Tomatoes. Biological features of tomato
Tomato is a sun-demanding crop. Plants grown in protected soil and varieties of southern origin especially need light. Most tomato varieties of southern origin are short-day, while northern tomato varieties are day-neutral or long-day. With a lack of light, especially during the period of growing seedlings, the plants become very elongated, their development is delayed, and few buds are formed. In addition, the plants bloom poorly, the flowers are poorly pollinated, and the ovary falls off. The dry matter content in fruits, the ratio of acids to sugars, the content of vitamins, etc. also depend on lighting. Therefore, plants should not be placed in shaded areas, and if there is a lack of light, additional illumination is carried out, which increases the productivity of plants.
Tomato is a heat-loving plant. Heat is one of the main factors and largely determines the growth rate, ripening and yield of tomatoes. The optimal temperature for seed germination is 20-25°C, the minimum is 10-12°C. The most favorable temperatures for plant growth are 22-24°C during the day and 16-18°C at night. At 8-10°C the growth and maturation of pollen stops, at 15°C flowering occurs. Temperatures above 30°C (as well as low temperatures) retard plant growth and cause buds and flowers to fall off. Germinating seeds can withstand temperatures down to -10°C until seedlings appear, seedlings and young plants can withstand temperatures of minus 0.5°C, and temperatures of 1-2°C are detrimental for plants. Young plants from hardened seeds, as well as those grown without seedlings, tolerate short-term frosts down to -4°C. A night air temperature of 10-12°C increases the degree of branching of the raceme, its compactness and promotes the formation of a larger number of flowers, while at a night temperature of 22-24°C a smaller number of flowers are formed on longer and thinner axes of the inflorescence. In open ground, a tomato ripens only when the sum of positive temperatures is above 10°C (for the period from early June to mid-August) 2150-2700°C or more.
Soil moisture for tomatoes is somewhat less important than heat. At the same time, in order to form a powerful root system and above-ground biomass and obtain a rich harvest, a large amount of water is required. The critical periods in water consumption are the initial period of growth and the period of formation and filling of fruits. Watering at this time is necessary and most effective.
The optimal soil moisture for tomatoes is 70-80% of the full field moisture capacity. With a lack of water in the soil, the absorption of mineral nutrition elements by the root system deteriorates, leaves lose turgor, growth processes slow down, buds and ovaries fall off, fruit filling stops and, as a result, a decrease in yield occurs. Excessive soil moisture weakens plant resistance to disease.
Air humidity is of great importance for the normal development of tomatoes. It should not exceed 50-60% (in the first 10-12 weeks it should be within 60-65%). At higher relative air humidity, pollination of flowers worsens, they fall off, plants are more susceptible to fungal diseases (seedlings - blackleg, plants and fruits - late blight), plants become elongated, and their yield decreases. With high air humidity and excess nitrogen nutrition, the inflorescence can grow, i.e. leaves and even new shoots with inflorescences can grow on it. The room where tomatoes grow should be intensively ventilated.
Tomato plants are less demanding on soil than many others. vegetable crops, however, it is better to give them well-warmed fertile soils, rich in organic matter, with a pH of at least 5.5. Sandy loam and light loamy soils in mechanical composition, with a high content of humus and nutrients.
The need for nutrients changes during the growing season. In the first period (before the formation of fruits), plants use only 5-7% of the total consumed amount of nutrients. As the green mass increases and especially the formation and growth of fruits, the consumption of nutrients increases sharply. During this period, increased plant nutrition is necessary, especially in protected soil. With mineral starvation, the leaves become blue-green, then grayish, and the stems become lilac-brown. Tomatoes are very sensitive to phosphorus deficiency, especially during the initial growth period. Almost all the phosphorus consumed during the growing season is then used to form fruits. Nitrogen is necessary for the formation of vegetative mass, but its excess can lead to a strong increase in green mass, that is, plants become “fatten” to the detriment of fruiting. Potassium is necessary for the formation of tomato stems and fruits, and calcium stimulates the growth of roots and stems. Microelements such as magnesium, sulfur, iron, boron, manganese, copper, etc. are also necessary for the normal growth and development of tomato plants.
At favorable conditions Tomato seeds germinate on the 3-4th day after planting (however, there are varieties, especially among giants, in which germination occurs later - on the 5-10th day; old seeds also germinate more slowly). First, they develop a root and penetrate into the soil, then they emerge from the soil and the cotyledon leaves immediately open. The first true leaf appears after 6-10 days, the next 3-4 leaves - every 5-6 days, and then each new leaf - after 3-5 days. At one month of age, plants usually have 4-5 leaves. Formation is especially intensive. root system, which in 40-day-old plants penetrates to a depth of 80 cm and branches.
Flower clusters are formed above the 7-9th true leaf in early-ripening varieties and above the 12-14th in late-ripening varieties, approximately 30-60 days after emergence. From this time on, the process of budding and vegetative growth proceed in parallel, in most varieties it does not stop almost throughout the entire growing season, when the plant can simultaneously have leaves, stepsons and flower clusters with buds, flowers, ovaries and fruits of varying degrees of maturity.
Starting from a young age, tomato plants form side shoots in the axils of the leaves - stepsons. Based on the nature of growth and type of branching, two groups of tomato plants are distinguished (Fig. 1). In most varieties, the apex of the plant, after the formation of 7-14 leaves, ends in a flower raceme, and the stepson growing from the axil of the leaf closest to the apical raceme continues the growth of the main stem (lateral or sympodial branching). After the formation of several leaves (1-6), the stepson ends its growth by laying a flower raceme, and the growth of the plant continues at the expense of the nearest stepson. And so on until the end of the growing season, which usually ends with the first autumn frost. The type of bush with unlimited growth is called indeterminate (Fig. 2). In some low-growing varieties, plant growth ends with a brush, and stepsons are formed only in the lower part of the stem. The type of bush with limited growth is called determinate (Fig. 3).
Rice. 1. Features of growth and branching of a tomato stem: a - monopodial branching; b — removal of the leaf above the inflorescence during the growth of the first sympodium; c - sympodial branching; C - cotyledons; L - leaf; Social—inflorescence
Tomato varieties with an indeterminate growth type are divided into 3 groups:
- early ripening, weakly repairable. They are distinguished by a strongly pronounced attenuation of growth processes during the period of crop formation on the first inflorescences, friendly early fruiting, as well as noticeably expressed unevenness in the formation and yield of the rest of the harvest; the yield is quite low; the inflorescence of this group is, as a rule, simple, unbranched (there are varieties in which the first inflorescence is complex); medium weight fruit;
- mid-season, mid-repair. They are distinguished by less pronounced attenuation of growth processes and a more uniform supply of crops during the fruiting period; inflorescence simple or branched; medium weight fruit;
- late-ripening, highly remontant. They have strongly expressed growth processes, which are practically not affected by the developing fruits of the first inflorescences; yield is uniform throughout the entire fruiting period; inflorescences - from simple bilateral to complex.
