Pepper, also known as the “king of spices,” is a culinary staple that has been used for centuries to add flavor and spice to dishes around the world.It is native to the area of Bolivia and Peru , where in addition to Capsicum annuum L. at least four other species were cultivated.
It was brought to Europe by Christopher Columbus on his first voyage (in 1493). By the 16th century, its cultivation had already spread to Spain, from where it was distributed to the rest of Europe and the world with the collaboration of the Portuguese.
Its introduction into Europe represented a culinary advance, as it came to complement and even replace another widely used condiment such as black pepper ( Piper nigrum L. ), of great commercial importance between the East and the West.
Taxonomy and morphology
Family: Solanaceae .
Species: Capsicum annuum L.
Plant: perennial herbaceous plant, with an annual growing cycle and a variable height between 0.5 metres (in certain varieties grown outdoors) and more than 2 metres (most hybrids grown in greenhouses).
Root system: taproot and deep (depending on the depth and texture of the soil), with numerous adventitious roots that horizontally can reach a length between 50 centimetres and 1 metre.
Main stem : with limited and erect growth. From a certain height (“cross”) it produces 2 or 3 branches (depending on the variety) and continues to branch dichotomously until the end of its cycle (secondary stems branch after sprouting several leaves, and so on).
Leaf : entire, hairless and lanceolate, with a very pronounced apex (acuminate) and a long, inconspicuous petiole. The upper surface is glabrous (smooth and soft to the touch) and of a more or less intense green colour (depending on the variety) and shiny. The main vein starts at the base of the leaf, as an extension of the petiole , as do the secondary veins which are pronounced and reach almost to the edge of the leaf. The leaves are inserted into the stem alternately and their size varies depending on the variety, with a certain correlation between the size of the adult leaf and the average weight of the fruit .
Flower : The flowers appear solitary at each node of the stem, inserted in the leaf axils. They are small and have a white corolla. Pollination is autogamous, although there may be a percentage of allogamy that does not exceed 10%.
Fruit : hollow, semi-cartilaginous and depressed berry, of variable colour (green, red , yellow , orange, violet or white ); some varieties go from green to orange and red as they ripen. Its size varies, and can weigh from a few grams to more than 500 grams. The seeds are inserted in a centrally arranged conical placenta. They are rounded, slightly kidney-shaped, pale yellow and vary in length between 3 and 5 centimetres.
Economic importance and geographical distribution
The success of peppers lies in the fact that they are a crop with three uses: fresh peppers, paprika and preserves.
The demand for fresh peppers in European markets throughout the year has grown spectacularly and has resulted in the development of greenhouse cultivation throughout the Spanish Mediterranean coast.
Pepper is one of the greenhouse horticultural crops with the largest cultivated surface area in Spain, with almost half of the production located in Almería , Alicante and Murcia .
Edaphoclimatic requirements
Rational management of climatic factors together is essential for the proper functioning of the crop, since they are all closely related and action on one of them affects the rest.
Temperature
It is a plant that is demanding in terms of temperature (more so than tomatoes and less so than aubergines ). The coincidence of low temperatures during the development of the flower bud (between 15 and 10 °C ) leads to the formation of flowers with some of the following anomalies: curved and undeveloped petals, formation of multiple ovaries that can develop into fruits distributed around the main one, shortening of stamens and pistil, thickening of ovary and pistil, fusion of anthers, etc. Low temperatures also induce the formation of smaller fruits, which may be deformed, reduce pollen viability and favour the formation of parthenocarpic fruits. High temperatures cause flowers and small fruits to fall.
Humidity
The optimum relative humidity ranges from 50% to 70%. Very high relative humidity favours the development of aerial diseases and hinders fertilization. The coincidence of high temperatures and low relative humidity can cause the fall of flowers and newly set fruit.
Brightness
It is a very demanding plant in terms of light, especially in the early stages of development and during flowering.
Floor
The most suitable soils for pepper cultivation are deep, rich, sandy loam soils with an organic matter content of 3-4% and mainly well drained. The optimum pH values range between 6.5 and 7, although it can withstand certain acidic conditions (up to a pH of 5.5); in sandy soils it can be grown with pH values close to 8. As for irrigation water, the optimum pH is 5.5 to 7. It is a species with moderate tolerance to salinity in both the soil and irrigation water, although to a lesser extent than tomatoes. In soils with a history of Phytophthora sp. it is advisable to carry out a disinfection prior to planting.
Irrigation
Moderate and constant in all phases of cultivation, although they tolerate occasional lack of water well.
Drip irrigation is ideal. Sprinkling is not, because wetting the leaves and fruits encourages the development of fungi.
