Frost resistant citrus. Citrus hybrids: varieties and growing at home

The key to successful cultivation of citrus plants is not only the creation favorable conditions in the apartment, but also care that meets their needs. However, the first difficulty that one has to face is the choice of a green friend. Alas, it often fails. On the counter, the plant looks like a real beauty, and a week after the purchase, for some reason, it turns into a pitiful scumbag.

Plants strewn with bright fruits are usually sold in November-December, when they mostly bear fruit. So, they have, as businessmen say, the best marketable condition and, accordingly, the highest price, and the maximum demand. That is why, by the end of the year, seductive fruit-bearing citrus fruits, similar to Christmas trees with toy decorations, fill both markets and shops. What is the real perspective, not even prosperity, but at least just their survival on the windowsill? Alas, it is minimal!

All greenhouse sissies are capricious. Any fruit-bearing plants are conservative and require the same conditions that they are used to. What were they? Fruiting tangerines, kinkans, oranges and lemons, Russian intermediary firms buy most often in Holland. There they, in turn, come from greenhouses in Germany, Denmark and the countries of Southern Europe. There, for their growth and quick entry into fruiting, climatic conditions not different from the subtropics. That is, in these greenhouses, lighting and air humidity are brought to the ideal!

Inexperienced lovers are simply not able to repeat the same on their windowsills. Therefore, most likely, a live “purchase-picture” is doomed. By the way, in Holland itself, it is customary to buy fruit-bearing plants in pots for Christmas and other winter holidays only as disposable ones, that is, they keep them at home like a bouquet of flowers - until they wither, then they throw them away.

It is clear that our Russian buyer would like to count on much more long life of your acquisition. However, only those who are able to provide the hothouse handsome man with similar conditions of detention have real chances for this. But, we repeat, it is very difficult to do this.

Do not buy open-rooted citrus fruits.

Even when the roots are packaged in bags. Such plants, as a rule, are sold in the markets and at any city flea market (in Moscow and near metro stations). And they are brought from the Black Sea coast, where they hastily dig out of the ground, and then shake them in large, tightly stuffed bags for a long time in transport. Immediately before the sale, they are given a more or less marketable appearance.

An experienced citrus grower will bypass such a gift from Sochi or Sukhumi. With rare exceptions, such a plant will die sooner or later. And there are at least two reasons for this. Firstly, the roots of any citrus fruits cannot stand either rough handling or any long stay out of the soil, and a bag and a bag do not save from this. Secondly, even if Sochi-Sukhumi citrus fruits were grown and sold in pots, they would still not be suitable for our window sills.

The fact is that in the Black Sea subtropics citrus plants in January-February, they are grafted onto the most winter-hardy, but deciduous species - trifoliata.

In winter, it is in a state of deep biological dormancy, which means that it cannot tolerate heat above 10 ° C. In a dream, the roots do not function and do not absorb water, and the leaves in a hot room evaporate it intensively. With such a discrepancy, death quickly ensues. Therefore, a citrus plant grafted on trifoliate, if it can be grown here, is only on cool balconies and loggias or in winter gardens.

Much easier to tame youngsters. It has long been known that any living organism, not excluding plants, gets used to new conditions of detention much easier and faster, including not the best ones, from an early age. For citrus fruits, this is the age when they are only a few months old, that is, long before fruiting. It is unprofitable for businessmen who supply foreign supplies to sell such plants. But citrus seedlings have finally been grown by several of our greenhouse complexes, small private nurseries, and just experienced amateurs.

However, even if we assume that only young varietal citrus plants are displayed on the counter, which are quite adapted to home conditions, then on an ordinary windowsill, under the same conditions, different species will behave far from the same way. Some will be capricious, others will quickly adapt. According to the rating of citrus fruits, calamondins are the most unpretentious in terms of endurance, followed by tangerines, oranges, citrons, lemons, grapefruits, and kincanas close the list. There is a scatter even within some species, that is, a variety from a variety differs very significantly. You will agree with this when you become familiar with the characteristics of different types and varieties of citrus plants.