Rice. 3. Layout of the arrangement of leaves and inflorescences on the main shoot of superdeterminate (a), determinate (b) and semi-determinate (c) tomato varieties
Tomato varieties with a determinate growth type are also divided into 3 groups:
- early ripening superdeterminant. 2-3 inflorescences are formed on the main and side shoots, and plant growth stops for a long time. As a result of weak remontancy and limited growth of shoots by inflorescences, the plant forms a small compact bush. The second weakened wave of plant growth is observed after most of the fruits have ripened. The height of the first inflorescence is the 6-7th leaf. Between two subsequent inflorescences on replacement shoots there is 1 leaf, less often - 3, and sometimes the inflorescences follow directly one after the other. The yield of the harvest is very smooth, but the yield is low;
- mid-season determinant. Plants of this type are characterized by limited growth of replacement shoots after the formation of 4-6 inflorescences on them. The second wave of growth in varieties is more pronounced and occurs much earlier - after the completion of fruit formation on the first inflorescences. The height of the first inflorescence is the 8-9th leaf. Subsequent inflorescences follow through 1, often through 2 leaves. This is the most numerous group of determinate tomato varieties used in production. Determinate varieties begin to bear fruit 5-7 days later than superdeterminant varieties; the duration of harvest and the overall productivity of varieties of this group are much higher;
- late-ripening semi-determinate. They are characterized by a weakened manifestation of determinism, i.e. long-term lack of restriction of stem growth (even after the formation of 8-10 inflorescences on it). Inflorescences are laid after 2-3 leaves. The first inflorescence is located after the 10th leaf. This is the latest ripening group of determinate tomato varieties. In terms of uniformity of yield, the yield is close to late-ripening, highly remontant tomato varieties with an indeterminate type of growth.
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And a little more biology
In the process of plant ontogenesis, vegetative growth and reproductive development are determined by various morphological characteristics, as well as environmental conditions, are in constant interaction and are inseparable. Therefore, the division of these processes is conditional. According to D.D. Brezhnev, tomato plants go through the following phases in their ontogenesis: the appearance of seedlings, the first true leaf, the growth of above-ground mass and roots, the formation of buds, flowering, the formation and ripening of fruits.
Under favorable temperature conditions and the presence of moisture, tomato seeds germinate 3-4 days after sowing; if there is a lack of heat, especially when sowing in open ground, after 2-3 weeks. After swelling, the seeds first develop a root, then the subcotyledonous knee begins to grow, which bends in the form of a loop, pierces the soil and, as it grows, brings the cotyledons to the soil surface. After the seedlings straighten and the cotyledon leaves open, further growth of the plant occurs due to the growth point of the stem.
In a tomato plant, under favorable conditions, in the first 2-3 weeks after germination, the growth of the root system predominates, and the cotyledon leaves grow slowly. When grown without seedlings, as well as at low temperatures in seedling structures, this period is longer. The first true leaf is formed after 6-10 days. Increased temperature in this phase accelerates the appearance of true leaves and promotes elongation (growth) of the hypocotyledon, which is undesirable.
Subsequent leaves are formed after 5-6 days, and then faster - every 3-5 days. When the 1st and 2nd true leaves appear, the seedlings are replanted in protected soil, which contributes to the development of a more powerful root system and seedlings of better quality. After replanting, when the plants take root and begin to grow intensively, new leaves appear and fruiting organs (buds of tubercles) are formed. The buds are formed after the formation of 3-4 true leaves. At one month of age, tomato plants have 4-5 leaves. Simultaneously with the growth of leaves, the growth of stems and roots occurs. When a young plant forms a sufficiently developed root system, intensive growth of the above-ground mass begins. The fastest growth of seedlings is observed before planting them in the ground. After planting seedlings in open ground for 7-10 days, and if the quality of seedlings is poor - up to 20 days, the mass of the plant does not increase (often even decreases), restoring the damaged root system and rebuilding the physiological orientation of metabolic processes in relation to open ground. The higher the quality of the seedlings and the better the root system is preserved during planting, the shorter this period. In the future, the growth rate of the tomato plant largely depends on the variety and cultivation technology.
Flower clusters are formed above the 7-9th true leaf in early-ripening varieties and above the 12-14th leaf in late-ripening varieties, approximately 30-40 days after emergence. From this time on, the process of bud formation and vegetative growth proceed in parallel, without stopping almost throughout the entire growing season and fruiting; the budding phase lasts about 15-20 days. The duration of the period from the emergence of seedlings to the beginning of flowering varies widely: for early ripening after 40-50 days, for mid-ripening - 51-70, late ripening 71-90 days. Development rates depend on temperature environment. This is especially true when growing tomatoes in open ground.
The tomato is a self-pollinating plant, in which one flower contains male and female organs. This is due to the structure of its voluminous flower. The stamens, fused with the side walls of the anthers (male organ), tightly surround the pistil ( female organ), consisting of an ovary with an ovule and a style with a stigma. When the pollen ripens, the stamens open from the inside and the pollen spills out onto the stigma of the same flower. This is how self-pollination occurs, which usually coincides with the opening of the bud. Next, the pollen penetrates through the style into the ovary and ovule, where fertilization occurs. Then the ovule develops into a seed, and the ovary into a fruit.
In the southern regions, during hot, dry weather, 2% of plants experience natural cross-fertilization (pollen from other flowers). In this case, pollen is carried by bees, bumblebees, thrips, and ants. This is observed when the stamens with anthers develop shorter and the style with the stigma turns out to be higher than them. In this regard, in the southern regions, seed crops are isolated in open areas by 300 m and in protected areas by 100 m, variety from variety. In woodland and forest-steppe this insulation can be reduced to 100 and 40 m, respectively.
Self-pollination in tomato is favored by the fact that the receptive stigma is located inside the anther cone, and the flower occupies a hanging position. Tomato pollen has a diameter of 21-24 microns. The fusion of sperm and egg occurs 35-50 hours after pollination.