Particularities of cultivation
Planting frames
The planting frame is established based on the size of the plant, which in turn will depend on the commercial variety cultivated. The most frequently used in greenhouses is 1 metre between rows and 0.5 metres between plants, although when it comes to medium-sized plants and depending on the type of training pruning, it is possible to increase the planting density to 2.5-3 plants per square metre.
It is also common to arrange paired crop lines, 0.80 metres apart, and leave 1.2 metre corridors between each pair of lines in order to facilitate the carrying out of cultural tasks, avoiding undesirable damage to the crop.
In greenhouse cultivation, the planting density is usually 20,000 to 25,000 plants/ha. Outdoors, the density usually reaches 60,000 plants/ha.
Training pruning
It is a common and useful cultural practice that improves greenhouse growing conditions and, as a result, produces higher commercial quality crops. Pruning results in balanced, vigorous and airy plants, so that the fruits are not hidden among the foliage, while being protected from sunlight. The number of stems that the plant will develop is limited (normally 2 or 3).
If necessary, the leaves and shoots that develop under the “cross” will be removed. Formative pruning is more necessary for early varieties of pepper, which produce more stems than late varieties.
Hilled up
Practice that consists of covering part of the trunk of the plant with soil or sand to reinforce its base and encourage root development. In sandy soils, this should be delayed as long as possible to avoid the risk of burns due to overheating of the sand .
Unpacked
Throughout the growing cycle, the inner stems will be removed to encourage the development of the stems selected in the training pruning, as well as the passage of light and ventilation of the plant. This pruning should not be too severe to avoid as far as possible vegetative stops and burns on the fruits that are directly exposed to sunlight, especially in periods of strong sunlight.
Leafless
It is recommended both for senescent leaves, in order to facilitate aeration and improve the colour of the fruit, and for diseased leaves, which should be immediately removed from the greenhouse, thus eliminating the source of inoculum.
Fruit thinning
It is usually advisable to remove the fruit that forms at the first “cross” in order to obtain fruits of greater size, uniformity and precocity, as well as higher yields. In plants with little vigor or hardened by cold, high salinity or unfavorable environmental conditions in general, very small and poor quality fruits are produced that must be eliminated by thinning.
Plague
Red spider
The species mentioned is the most common in protected horticultural crops, but the biology , ecology and damage caused are similar, so the three species are addressed together.
It develops on the underside of the leaves, causing discolouration, specks or yellowish spots that can be seen on the upper surface as the first symptoms. With higher populations, desiccation or even leaf loss occurs. The most serious attacks occur in the first phenological stages. High temperatures and low relative humidity favour the development of the pest. In beans and watermelons with high levels of pests, damage to the fruit can occur.
Preventive control and cultural techniques
Disinfection of structures and soil prior to planting in plots with a history of red spider. Elimination of weeds and crop residues. Avoidance of excess nitrogen . Monitoring of crops during the early stages of development.
Disease
Oidiopsis or Leveillula taurica (Lev.) Arnaud
It is a semi-internal parasite and the conidiophores emerge through the stomata. In Almería it is important in pepper and tomato crops and has been seen sporadically in cucumbers. The symptoms that appear are yellow spots on the upper surface that become necrotic in the centre, with a whitish felt on the underside. In case of strong attack the leaf dries up and falls off. Wild Solanaceae act as a source of inoculum. It develops at 10-35 °C with an optimum of 26 °C and a relative humidity of 70%.
Preventive control and cultural techniques: elimination of weeds and crop residues. Use of healthy seedlings.
Application of bioproducts and NPK
- Bovine manure: Before sowing, spread and manually.
- NPK: At the time of sowing and according to the agrochemical service, in a localized and manual manner.
- Foliar humus: By spraying, one application at the time of transplant and another at the beginning of flowering, using a backpack and manually. Both the container and the water for the suspension must be free of chemical products.
- Biopesticides: In the doses, mode and time of application according to the Manual for Organoponic and Intensive Gardens(MINAGRI, Cuba, 1999). They do not constitute a variation factor and will be applied equally to all treatments and experiments.
Harvest
Prices and demand on the one hand and temperatures on the other are the factors that will determine the time and frequency of this operation, harvesting before physiological maturity in green or red as appropriate.
Nutritional value
Fresh pepper fruit is notable for its high content of vitamins A and C and calcium . Depending on the variety, it can have different contents of capsaicinoids, alkaloids responsible for the spicy taste, and carotenoid pigments.
Marketing
The Lamuyo pepper is the most widely grown in Spain , although the demand for California peppers has increased significantly in recent years due to increased consumption in the European market , reaching up to 50% of national production.