Out of order of endurance rating and we will tell about them in more detail, not only because among all other types of citrus fruits we have them the most popular. And also because there are so many varieties of lemon sold that it is easy for an inexperienced lover to get confused. We will help you make the right choice.

Meyer. The main advantage of this most purchased variety is short stature. Accordingly, the leaves and fruits are medium-sized. The taste is sweet and sour. It enters fruiting in the second year of life, and sometimes at the age of one. And it blooms and bears fruit very plentifully. There are also disadvantages. Not infrequently, it throws out only buds, forgetting about the leaves, and then the plant simply has nothing to absorb the light with. To save him, you need to remove most of the buds. Another disadvantage is a very painful reaction to the lack of light during the winter months.

Panderose. The tree is medium-sized, with a spreading crown, short thick shoots. The fruits are large. It enters fruiting in the 2nd year of life. It blooms profusely, often even excessively. Therefore, in order to avoid depletion of the plant, most of the buds have to be removed again. It grows well on any windows without additional lighting. Therefore, it is considered one of the most unpretentious varieties.

Novogruzinsky. The fruits of this variety look very elegant: bright golden, elongated oval shape, with a pointed tip. Aromatic, fruitful. However, with two drawbacks. Firstly, it bears fruit relatively late - only in the 4-5th year of life. And secondly, it is distinguished by tallness, large needles. Therefore, it is more suitable not for home windows, but for offices where there are large bright rooms.

Kursk. High-yielding, bears fruit in the 3rd year of life. It is quite unpretentious, although it loses a lot of foliage in winter with insufficient lighting. The main disadvantage is tall stature, so a strong shortening of the branches is required annually.

Pavlovsky. The result of almost a century and a half of folk selection, the Variety is rightfully considered unsurpassed in the ability of plants to adapt to room conditions, seedlings can adapt to almost any light and temperature. It blooms and bears fruit at least twice, and even 3-4 times a year. Plants are medium-sized and practically do not require pruning and crown formation.

Not everyone knows that this seemingly exotic culture surpasses many varieties of lemons with its unpretentiousness. Indeed, with sufficient light, you can grow fruits that are not inferior to those of the south: just as sweet, large and even with more tender pulp! Many of them are able to develop well and bear fruit even on those windows that face the north side, less than other citrus fruits suffer from dry air in winter.

Unshiu broadleaf. The most common variety that moved to the window from the Black Sea subtropics. The maximum height of an adult tree is 1.5 m, it bears fruit from 3 years.

Kowano-Wase, Miagawa-Wase. Dwarf varieties of tangerines, their height on the windowsill rarely exceeds 50 cm. They are less common, but more convenient for home conditions. They bear fruit in the 1st-2nd year of life.

On the windowsill, they also feel quite tolerable. The trees look very decorative: a slender crown and dark green, dense foliage. Unlike varieties grown from seeds, they are usually taller, therefore they require either regular pruning or maintenance in spacious rooms.

Gamlin, Smoothskin. One of the most convenient varieties for home use. They have a compact crown, height up to 1 m, tasty and early ripening fruits. They start fruiting at the 3-4th year.

A rare species of citrus. With their crown, leaves, as well as the oblong shape, color and taste of fruits, citrons almost do not differ from lemons. But they are much larger and have a bumpy, thick, grapefruit-like peel.

Pavlovsky. Most famous variety citron. Like the lemon of the same name, it comes from Pavlov. By the way, for the bumpy surface there it is often called shishkan. Differs in beautiful oblong large leaves. Compared to lemon, the tree is more decorative.

One of the largest citrus fruits. Plants are tall, so on the window they need to be severely cut annually. It is better to grow indoors, where there are large windows and wide window sills or well-lit hallways.

Duncan, Seedless March, Jubilee. This is the best varieties grapefruits, come into fruiting at the 3-4th year of life.

Close relatives of citrus fruits. In terms of the number of potted fruit-bearing trees imported from Holland to our country, kinkans are in the lead, since they appearance impeccable and very seductive. Just what you need as a gift for the holiday: squat trees with dense foliage, literally strewn with golden fruits. They are eaten with the skin on. They are very original in taste and give a refreshing, prickly effect, almost like champagne. Sometimes kinkans go on sale under the name kumquats. They grow well and bear fruit only on sufficiently lit windows. With a lack of light, leaves lose much faster than they renew and eventually dry out.

