nodes the leaves originate, constituted by a sheath enveloping the culm itself. The number and length of the internodes, the width and bearing of the leaves, the diameter and thickness of the culm are changing characters with the species, the variety and with the cultivation conditions. They have importance, in particular as regards the morphological and anatomical features of the culm, for the resistance and susceptibility of the plant to diseases such as lodging. The height that can be reached by the culms of wheat varies greatly with the state of nutrition of the plant and, especially with the variety: from 60–70 cm of the dwarf varieties to 160–180 cm.
At the apex of the culm there is an ear, which has simple sessile flowers, that is attached directly to the axis. Each ear consists of a rachis, formed by short internodes, which carry a spikelet to each tooth. Each spikelet is formed by two glumes, which contain different flowers, not all fertile, each containing an ovary and three anthers. Each of the flowers is protected by two glumettes, one lower and one upper. In the inner part of the inferior glumetta there are two lodicles (scales that, after swelling, cause the opening of the glumettes).
After fertilization, the grain or grain is a caryopsis, meaning it has no seeds distinct from the rest of the shell. It is a dry indehiscent fruit which, therefore, opens when fully ripe. This has an ovoid shape and is composed of the embryo or germ, of the integuments or endosperm that protects the seed and of the envelope containing starch, starch glutimido and proteins. The embryo, even if it represents a small part of the grain, has an essential task for the of the reproduction of the species. This mainly contains fats, nitrogenous substances, enzymes, vitamins and hormones. The shape, size and appearance of the caryopses change with the species and the variety.
Cultivation –
Common wheat is an autumn-spring cereal and its cultivation benefits considerably from crop rotation. The cultivation of maize, beet, tomato, potato, sunflower, broad bean, cotton (even the rice that leaves the soil free of weeds) is a good cultural precession because wheat is able to use the residue very well of fertility left in the soil by such crops, better still if it is not other cereals.
Instead it is not the best crop to use the high fertility left by the multi-year meadows (legumes and grasses). In the arid areas, the succession of fallow wheat is traditional, mineralizing the soil with organic substance and enriching it with water. The succession to a renewal crop also allows a less deep working of the soil.
The biological phases of soft wheat are as follows. Germination takes place with a temperature of a few degrees above zero, with sufficient humidity and air; in these conditions the caryopsis absorbs water, swells and starts a series of synthetic reactions. The germination phase lasts 15-20 days and begins with the breaking of the granule coating shells at the embryo and with the subsequent appearance of the primary radicle, which develops and escapes into the ground followed by other embryonic roots. With this the germination took place, later on other other embryonic roots will sprout up to 8. Subsequently, the stem of the plant is lengthened up to the level of the ground, from which a plumule comes out which extends and takes place in the first leaf to which the second and third. At this point, an enlargement or knot forms at ground level, from which other roots grow. The set-up phase begins.
The preparation is the phase in which the plant develops the secondary root system and forms culmination of ripening from which then the shoots will be born. This phase is called creeping, since the plant does not rise but remains close to the ground, a very important fact for the wheat which, being an autumn-winter cycle cultivation, needs to be close to the ground in order to withstand the harsh winter climates. During this phase there is also the accumulation of organic substances for the subsequent development phases. When temperatures are high enough, the drooling phase begins.
The lifting phase is represented by a fast and rapid process, as the water and mineral salt consumption reaches very high values; it is precisely at this time that we have the greatest synthesis of dry matter. The rising phase is characterized by the raising of the culm and the lengthening of the internodes, starting from the lowest one. The ear, which is found at the apex of every shoot wrapped in the sheaths of the leaves of the internodes in the course of elongation, increases and rises during the rising. When only the last internode remains to be stretched, the ear is covered only by the sheath of the last leaf and, having almost completed its development, causes a characteristic enlargement of the sheath itself: this is a step of the wheat called Botticella.
With the earing, the inflorescence emerges from the sheath of the last leaf. After a few days there is the flowering that begins in the spikelets starting from the lowest flower. Fertilization is autogamous because it takes place before the opening of the glumelles.
Once the fertilization has taken place, the phase of maturation begins, which begins with the enlargement of the ovary and, therefore, with the formation of the caryopsis. At first the embryo is formed, followed by the accumulation of the reserve substances, after which the caryopsis swells rapidly until it reaches the volume of the mature grain. There is then a considerable loss of water.
Maturation can be divided into 4 successive stages which are:
– milky maturation: The plant is still green, as are the grains, which contain a more or less dense milky liquid and a lot of water. The caryopsis is fragile;
– waxy ripening: There is an advanced yellowing, but not total. Only some parts of the plant are still turgid and vital. The caryopses, lacking in chlorophyll, take on a waxy consistency a little more solid than the previous phase. There is still an accumulation of reserve substances and there is still a fair amount of water with a humidity of 40%.
– Fiosiological maturation: The whole plant is yellow and dry; the caryopses, also yellow, have a more solid structure. In the granules the percentage of water is 25-30% and the accumulation of reserve substances is finished.