Flowering begins from the first brush and goes from bottom to top. The second brush at this time is in the budding stage and blooms only after 6-15 days. The third cluster blooms about a week after the second, the fourth - a week after the third, etc. In each cluster, the lower 2 flowers open first, followed by those above them, opening in pairs. From the beginning to the mass flowering of the brush (75% of opened flowers) it takes from 2 to 6 days.
The stigma of a flower becomes receptive to pollen almost simultaneously with the maturation of the anthers (cracking of the latter usually occurs 24-48 hours later) and is capable of receiving pollen 9-12 days after the colored bud phase.
Despite the fact that the tomato is self-pollinating, not every flower produces an ovary, from which a fruit would subsequently form. This depends on the conditions in which the flowering and fruit formation phases take place. Under unfavorable conditions—drought, a sharp drop in temperature—mass falling of buds and flowers is often observed. In addition, cases of mass falling of flowers can be observed in greenhouses during autumn-winter rotation, that is, under shortened day conditions.
All types of tomato (cultivated, semi-cultivated and wild) and varieties can be crossed with each other very easily. For better pollination in room conditions dry air is required.
From the moment of fertilization, fruit growth begins, and upon reaching the size characteristic of the variety, ripening begins. From the beginning of flowering to the ripening of the first fruits of early ripening varieties, 35-45 days pass. For mid-ripening (46-65 days) and late-ripening varieties of tomato, this period increases to 66-85 days. The early maturity of a tomato is determined not only by the beginning of fruit ripening, but also by the share of the harvest during the first ten days of fruiting and by the presence of ripe fruits of the entire harvest, expressed as a percentage.
As the fruit ripens, a whitish tint of the skin appears, the flesh becomes light green with a pale pinkish tint, and the seed coat hardens (milky ripeness). Then the redness spreads to the skin and flesh of the fruit, causing a change in the external color to brown (brown, or blanzhevoy, ripeness), and then to pink and red (pink and full, or biological, red, ripeness). The seed chambers of the fruit are filled with cell juice in which the seeds are immersed, the fruit becomes juicy and soft.
The duration of the growing season of tomato varieties can vary significantly depending on the weather conditions of the soil and climatic zone, methods and technology of cultivation. This difference can reach 20-30 days. Growing season (from emergence to fruit ripening) different varieties varies greatly and is: for ultra-early ripening varieties 85-90 days, early ripening - 91-105, mid-early - 106-110, mid-ripening - 111-115, mid-late - 116-120, late ripening - more than 120 days
. When growing the same variety in the south and in the north, the growing season is shorter in the first case due to better heat supply.
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Tomato (Lycopersicon eculentum Mill.) belongs to the Solanaceae Pers. family, genus Lycopersicon Tourn.
Tomato – herbaceous annual plant, but in conditions favorable for growth, it can be perennial (Garanko I.B., Shtreis R.I., Goleshevsky L.F. et al., 1985).
Tomato is a perennial crop. Under appropriate conditions (for example, in the subtropics), plants can grow and bear fruit for several years. However, in agricultural practice, tomato is grown as an annual crop. During the life of a tomato plant, it goes through the following phases: emergence of seedlings, appearance of the first true leaf, formation of buds, beginning and mass flowering, beginning of fruit formation, beginning and mass ripening of fruits.
Tomato plants differ from other vegetables in having a highly branched root system. Young plants have a pronounced tap root. Roots of the first order extend from the main root, and roots of the second order depart from them. There are also roots of third and fourth order. All roots are covered with a dense mass of root hairs. With seedless tomato culture, the roots reach a length of 100...150 cm, individual roots penetrate to a depth of 2 m. The roots branch mainly at a depth of 55...85 cm, covering up to 1.25 m³ of soil. With seedling culture, the root system is located in the more superficial layers of the soil (Vegetable Growing in Russia, 2011 – 2012).
As noted by Zhukovsky P.M. (1971), the root system of tomato is highly developed and deeply penetrating. Tap root with big amount well branched side shoots. In the greenhouse, the bulk of the roots are located at a depth of up to 30 cm.
The tomato stem is branched, round, lodging or erect; at first very fragile, then very hardened, up to 14 m. The tomato does not have a single axial stem. The apparent single stem consists of separate lateral shoots of increasing orders of stepsons that successively replace each other. The main stem is conventionally considered to be the one on which the first inflorescence appeared (Krug G., 2000).
There are two types of sheet: normal (ordinary). In which the leaf surface is either smooth or corrugated, and potato type, in which the leaves have entire large lobes. Just like the stems, they are covered with glandular hairs.
The inflorescence is a curl. The flowers are small, inconspicuous, yellow in various shades, usually five-membered, but can also be multi-membered. Flowers with five petals are usually found in small-fruited varieties, and large-fruited varieties have more petals. There are usually five anthers, sometimes more, the stamens are fused in the form of a cone, the style is thread-like, ending with a pale green stigma (Vegetable Growing in Russia, 2011 - 2012).
Depending on the variety, the brush is complex or simple. Flowering of plants and opening of flowers on the raceme occurs from bottom to top. The flowers are bisexual (Brezhnev D. D., 1955; Tarakanov G. I., Mukhin V. D., Shuin B. A. et al., 1993).
Tomato is a self-pollinating plant. Flowering begins 50...70 days after germination and continues until the plants die (Vegetable growing in Russia, 2011 – 2012).
Tomato is a facultative self-pollinating plant. At high humidity and temperatures below 12 ºС, pollination of flowers does not occur. Self-pollination becomes difficult at air temperatures of 35 ºС and above, since the pistils elongate and protrude above the stamens (G. I. Tarakanov, O. D. Gutsalyuk, V. G. Korol, 1988; N. V. Nikiforova, 1989).
Ovary superior. Round, smooth or pubescent, bilocular or multilocular. The ovary, depending on the structure of the flower, is either small-lobed or multi-locular (Vegetable Growing in Russia, 2011 – 2012).
Brezhnev D.D. (1955) notes that the tomato fruit is a juicy, fleshy berry of varying weight, shape and color. Almost the entire internal part is occupied by a juicy placenta. The seeds are immersed in a gelatinous mass (pulp), formed from the contents of destroyed cells of the placental tissue during the period of fruit ripening. Fruit weight from 5 to 400 g. Fruits are three-, five-, and multi-chambered. The weight and chamberness of the fruit are important varietal characteristics.
Matveev V.P., Rubtsov M.I. (1985) believe that the tomato fruit is a complex two-, four-, or multi-chambered berry.