Most often, two varieties of kinkan are sold: with fully rounded fruits (thick-leaved Meiva) and elongated oval (pearl Nagami). They begin to bear fruit in the 3rd year of life.

These are hybrids of kinkan and mandarin. Abroad, due to their unpretentiousness, they are more often grown on a windowsill or balcony than other citrus fruits. And in the summer they put them outside, where they decorate the place in front of the house and open verandas.

The golden fruits from this tree resemble tangerines, but are rounder and smaller (2-4 cm), with a thinner peel. The leaves are smaller than those of other citrus fruits, dark, leathery, oval-pointed. By the way, compared to lemon and orange, calamondin bears fruit more abundantly. Even with dry air and lack of light. A dense leafiness in combination with beautiful crown, lush bloom makes calamondin a real window sill decoration in any home.

Almost all commercially available varieties come into fruition in the 3-4th year, and they are all unpretentious. True, the most original calamondin - variegated, with white edging on the leaves - is rather capricious and is suitable only for windows with good lighting.

Admiral Apraksin brought the first two hundred small fruit-bearing citrus trees in pots to Russia in 1708 at the direction of Peter the Great. At first, privileged persons grew them in their greenhouses and greenhouses. The exception is still the city of Pavlovo Nizhny Novgorod region, where window citrus growing has become a hobby of almost all local residents (see "Science and Life" No. ). Now, 300 years later, many domestic and foreign companies are engaged in the cultivation of exotic seedlings, and home citrus growing attracts more and more plant lovers. But only those who will rely on the experience of previous generations of citrus growers can count on luck.

Science and life // Illustrations

The main advantage of the Meyer lemon tree is short stature. Accordingly, the leaves and fruits are medium-sized, with a thin peel. This variety blooms and bears fruit very abundantly.

With sufficient lighting on the windowsill, you can grow tangerine fruits that are not inferior to the southern ones. They are just as sweet, large and even have more tender flesh. In the photo: tangerines dwarf variety Miagawa-Wase. Plant height rarely exceeds 50 cm.

The most common variety of mandarin, Unshiu broad-leaved, bears fruit from the age of three. Fruits without seeds, with a smooth thin skin.

One of the most unpretentious varieties lemon - Panderose. The tree is medium-sized, with a spreading crown. The fruits are large.

Fruits of the Novogruzinsky lemon variety are very fragrant - they are elongated-oval in shape, with a pointed tip.

Citrus fruits, even on the same branch, do not ripen at the same time.

In the room, oranges feel quite tolerable. The trees look very decorative: a slender crown, dark green dense foliage and rather bright fruits.

Grapefruit is one of the largest citrus fruits. Plants are tall, so when planted in a window, they need to be severely pruned annually.

Since the 18th century, myrtle-leaved orange, or sour orange, has been grown in Russia.

Citrus seedlings with a closed root system.

Formation of the crown of vigorous varieties of orange, grapefruit, lemon or mandarin.

With a lack of nitrogen, the leaves turn yellow, especially the lower ones and at the base of the shoots.

With poor nutrition, the dark green leaves of any citrus fruits become variegated.

Citrus buds appear at any time of the year, but most of them are in February-April and September-October.

Science and life // Illustrations

Science and life // Illustrations

Science and life // Illustrations

Science and life // Illustrations

I warn you in advance: not everyone should even try to grow lemons and other citrus fruits in an apartment. Home citrus growing- the destiny of passionate, dreamy and at the same time thoughtful, serious people who are capable of years, sparing no effort and time, to learn the numerous "secrets" of this difficult occupation, step by step comprehending its wisdom.

And all for what? In any case, not for the sake of the "real" harvest. And it's not even about satisfying one's own ambitions, but rather about something completely different - a kind of "sculpting" with my own hands the miracle of nature itself - the lemon country on a tiny windowsill.

This is not an exaggeration. Indeed, for any northerner, it is the evergreen tree of an orange or lemon, tirelessly blooming, with golden fruits - a "living" symbol southern countries with the eternal summer, where there is no gray-lead low-falling sky, short daylight hours and other discomfort that daily affects our mood and well-being.