This phase is the best one for harvesting.
– full maturation: There is a further loss of water in the grains (12-13% content). However, the culm and the spine are fragile and there is a risk of leakage in the collection. The humidity must be less than 14% otherwise the plant will rot.
Uses and Traditions –
Common wheat is the species of wheat which, due to its wide use in bread-making and the production of fresh pasta, takes on greater importance among the cereals in cultivation today. Triticum aestivum is an hexaploid with BAD genomes, 2n = 42; is derived from the hybridization of a cultivated subspecies of Triticum turgidum (durum wheat) and the pollen of a wild species, the Aegilops tauschii. Soft wheats include different varieties and have a wider cultivation extension than other wheats because, due to their good resistance to cold, they are the only ones in cultivation in the Nordic countries.
The modern varieties of soft wheat are the fruit of continuous improvement work carried out mainly by using the intervarietal crossing, with the aim of perfecting the most important features for the purpose of increasing productivity and quality.
– Precocity. The earliness was extremely advantageous because by anticipating the end of the cycle it allowed us to escape the dangers of drought and thermophilic rust (r.nera and r. Bruna). However the precocity cannot be pushed beyond certain limits because it involves an increase in sensitivity to the cold and to spring frosts.
– Resistance to lodging. It is made by lowering the height of the plants by exploiting “dwarfing” genes that reduce the length of the internodes of the culms without reducing the number.
– Resistance to cold. The availability of varieties increasingly resistant to the cold has reduced the risk of winter mortality and has even allowed to pass to the autumn sowing in regions where there was traditional spring sowing.
– Disease resistance. Resistance or genetic tolerance to cryptogamic adversities is the best way to avoid production losses caused by these without having to resort to pesticide treatments.
– Grain quality. The current varieties are well characterized for their response to the various uses of common wheat.
Great importance is given to bread making, that is the ability of a flour to make good quality bread. The consistency and appearance of the endosperm, which may appear amber, vitreous, mealy, white, tender, depending on the species, the variety and the culture environment are of considerable importance with respect to the quality of the product and its use.
The nutritional values per 100 grams of edible part of soft wheat are as follows: Kcal 317.00, Calories from protein 16.00%, Calories from carbohydrates 77.00%, Calories from fat 7.00%, Water 12.00 g, Proteins 12.30 g, Carbohydrates 65.20 g, of containing soluble sugars 3.30 g, starch 56.30 g, fats 2.60 g, of which saturated 0.60 g, monounsaturated 0.29 g, polyunsaturated 1.59 g, total fiber 9.70 g, Sodium 2.00 mg, Thiamine (B1) 0.41 mg, Riboflavin (B2) 0.10 mg , Niacin (B3) 4.76 mg, Vitamin A (Retinol eq.) 0.00 µg, Vitamin C 0.00 mg, Vitamin E 1.44 mg, Calcium 34.00 mg, Iron 5.37 mg, Phosphorus 402.00 mg, Magnesium 90.00 mg, Potassium 435.00 mg, Copper 0.42 mg, Zinc 3.46 mg, as well as various amino acids and other substances in smaller quantities.
Preparation Mode –
Common wheat flour derives from the grinding and subsequent refinement of wheat kernels.
The uses of flour in the kitchen are multiple for the preparation of bread, pasta, cakes, desserts, but it is also necessary as a thickener for sauces or for the preparation of meat and fries.
Soft wheat flour is white flour that is most widely used for the preparation of egg pasta, bread and derivatives, sweets. Depending on the degree of refining, soft wheat flour can be of type:
– integral: the wheat is ground with the outer covering membranes, it is rich in bran and more complete from the nutritional point of view for mineral salts and vitamins; it is usually used to prepare wholemeal bread or pasta;
– type 1 and type 2: they are less white, of thin grain, and contain more parts of bran, starches and proteins; they can be used for bread or pizza;
– type 0 (zero): of fine grain, has only a small percentage of bran; it is generally used for bread or pizza;
– type 00 (double zero): impalpable and very fine, without bran and very white; it comes from the grinding of only the internal part of the seed and for this reason being rich in starch and proteins, it is however poor in mineral salts, vitamins and fibers; it is generally used for the production of pasta, pizza, desserts and as a thickener.
Guido Bissanti
Sources
– Acta Plantarum – Flora of Italian Regions – Wikipedia, the free encyclopedia – Treben M., 2000. Health from the Pharmacy of the Lord, Advice and experiences with medicinal herbs, Ennsthaler Publisher – Pignatti S., 1982. Flora d ‘Italy, Edagricole, Bologna. – Conti F., Abbate G., Alessandrini A., Blasi C. (edited by), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
Attention: Pharmaceutical applications and food uses are indicated for informational purposes only, do not in any way represent a medical prescription; therefore no responsibility is assumed for their use for curative, aesthetic or food purposes.