The seeds are small, triangular-reniform or obovate, flattened, pubescent, located in two or several chambers. The seeds are usually pubescent and therefore have a gray tint. Multi-chambered fruits, as a rule, have few seeds, and small-chambered fruits have many seeds. The seeds reach physiological maturity already in green, formed fruits. They remain fresh for 6...8 years or more (Vegetable growing in Russia, 2011 – 2012).
1 g contains from 220 to 300 seeds. Seed germination depends on storage conditions. The best conditions for long-term storage of seeds are air temperature 14 - 16 ºС, air humidity - not lower than 75%, seed moisture - 9% (Alpatiev A.V., 1950; Tarakanov G.I., Gavrish S.F., Andreeva E. N. et al., 1998).
Among the huge number of varieties and hybrids, three varieties of tomatoes are distinguished - ordinary, standard and large-leaved. An ordinary tomato has thin stems, which, as a rule, lie down under the weight of ripening fruits. The standard variety has thick, erect stems creating the appearance of a bush; the leaves have a corrugated surface and a short petiole. Large-leaved tomatoes have large leaf sizes, the only feature that distinguishes them from the ordinary tomato (Vegetable growing in Russia, 2011 – 2012). Depending on the nature of growth and branching of side shoots, tomatoes are divided into 2 groups:
Indeterminate (with unlimited growth) - first forming shoots (stepchildren) of the first order from the axils of the leaves of the main stem, then branching into shoots of the second order and so on without limiting growth. All these shoots produce clusters of flowers and bear fruit as long as favorable growing conditions exist.
Determinate (with limited growth) - forming lateral shoots only in the leaf axils of the lower part of the main stem, after which the bush stops branching.
Indeterminate require partial removal of side shoots (stepchildren) and garter. Determinate plants in open ground conditions, as a rule, do not require pinching (Bekseev Sh. G., 1962; Ignatova S. I., 1998; Skvortsova R. V., Kondratyeva I. Yu., 2001).
Tomato plants can reproduce vegetatively (shoots and cuttings take root easily) and by seeds. The latter is the main method used in tomato culture (Vegetable growing in Russia, 2011 – 2012).
tomato hybrid cultivation yield
The physiology of plants, their morphological and biological characteristics, underlie all technological actions and agricultural practices used in growing tomato.
For successful tomato growing, it is important to study the external shape and internal structure of plants in the process of their individual and historical development. (Bryantseva Z.N., 1964).
Tomato, tomato - a genus of plants of the nightshade family, 3 species are known: Peruvian tomato, hairy tomato, ordinary or true tomato, including several varieties with edible fruits, unknown in the wild. This species includes all cultivated forms of tomato. (Dmitrieva O.M., 1988).
The common tomato is grown as an annual plant, but can grow for several years if protected from frost. The root is taproot, but quickly branches, penetrating up to 1-2 m deep, depending on the method of cultivating the soil and the variety.
The seeds are flat, kidney-shaped, grayish-yellow in color, heavily pubescent. 1 g contains from 220 to 300 seeds. Germination is well preserved for 5-7 years, and if certain conditions are met (constant air temperature 14-16 ° C, humidity not lower than 75%), they germinate in the 10th and even 20th year of storage. (Gavrish S.F., 2003)
When seeds germinate, the embryonic root appears first.
The root allows the tomato seedling to quickly gain a foothold in the soil and provide the plant with an influx of new nutrients. The main root develops from the embryonic root. Lateral roots appear on the sides of the main root, which give rise to roots of the second and subsequent orders. All of them are covered with a large number of root hairs.
The root system of a tomato plant depends on the characteristics of cultivation and the variety of crop. When sowing seeds in the ground, the taproot grows into the soil depth up to 1.4-1.8 m. The diameter of the root system in this case is 1.5-2.5 m. When cultivating tomato seedlings, the root system is fibrous. Its bulk is located in the upper layer of soil 0.5-0.7 m thick. In protected soil, the root system is located in a substrate whose thickness does not exceed 0.3 m.
A tomato, in addition to main and lateral roots, is also capable of forming adventitious roots, which form anywhere on the stem if it is sprinkled with moist soil. This allows you to root individual parts of the stem, or, for example, stepsons. And quickly propagate the plant if necessary.
The stem of a tomato with the leaves and inflorescence located on it is called a shoot. The growth of the stem is accompanied by its branching.
The stem of a tomato is round, 0.2-3m or longer, juicy; during growth, a cambium appears in the stem and it becomes rough, woody and lies down. The color of young stems is green with an anthocyanin tint in the upper growing part. Young stems can perform the function of photosynthesis. With the formation of many branches and under the weight of fruits, it bends and lies down. Some varieties are weakly branched (standard), others are strongly branched and in natural conditions have the shape of a plant with semi-raised branches - stepsons. In low-growing varieties, fruit clusters are often placed through one leaf, and at the ends of the branches one cluster follows the other, so the ripening of fruits in this type of tomato can be very smooth. In tall varieties, the inflorescences are located sparsely (every 2-4 leaves) and their fruit ripening is extended.
Depending on the nature of growth and branching, all tomato varieties are divided into two groups:
· Indeterminate (with unlimited growth);
· Determinate (with limited growth);
Indeterminate tomato varieties are characterized by strong
vegetative growth and high remontancy (constant resumption of growth and flowering), uniformity in yield and ease of plant formation into one stem, most varieties of this group are used in protected soil.
In determinate-type varieties, the main stem stops growing after the formation of three to five inflorescences. The average number of leaves between the inflorescences of determinate tomatoes is always less than three - there are two, one. Sometimes the inflorescence follows in a row, one after the other.
This group of varieties is distinguished by early ripening, uniform yield, and poor remontability. Such varieties are best grown in open ground, unheated film greenhouses and tunnels. (Gavrish S.F., 2003)
Tomato leaves are alternate, unevenly pinnately dissected, consisting of lobes, lobules and lobules, or only simple, large lobes. The surface of the leaves is corrugated to varying degrees.
On the stem, the leaves are arranged in a spiral, which changes its direction to the opposite for each sympodium.
Depending on the number and degree of dissection of the lobes, a tomato is divided into ordinary and coarsely lobed, or potato, leaves. But there are also transitional, intermediate forms. In standard varieties, ordinary and potato leaves are more compact, have a shortened petiole and a highly corrugated surface.
The leaf, unlike the stem and root, has a shorter life span. In a tomato leaf, the lifespan is on average 3-4 months. The aging and death of leaves in plants occurs gradually, starting with the cotyledons. (Gavrish S.F., Galkina S.N., 1990) The inflorescence of a tomato is an extra-axillary curl (tassel). There are simple two-sided inflorescences (when the axis of the inflorescence does not branch) and intermediate ones (single branched). There are forms in which the number of flowers in inflorescences reaches up to 200.