The man-made oasis seems to help, together with the plants, to move into the fairy tale of the subtropics.

But here is another paradox: not a single company that imports citrus fruits even attaches a short growing instruction to them. As a result, the life expectancy of acquired seedlings, sometimes expensive, is reduced to a few weeks, and luxurious southerners turn into miserable scumbags.

AT flower shops citrus fruits are usually sold in the late autumn and winter months, when all their types and varieties look equally festive, especially since they are grown almost in ideal conditions greenhouses and greenhouses under the supervision of specialists.

Sometimes it doesn’t even occur to buyers that a seedling bought for a lot of money in an ordinary apartment will have to experience, without exaggeration, shock and stress. Whether this whole plant will survive depends not only on our ability to create it the necessary conditions, but also on the life potential of a particular plant.

Forty years of personal experience in growing such sissies and information from amateurs that I receive after the publication of my books about these plants led to the conclusion that different species and varieties in the same room conditions do not behave at all in the same way: some die immediately, others get sick , others more or less adapt to life in any apartment.

Over time, I have compiled a kind of "ranking" of different types of citrus fruits in terms of hardiness (from high to low). And what is curious: practically this "rating" coincided with what was published more than 100 years ago by Professor N. N. Shavrov in the book "Tub and Hothouse Culture". So, the most unpretentious are the Pomeranians (bigaradia) and Calamandins, and the "fastidious" and "capricious" are Kinkans. Between them, in decreasing degree of endurance, are tangerines, oranges, citrons, lemons, grapefruits.

From abroad, we mainly import kinkans, tangerines, oranges; their presentation is impeccable, but, as a rule, the type of plant is not indicated. Lemons different ages- mostly Russian, from domestic greenhouse farms.

SELECTION OF VARIETIES

The most popular citrus fruits are lemons. Although this species occupies the place of "middlings" in the "rating", the existing varieties differ from each other. In terms of hardiness, I arrange them in the following sequence: Pavlovsky, Panderoza, Kursky, Meyer, Novogruzinsky, then all the rest (more than 100 varieties are known in total).

Pavlovsky. The result of almost a century and a half of folk selection (in the 60s of the XIX century, this lemon was brought from the Mediterranean coast of Turkey). Seedlings of Pavlovsky lemon easily adapt to room conditions. It blooms at least twice, and even three or four times a year. Plants are low- and medium-sized (up to 1 m), practically do not require pruning and crown formation. They begin to bear fruit in the third year. With good care, they give 10-30 rather large (up to 200 g) fruits from a tree.

Panderose. It grows well on any windows without additional lighting. Therefore, it is considered one of the most unpretentious varieties. The tree is low- and medium-sized, less than 1 m, with a spreading crown, short, thick shoots. The fruits are large (up to 50-100 g). It blooms profusely, therefore, in order to avoid depletion of the plant, most of the buds have to be removed. It enters fruiting in the second year of life. The yield is high, up to 10 lemons per tree, but the fruits have their drawbacks: they are thick-skinned, not acidic enough and a little dry.

Kursk. Bred in Kursk by amateur citrus grower A. A. Fomenko more than half a century ago. Unpretentious, although with insufficient lighting in winter it loses a lot of leaves. Fruits in the third year of life. On a glazed balcony, it gives more than 30 high-quality fruits from a tree. The main disadvantage of the variety is its tall stature, therefore, a strong shortening of the branches is required annually.

Novogruzinsky. Very elegant bright golden fruits of this variety. However, it also has two drawbacks. Firstly, relatively late fruiting - only in the fourth or fifth year of life. And secondly, tallness (up to 1.5 m and above) and large needles.

Productivity - up to 20-30 fruits per plant.

Meyer. The main advantage of this variety is short stature (0.5-1 m). It enters fruiting in the second year of life, and sometimes even earlier. It blooms and bears fruit very abundantly, the fruits are medium-sized, sweet and sour. This variety also has disadvantages. Often a plant throws out only buds, forgetting about the leaves, and then it simply has nothing to absorb the light with. To save the tree, you have to remove most of the buds. Another disadvantage is the painful reaction of the plant to the lack of light during the winter months.