The first inflorescence begins to form on the plant during the opening of 2-3 true leaves, i.e. depending on the variety and external conditions, approximately on the 15th day after emergence. The yellow flowers are small (in currant and cherry forms) and medium in size (in cultivated forms).
The type of inflorescence largely depends on external conditions. A sharp change in temperature, light, and mineral nutrition leads to a deviation from the normal development of the inflorescence. When the night air temperature is lower during this period, the first inflorescence turns out to be more branched, with a large number of flowers. High night temperatures (22-24 °C) contribute to the formation of fewer flowers on a longer and thinner flowering axis than usual.
In a greenhouse in winter or early spring, when there is very little light, inflorescences either do not form at all or are underdeveloped. In summer, in the same honeycombs, with excess light and high soil and air humidity, the inflorescence can reach a length of up to 0.5 m. Very often, under such conditions and in the presence of a large amount of nitrogen in the soil, they “grow”, i.e. leaves and even shoots form on the inflorescence. (Gavrish S.F., 2003; Gavrish S.F., Galkina S.N., 1990)
The plant blooms gradually, from bottom to top. When plants are formed into one stem (removal of all lateral stepsons), indeterminate varieties bloom simultaneously with only three inflorescences, a maximum of four. Superindeterminate and determinate varieties, due to the more frequent arrangement of inflorescences (every one or two leaves), bloom more amicably (Gavrish S.F., 2003).
On the inflorescence, the flowers located closer to its base first open, and then gradually, depending on the variety and conditions, all the others open over the course of 5-15 days.
The tomato flower is bisexual, five-six-membered and consists of a calyx, corolla, stamens and pistil. The calyx is formed from sepals fused at the base. The corolla of a flower opens when its petals turn yellow. At the base, the petals grow together and form a short tube. The stamens are connected to each other by short hairs to form a stamen cone, inside of which there is a pistil with a stigma. (Gavrish S.F., Galkina S.N., 1990)
Tomato flowers are self-pollinating. But at high air humidity, pollen grains swell, stick together, and pollination does not occur. Often in tomatoes ( large-fruited varieties) there are fasciated (overgrown) flowers, from which multi-chambered, ribbed and often deformed fruits are subsequently formed (Gavrish S.F., 2003)
After fertilization of the ovules, the growth of the ovary begins. The ovary of a tomato is superior, with a different number of sockets. From flowering to ripening it takes 45-65 days.
Two to four flowers bloom at the same time. Each of them will remain open for an average of three days. Then the color fades and the petals fade. In dry, hot weather this period is reduced to two days, and in cloudy and cold weather it increases to five to seven days or more. (Gavrish S.F., 2003)
The tomato fruit is a fleshy, juicy berry. Small fruits (less than 50 g) - small-chambered (2-3 chambers), medium-sized (50-120 g) (medium-chambered 6-9 chambers). Large fruits (over 120 g) have 9 chambers or more. In some varieties there are fruits weighing 600-800 g and even up to 2000. The shape of the fruits varies from flat, round to elongated oval, from smooth to strongly ribbed. In color, red, pink, yellow of varying color intensity. Depending on the uniformity of color of green fruits, all tomato varieties are divided into two groups:
· With uniformly colored fruits;
· With fruits that have a green spot of varying intensity at the place of attachment of the stalk.
The biological stage of fruit maturity occurs under normal conditions on average 40-45 days after fruit set. At this stage, the seed embryo acquires its characteristic size and ability to germinate. In this case, the fruit reaches its maximum size, but still has a green color.
Full ripening of the fruit occurs, depending on the tomato variety and cultivation conditions, 5-15 days after the biological stage of maturity.
The taste of fruits is determined by the content of sugars, acids and their ratio. The larger the arrival solar radiation, the more dry substances in the fruits, the better their taste (Gavrish S.F., Galkina S.N., 1990)
Fruits that have reached brown, blanzhesky ripeness, as well as green ones, fully developed with mucous placentas in the seed chambers, ripen well indoors at a temperature of 16-25 ° C. For transportation to other areas, pink fruits are collected, and for long distances, brown fruits, since ripened fruits lose their marketable qualities during long-term transportation. Healthy green fruits can be stored for 1-2 months at a temperature of 4-8°C.
Tomatoes, by their geographical origin, belong to Mexico and the dry subtropics South America, where it grows as a perennial evergreen. This determines many biological characteristics of the crop: requirements for light, heat, and limited watering. Analyzing the properties and characteristics of modern varieties, it should be noted that their wide distribution in various geographical conditions has led to significant variability in the culture. Its great plasticity, ability to easily adapt to different levels of illumination, and photoperiodic adaptation were revealed.
Tomato is a long day plant. The reaction to day length manifests itself early - already in the phase of the first one to three true leaves. In the initial period after germination, they show a positive reaction to irradiation with short-wave blue-violet radiation; this also indicates their origin from southern latitudes (high light intensity with a predominance of short-wave blue-violet radiation).
For normal growth and development, tomatoes need illumination of at least 10 thousand lux. There are also varietal differences in culture in this regard. Flowering and fruiting begin at illumination of at least 4 thousand lux. Optimal illumination 17-23 thousand lux; in this case, the duration of the photoperiod should be within 12-16 hours.
In ontogenesis, there is a period when tomatoes are especially sensitive to a lack of light - the stage of formation of germ cells, critical in relation to this factor. Even a short-term decrease in illumination at this time leads to significant disruptions in generative processes and the subsequent shedding of physiologically underformed reproductive organs, and ultimately to crop losses.
Prolonged continuous lighting has a negative effect on tomatoes, leading to disorders - poor development leaf blade, its pale color due to the destruction of part of the chlorophyll, the appearance of spots, possibly even the death of the leaf, disruption of normal fruiting processes.
Light intensity, its spectral composition, daily cycles of alternation of light and darkness - all these parameters are extremely important for the normal functioning of tomato plants.
Temperature has a great influence on the plant, under the control of which all basic processes are to a greater or lesser extent. Adaptive mechanisms allow maintaining the normal level of vital activity of the body within certain temperature limits; significant deviations in one direction or another lead to disturbances, damage and even death of the plant. The effects of temperature and light are closely interrelated.