The Meyer variety feels much better in our apartments when grafted onto home-grown citrus seedlings. As a result, the trees develop well and bear fruit abundantly: up to 20 fruits from each. The fruits are thin-skinned, juicy and less acidic than other varieties.

As for other types of citrus fruits, tangerines and citrons are more elegant than others. Mandarin trees are strewn with brightly colored, fragrant, sweet fruits. Citrons are distinguished by dark lush foliage and beautiful tuberous yellow fruits.

It is convenient to grow tangerines in small windows, since many of their varieties, especially dwarf ones, are rarely more than a meter high. Citrons after 10 years of growth are slightly higher.

Grapefruits are less suitable for window sills - because of their tallness: they often reach 1.5 m and above. However, they can be successfully grown in spacious areas.

Calamandins and oranges are very decorative, do not take up much space and are unpretentious. However, they have fruits of mediocre taste.

Much tastier than kinkans (their other name is kumquats), their fruits are eaten together with a piercingly fragrant skin. Kinkan trees are rather undersized, but capricious and require growing conditions close to ideal, which is easier to create on the balcony and in the loggia.

Very impressive fruit-bearing trees! But I do not advise you to be tempted by such plants when buying: they rarely get used to room conditions, often get sick and die. It is much more practical to buy citrus "youngsters", they adapt much easier and faster to life on the windowsill.

OUR WINDOWSILL IS NOT SUBTROPIC, BUT…

If you purchased and placed a citrus tree on the window, try to create conditions for it that at least remotely resembled the usual natural element - the subtropics. And initially room conditions, to put it mildly, are strikingly different from them.

In the homeland of citrus South-East Asia and the countries of the Mediterranean - a lot of light (daylight is equal to night, that is, 12 hours), high humidity (up to 95% on average) and favorable temperatures: from spring to autumn it is hot, and cool in winter (5-10 ° C heat).

Of the three listed factors more or less achievable in the room, oddly enough, only the last. The indicators of the microclimate of our window sill remotely resemble ... India and Italy, although, as a rule, in the winter months in our apartment it is warmer than it should be, and in the summer it is a little cooler.

But the other two conditions for the life of these sissies are very difficult to provide.

In December-January, at the latitude of Moscow, no more than 3-5 fine sunny days are usually given, and the duration of daily lighting drops by the end of the year to 7 hours instead of the required 12. Moreover, due to frequent cloudiness, a dim beam of light is simply not able to start the "motor "photosynthesis. And from November to mid-March, citruses are doomed to many months of hard to endure fasting.

After all, the main nutrition that is required every minute is not contained at all in certain fertilizers, but in the surrounding air - this is carbon dioxide, which turns into leaves into organic compounds only under the influence of a powerful light source - the sun!

Fasting is tripled due to low air humidity (25% instead of 95%). And as a result of this, the entrance "gates" - stomata for carbon dioxide - slam shut on the leaves, saving the life-giving moisture of the tissues from drying out.

It is clear that in order to save the tree, it is important to adjust two indicators of the habitat, namely: every day in autumn and winter, extend the lighting up to 12 hours due to bright lamps and in various ingenious ways to increase the humidity of the air to at least 50-60% (which, by the way, is important and to improve our well-being!).

Both goals are easily achievable, and in several ways. Ordinary household incandescent bulbs are categorically not suitable as an artificial "sun" (the wrong spectrum of light and too much heat). But fluorescent fluorescent lamps of daylight suspended directly above the crown of plants (ideally, two lamps of 80 watts each) are quite suitable, and even more effective. sodium lamps high pressure with a mirror reflector, produced by domestic manufacturers (one lamp with a power of 70 watts is enough).

As for increasing the humidity of the air, for this, saucers filled with water are usually placed on the windowsill, and plants are often sprayed from a spray bottle. All this helps, but not much. Much better to hang on the battery central heating a large wet towel, substituting a wide basin below on the floor. And even more effectively humidify the air in the room electric humidifiers different systems that are sold in stores.

FIRST CHALLENGES

The best place for citrus fruits is the brightest window sill, and even better - a double-glazed and insulated loggia. Immediately after the acquisition, the tree is transplanted (more precisely, "transferred" with the preservation of the former earthen coma) into a new pot, more conveniently - into a plastic one, with a diameter and height of 4-7 cm more than before. Do this very carefully, trying not to damage any of the roots. Be sure to arrange drainage at the bottom of the tank in the form of a two-centimeter layer of fine expanded clay, or better - swamp moss-sphagnum; the land mixture is made up of equal parts of leafy soil (completely rotted leaves collected under old maples and lindens), sod (it is obtained by simply shaking off earthen layers cut in a meadow or along the banks of a river, lake, pond) and compost sifted through a metal mesh with cells of 1 cm. The so-called special earthen mixtures "Lemon", "Orange", "For citrus" are least suitable for citrus fruits, since they consist exclusively of peat with the addition of mineral fertilizers. Watering trees in winter time usually every other day with boiled, settled water (at least 50-60% of potassium and magnesium salts are deposited in such water, which alkalize the soil), and ideally - with water passed through a household filter.

FEEDING AND PEST PROTECTION

In the future, citrus fruits require an annual transplant into a loose fertile soil and frequent (every decade) fertilizing irrigation from late February to August. You can limit yourself to top dressing with a weak aqueous solution (1:10) of fermented nettle, dandelion, comfrey and other weeds; they are insisted for a week in glass jar or a closed plastic bucket in a ratio of 1:1. As a rule, such dressings are combined with completely soluble complex mineral fertilizers- Sudarushka, Semitsvetik, Kemira-lux.

Much more worries and troubles are the troubles associated with the health of domestic citrus fruits, since they are a favorite delicacy for many pests. Attracts to them, like a magnet, aphids, whiteflies, spider mites and false shields (the latter are especially dangerous and difficult to eradicate).

Pest attack is one of the main reasons for the death of citrus fruits. The most effective means of protection in emergency cases are Aktara and Aktellik preparations. I advise you not to spray the plants, but to completely immerse their crown in a container with an insecticide solution. The biological drug Fitovern is also suitable (2 tsp per 1 liter of water), but this drug does not work at a temperature of +17 ° C and below. And here the best prevention- regular (every two to three months) treatment with the drug New FAS of high concentration (3-4 tablets per bucket of water).

So, the key to the successful cultivation of citrus plants is the creation of favorable conditions in the apartment, and care that meets their needs, and the ability to defeat insect pests. Only then will citrus trees bring you joy.

Detailed description of the illustration

Formation of the crown of vigorous varieties of orange, grapefruit, lemon or mandarin. Citrus fruits are pruned in February. On young seedlings, the top of the only growing shoot is shortened in order to quickly cause its branching, the appearance of branches of the 1st order. They are also pruned to get shoots of the 2nd order. This operation is repeated until fruit-bearing branches of the 4-5th order grow. In the future, pinching stronger branches, cause the growth of weak shoots, thereby forming a lush and beautiful crown. In the figure: a - pinching a branch of the 0th order; b - pinching branches of the 1st order; c - pinching branches of the 2nd-4th order.
Citrus buds appear at any time of the year, but most of them are in February-April and September-October. For more than a month, they develop, increasing in size. When opening at least one bud, a delicate aroma, somewhat reminiscent of the smell of jasmine, fills the whole house. As a rule, each flower has five dense petals, bright yellow fluffy stamens and a pistil towering above them with a stigma at the end. The flowers of many citrus fruits are self-pollinating, but the desired sweetish aroma attracts bees that fly into the apartment through the window.

Breeders from the Sochi Federal State Budgetary Scientific Institution "All-Russian Research Institute of Floriculture and Subtropical Crops" are currently working on the creation of large and frost-resistant lemons and tangerines. If the development is successful, farmers will be able to start producing citrus fruits on plantations in the Krasnodar Territory.

To do this, biotechnologists cross plants with large fruits and plants resistant to cold. Frost-resistant hybrids scientists plan to propagate using micrografting. A certain optimism is given to our farmers by cooperation with a large American institute USDA (United States Department of Agriculture - National Institute of Food and Agriculture). Sochi residents expect to receive rare and valuable citrus genotypes from colleagues from the USA for cultivation own brand, perhaps, together with the Americans, they will also conduct research on varieties.