During the growing season, optimal temperatures for tomatoes vary. After emergence, it takes a little more low temperature, which is necessary to enhance the growth of the root system, accelerate the transition of the root system, accelerate the transition to autotrophic nutrition, and prevent plant debility. During the fruiting period, the temperature should be increased.
Significant temperature deviations from the optimal temperature for plants have, to one degree or another, a depressive effect on growth and reproductive processes. According to generalized literature data, at temperatures below 15°C, plants do not bloom, the formed buds at a temperature of about 12°C do not open and fall off, and at temperatures below 15 °C, growth stops. Growth processes are also disrupted at elevated temperatures. At a temperature of 30°C, growth slows down, and at 35°C and above, it stops completely. Above 32°-35°C, pollen becomes sterile and fertilization is impaired. Sudden sharp changes in temperature are also harmful to the plant.
Since tomatoes originated from dry subtropics, they need low air humidity and rare but abundant watering is more favorable for them, taking into account the level of insolation, physical properties soil, stage of plant ontogenesis. Excessive soil moisture by frequent watering increases air humidity and negatively affects the condition of tomatoes: young plants become very elongated. A significant increase in optimal air humidity impairs fruit formation and creates preconditions for the development of diseases and the appearance of pests.
Soil moisture should be different depending on the phase of plant development: 70-75% of the highest moisture capacity before fruit formation and 80-85% when they are filled.
Tomato can be grown on various soils, but it feels best on sandy and loamy soils, which have good moisture holding capacity and breathability. In protected ground, you can use the same soil, well-filled with organic and mineral fertilizers.
The best soil acidity (pH) is 6.0-6.5. Acidic soils must be limed, otherwise many nutrients, primarily phosphorus, will be in a form inaccessible to the plant. At the same time, at pH< 7 блокируется поступление в растение калия, магния и железа. (Гавриш С.Ф., 2003).
During the first period of growth (from germination to fruit set on the first inflorescence), tomato requires moderate nitrogen nutrition and increased phosphorus. From the beginning of watering the fruits, it is necessary to increase nitrogen nutrition, and during their ripening - potassium nutrition.
Plant nutrients are required in different quantities and ratios. The need for a particular element depends on the type of plant, the phase of its development, and growing conditions. But you need to know that it is impossible to compensate for the deficiency of one element by adding another in excess. (Gavrish S.F., 2003).
Tomato, like cucumber, is responsive to CO2 fertilization in greenhouses. It continues to increase yield when the CO2 concentration increases to 0.3%, but it is economically feasible to use a concentration of 0.1-0.2% (Strizhev A.N., Belik V.F., 1998; Bryzgalov V.A., 1995) .
A valuable quality of tomato fruits is their tendency to ripen after harvest. You can ripen blanc or formed green tomatoes. The best temperature for ripening is considered to be 20-25°C and relative humidity 80-85%. You can ripen in the dark, but in the light this process goes faster and the fruits acquire a more intense color (Bekseev Sh.G., 1989; Tarakanov G.N., 1984; Gavrish S.F., 2003; Bryzgalov V.A., 1995 ; Orekhov M.V., 2000)
Tomato plants in a greenhouse are mostly very powerful, sometimes gigantic. To obtain high productivity, a well-developed vegetative mass is necessary, but with its excessive development and intensive consumption of assimilants, their deficiency may occur during the formation of generative organs. Due to dense foliage, lighting conditions worsen, especially for the leaves of the lower tiers, and the intensity of photosynthesis decreases (Dachernig A.).
The ratio between the aerial part and the root system, due to the weak development of the latter and the intensive growth of the stem and leaves, is greater than that of open ground plants.
The specific conditions of the greenhouse also leave an imprint on the anatomical structure of the leaf.
The tomato is an autonomous plant that does not require special environmental conditions. It blooms in a timely manner when environmental conditions allow it. When the total daily accumulation of photosynthetically active radiation (PAR) remains constant, flowering occurs within a few days. It was also noted that as the temperature decreases, the number of leaves before flowers begin to appear decreases. The flowering of most inflorescences begins consistently (2 months after sowing), only 1-2 flower buds that are the last to form invariably fall off.
An increased supply of nitrogen stimulates reproductive development in high light conditions (pre-flowering phase of reproductive organ development). Conversely, when light is limited, excess nitrogen suppresses flower development and fruit formation.
Economic importance and the nutritional value tomatoes
Tomato culture, due to the high nutritional value of the fruit, occupies a leading place in vegetable growing in most countries of the world.
Tomato fruits are consumed raw in the form of salads, numerous seasonings (for meat, fish and vegetable dishes), salted, pickled, stuffed.
The value of fruits as a food product is determined by the carbohydrates, organic acids, mineral salts, aromatic substances and vitamins they contain (C, carotene, B1, B2PP, K, etc.)
Varieties common in Moldova contain 4.5 – 9.2% dry matter in fruits, 1.9 – 4.9 sugars, 0.05 – 0.26 starch, 0.18 – 0 fiber (with hemicelluloses), 42, pectin 0.12 – 0.33, nitrogenous substances – 0.55 – 1.65, organic acids – 0.30 – 0.85%, ascorbic acid – 12 – 36 mg%, carotene – 0.6 – 14 mg%, vitamin B 1 –80 mg.
The dry matter composition of tomato fruits contains the most carbohydrates (36 - 62%), which are represented mainly by soluble sugars among sugars - glucose and fructose. There is little sucrose in tomato fruits (0.1 - 0.5%). The glucose content is 1.5 - 2 times higher than fructose.
Pectins make up a small percentage of dry matter, but play a very important role in the formation of the structure and density of fresh fruits; the consistency of tomato processing products also depends on it. Most pectins are found in unripe fruits, and as the fruits ripen, their amount decreases.
The group of organic acids is dominated by citric and malic acids; it also contains small amounts of tartaric, succinic, oxalic and lactic acids.
The ash elements contain a lot of potassium (38.14%), sodium (17.03%), magnesium (8.63%), phosphorus ((9.14%), calcium (6.1%), sulfur (4. 78%), silicon (4.80%), chlorine (6.93%), iron (2.33%).
Tomato fruits contain a large group of vitamins (C, A, B1, B2, PP, etc.).
Biological features of tomatoes
Tomato is a herbaceous annual plant of the nightshade family. The stem and shoots at a young age are soft, juicy and fragile. As the stems grow, they spring and lie down. The plant has a lot of branches. The branching of tomato stems is sympodial, namely: the initial shoot ends its growth with the formation of the first inflorescence, in its place appears the next lateral shoot, which fuses with the leaf bearing it and grows upward with it. The first inflorescence is pushed to the side.
After the formation of 1-3 leaves (depending on the variety and growing conditions), a flower raceme is formed on the shoot of the first order, its growth stops and the stem continues with a side shoot of the second order, etc.
The stems are rough, densely covered with glandular hairs, and swollen at branching points. The leaves are alternate, once or twice pinnately dissected, unpaired, rough. The flowers are bisexual, collected in an inflorescence - a raceme with different numbers flowers in it. The calyx is sphenoid with 5-6 lobes. The corolla is sphenoletal, there are 5-6 or more stamens, the filaments are very short, the ovary is multilocular. The style is straight, the stigma has 2-3 or more lobes. The flowers are adapted to self-pollination, but cross-pollination by wind and insects can also occur. The fruit is a juicy berry with different colors (red, crimson, yellow, white).
Seeds are flattened, kidney-shaped. The root of young plants is rod-shaped, but then becomes thin and does not stand out among the rest. In addition to the main root, lateral roots appear. They grow almost horizontally.
On the lower part of the stem, after filling with moist soil, the plant is capable of forming adventitious roots. Their penetration depth depends on the density, moisture and aeration of the soil, as well as other growth factors (nutrients, temperature, etc.). Under good conditions, the roots penetrate the soil up to 1.0 - 1.5 m.
Zoned varieties of tomatoes and their characteristics
In the farms of Transnistria, Moldova, Ukraine, Russia and other CIS and foreign countries, 40 promising varieties of tomatoes have been zoned.
Breeders of the Transnistrian Research Institute Agriculture made a great contribution to the development of agricultural science and developed the following varieties that are used by collective farms and farmers.
Early maturing hybrids for film greenhouses in Transnistria and Moldova: Flamenco and Corona.
Flamenco is an early hybrid. Fruit ripening is 105–108 days after emergence. The plant is powerful, medium-leafed, height up to 1 m. The fruits are round. The color of the unripe fruit is green, the color of the ripe fruit is red. Weight – 90 – 120 grams. Fruit yield in film greenhouses is up to 13 kg / 1 m 2. recommended for unheated film greenhouses and in open ground.
Crown is an early hybrid. It differs from the FLAMENCO variety in that the fruits are flat-round and weighing 150 g. used for early production of tomatoes in film greenhouses and in open ground on the trellis.
Early ripening varieties: Lyana and Yuliana.
Lyana is a very early variety with rapid fruit ripening, the duration of the period from mass germination to the beginning of ripening when grown in seedlings is 87 - 93 days. The plant is highly leafy and medium branched. The height of the stem is 35 - 40 cm, the diameter of the bush is 40 cm. The fruits are round, smooth, bright red, weight - 80 grams.
Juliana is an early variety that ripens quickly. The duration of the period from the emergence of seedlings to the beginning of ripening when grown by seedlings is 102 - 104 days. The height of the main stem is 40 - 45 cm, the diameter of the bush is 35 - 40 cm. The fruits are bright red. Weight 70 – 80 grams. Designed for reusable cleaning and fresh consumption.
Large-fruited varieties: Perseus, Morning, Quiz, Torch, Potok.
Perseus is a mid-early variety: from germination to the beginning of fruit ripening 108 – 115 days. The plant is powerful, well leafy. The fruits are flat-round, large 130-180 grams, bright red. Productivity in seedling crops is from 80 to 100 tons/ha. Intended for fresh consumption of fruits, for canning, making paste and juice.
Morning is a mid-early variety: from sunrise to the beginning of fruit ripening 110 – 115 days. The fruits are round and smooth. The color of the unripe fruit is light green, the mature one is red. Fruit weight is 80 – 90 grams. Productivity 45 – 80 tons/ha. Intended for fresh consumption.
Victorina is a mid-early variety; in seedling culture, the fruits begin to ripen 112 - 120 days after emergence. The plant is medium leafy. The fruits are round and intensely red. Weight 150 -200 grams. Productivity 50 95 tons/ha. The taste is good. Can be grown in seedlings and without seedlings. Intended for fresh use and industrial processing.
Fakel is a mid-early variety: from germination to fruit ripening 115 – 127 days. The fruits are round, smooth, red. Weight 60 – 100 grams. Productivity 80 – 100 tons/ha. Designed for reusable cleaning, making paste and juice.
Potok is a mid-season variety: in seedling culture it begins to ripen 115–200 days after emergence. The color of the ripe fruit is intense red. The fruits are round and smooth. Weight 120 – 150 grams. The taste of the fruit is good. yield 60 – 70 tons / ha. It is characterized by increased field germination of seeds at low positive temperatures. Can be grown in seedlings and without seedlings.
Orange-fruited varieties: Luch, Glory of Moldova, Alex.
Luch is an early variety: the period from mass germination to ripening is 98 – 102 days. The fruits are elongated oval, smooth, orange in color. Weight 50 -80 grams. The taste is good, it is intended for canning, in order to obtain a dietary product for areas with increased radiation and as a prophylactic agent for cancer.
Slava Moldavii is a mid-early variety: from emergence to the beginning of ripening when grown in seedlings 109 -120 days, in non-seedling cultivation 95 - 100 days. Medium leafy plant. The height of the main stem is 40 -45 cm. The fruits are round and orange in color. Weight 75 – 80 grams. Productivity 50 – 60 tons/ha. Intended for baby and dietary food, for fresh consumption.
Alex is a mid-season variety: from mass germination to the beginning of ripening when grown in seedlings, 115–120 days. The fruits are elongated oval, smooth, orange in color. Fruit weight 70 grams. Productivity 40 – 60 tons / ha. Used for fresh consumption, industrial processing and production of high-quality preservatives with a high carotene content.
Long-fruited varieties: Impulse, Prizer, New Transnistria, Gusar, Credo, Reef, Dedication, Onyx, Maryushka, Cup of Moldova. Let us characterize some of them.
Impulse is an early variety: from germination to fruit ripening in seedlings 103 – 105 days. The shape of the fruit is ellipsoidal, the color is dark red. Weight 70 grams. Productivity 50 -70 tons / ha. It is used for one-time mechanized harvesting, used for seedlings and non-seedlings, for canning and fresh consumption.
Prizer is a mid-early variety: from germination to full ripening of fruits 112 -114 days. The fruits are elongated-oval. The color of the ripe fruit is red. Weight 60 grams. The taste is good. Productivity 60 -90 tons / ha. The variety is recommended to be grown in seedless culture and is suitable for combine harvesting. Designed for concentrated tomato products, pickling and fresh consumption.
A new product from Transnistria is a mid-season variety: from germination to harvest 120 – 125 days. The fruits are elongated-cylindrical in shape with weak ribbing, red in color. Weight 40 – 60 grams. In a seedling crop, the yield is 65 - 90 tons / ha, in a non-seedling crop - 50 - 60 tons / ha.
Hussar is a late variety: from sunrise to one-time harvesting 125 – 130 days. The fruits are cylindrical, smooth, the color of the ripe fruit is red. Weight 75 – 80 grams. Productivity 70 – 90 tons/ha. Designed for mechanized harvesting and canning.
Gloria is a mid-season variety: from germination to fruit ripening 115 - 120 days. The fruits are red, round-oval in shape. Weight 80 -120 grams. Productivity 5 – 8 kg/m2. recommended for fresh consumption and for the preparation of high-quality tomato products (tomato juice, paste, whole-fruit canning).
Varieties for protected soil: Orange, Syuzhet, Quartet, Decembrist, Pridnestrovsky.
Orange is an early hybrid: from germination to ripening in winter greenhouses the average is 120 days. The fruit is flat-round in shape. Weight 50 – 60 grams, slightly ribbed surface. The color of the unripe fruit is light green, the mature one is orange. Resistant to lack of light, heat and diseases. Productivity up to 24 kg/m2. Recommended for growing in winter-spring crop rotation in greenhouses, as well as for growing on windows.
Pridnestrovsky is a mid-early hybrid: the period from mass germination to fruit ripening is 130 days. The fruits are round and smooth. Weight 100 -1209 grams. The color of the ripe fruit is red. Designed for cultivation in winter and spring film greenhouses, the yield in winter greenhouses reaches 20 kg/m2, in spring film greenhouses - 10 kg/m2.
Tomato, as a native of subtropical countries, is a crop that requires heat and light. Tomatoes are considered a relatively drought-resistant crop, however, during the period of flowering and fruit set, the need for water is quite high. Tomato is less demanding on soil fertility than many other vegetable plants. However, if you create higher than optimal growing conditions for tomatoes, they will respond with a multiple increase in yield.
Temperature. Tomato seeds begin to germinate at a temperature of 10...12 o (northern varieties at 8...9°). The optimal temperature for germination is 20...25 °. Plant growth stops at 10°. At temperatures below 15° and above 35°, tomato plants do not bloom, and at 10°, growth stops, pollen does not ripen, and the ovaries fall off.
Seedlings and young tomato plants can withstand quite a significant decrease in temperature, down to 0...0.5°, germinating seeds before sprouts appear up to - 10°. At a temperature of -0.5°, flowers and fruits die, and at minus 1° the entire plant may die. Only some varieties can withstand frosts down to minus 3 o. Sharp temperature drops from 25° and prolonged cold spells retard the growth and development of plants and also cause flowers to fall off. The optimal temperature for the growth of adult tomato plants is 22...24° during the day, 16...18° at night.
Humidity. The tomato is an average moisture-demanding and relatively drought-resistant crop. However, it requires increased soil moisture (approximately 70...80%), but at the same time relatively low air humidity of about 60%.
During the fruiting period, air humidity is needed within 65...70%. Changes in soil moisture impair the growth of the root system and the flow of nutrients into the plant, leading to disease. Uneven supply of moisture leads to cracking of fruits and falling of flowers.
Particular care must be taken to provide plants with air. If there is a lack of air in the soil, the seeds germinate slowly, the roots stop growing, and the normal nutrition process is disrupted. This requirement obliges the vegetable grower to use soil with a good lumpy structure for growing tomatoes (especially seedlings).
With insufficient moisture, accelerated ripening of set fruits is observed with mass falling of new flowers and ovaries. A plant, experiencing stress, strives to reproduce seeds and gets rid of reproductive parts that compete in nutrient consumption.
If drought occurs during the fruit growth stage, this leads to the development of blossom end rot and almost complete loss of the crop. Equally, troubles arise with excessive moisture, which causes excessive growth of leaves to the detriment of fruiting. High air humidity makes it difficult to fertilize flowers and creates conditions for plant disease.
Light. Tomato is a light-demanding crop. The brighter and more intense the light, the faster the harvest is formed. With a lack of lighting, the assimilation process sharply decreases, plant growth is weakened, and development is delayed. Prolonged cloudy weather extends the period from flowering to fruit ripening by 10...15 days, worsening their taste and marketability. Most varieties of southern origin are short-day plants, while those of northern origin are day-neutral or long-day plants.
Soil and nutrition. However, the best results are obtained by tomato culture on well-warmed fertile soils, chernozems rich in organic matter and floodplains that are not flooded or early cleared of hollow water with a pH of about 6.0 (5.5...6.5). Good harvests Tomato production can also be obtained on sandy and loamy soils by applying the necessary fertilizers and maintaining the soil in a loose state.
Tomato responds well to both mineral and organic fertilizers. On cultivated soils, it can give a high yield when only mineral fertilizers are applied, and on low-fertility, low-humus soils, a combination of mineral and organic fertilizers is advisable. Among organic fertilizers, humus, manure (preferably in autumn), peat manure composts, slurry, and bird droppings are applied to tomatoes.
Of the mineral nutrition elements, tomato consumes more potassium and nitrogen. However, it is very responsive to phosphorus fertilizers, without which it is difficult to obtain a high yield and good quality fruits
Tomatoes take a lot of nutrients out of the soil. In the initial period of formation of the root system, the role of phosphorus is especially great. Therefore, at a young age, plants most need fertilizing with phosphorus fertilizers. Subsequently, when the process of fruit formation begins, phosphorus, together with potassium, helps accelerate flowering, fruit ripening and increase the plant’s resistance to disease.
Tomato consumes a lot of nitrogen to form a crop, and the need for it increases as leaves and stems grow and reaches a maximum during flowering and fruit formation. Tall varieties use comparatively more nitrogen than short varieties. When providing plants with nitrogen, we must not forget that abundant nitrogen nutrition during leaf growth delays fruiting, contributes to the pampering of plants and their damage by diseases.
The need for potassium in tomatoes increases gradually (from the beginning of stem formation) and reaches a maximum during the period of increased fruit growth.
Lack of calcium leads to plant disease crown rot fruits, in addition, the top of the stem dies off, the root system develops poorly. The plants' need for calcium should be covered by liming the soil (until a slightly acidic reaction).
In soils poor in organic matter, tomatoes may lack magnesium.