Technology

For the ripening of mandarin and lemon fruits, conditions such as warm temperature and sunlight. If the temperature remains below +18 degrees Celsius for a long time, then the fruits simply do not ripen. To restore all citrus fruits after flowering fruit trees it is necessary up to six months, during which night temperatures should not fall below 13-16 degrees.

Therefore, regions with a favorable climate for growing, for example, tangerines are located in China, India, South Korea, USA (Florida), Spain, France, Morocco, Egypt, Algeria and Turkey. In the territory former USSR the northernmost areas of their cultivation are Sochi and Abkhazia.

- Our varieties, for example, Sochi Mandarin or Novogruzinsky Lemon, are adapted to extreme conditions region: the city of Sochi is the northernmost citrus growing zone in the world. As a rule, they like warmer regions. Most types of citrus fruits - lemon, grapefruit, orange - love warmer regions. Other species, such as mandarin-satsuma, and rarer relatives can grow in Sochi even without shelter. Thus, the Black Sea coast of the Western Caucasus is a border zone for growing citrus fruits, which creates optimal conditions for breeding for frost resistance. The development of methods for in vitro cultivation (in vitro) will speed up the breeding process and preserve the collection of valuable species and varieties of citrus fruits,- says Lidia Samarina, employee of the All-Russian Research Institute of Floriculture and Subtropical Crops, co-author of the development.

In the case of lemon, the micrografting method involves the spring selection of plants from the greenhouse. Specialists take buds from young shoots, sterilize and plant in a nutrient medium. Seeds are placed separately in the same soil: they begin to germinate, and after three weeks seedlings are obtained, ready for grafting.

Next, the top of the seedling is cut off, and a kidney 1–2 mm in size is placed in place of the cut. The bud grows together with the seedling - this is how a micrografted plant is obtained. This method, according to Samarina, allows to increase the multiplication factor by 1.6 times and the survival rate of micrografting by 6.6-35.1% compared with similar work in this area.

- The in vitro method is universal. For example, it makes it possible to obtain under artificial conditions such "chimeras" as the thornless blackberry. You can also focus on genetic engineering - genetically modified organisms(GMO), for example, artificial seeds, - reported n and the Department of Fruit Growing, Viticulture and Winemaking of the Moscow Agricultural Academy named after. Timiryazev.

Culture in vitro in Russia was developed after the Great Patriotic War. The founder of the trend in the USSR is considered to be Raisa Butenko, who in 1964 published the book "Culture of Cells and Tissues". In Soviet times, the research institutes had their own industrial plantations - about 80 hectares in Sochi.

At that time, the citrus harvest was 400 centners per hectare. After the collapse of the USSR, the squares were reduced, and the city was built up. For almost 120 years of history withOchinsk Research Institute was able to develop many new varieties of citrus fruits. ToIn addition, the institute's collection includes about 130 genotypes. But this is not much, considering that there are more than 900 of them in the US collection. In addition to citrus fruits, the institute is engaged in persimmon, feijoa, hazelnuts, kiwi, and tea breeding.

"In order for us to reach the US level and ensure import substitution, our institute lacks young specialists; if we had a hotel for graduate students and young scientists, we could attract valuable personnel and solve the tasks more effectively."

Cultivation of lemon in vitro will help Sochi residents to preserve promising genotypes in their collection of citrus crops. First of all, these are plants that are resistant to harsh Russian winters, various diseases, etc. Of course, varieties with large and sweet fruits, with a high content of vitamins, are also considered valuable genotypes. According to these criteria, breeders select promising genotypes that are stable in a particular growing area.

- The advantage of the method of cultivation of lemon in vitro developed by us is that it allows preserving and multiplying genotypes with a high degree of reliability and genetic stability due to the modification of the micrografting technique and the composition of the nutrient medium. If we propagate plants in other ways, then mutations can occur, that is, plants can give genetic abnormalities. If we plant seeds, we will not reproduce the variety with its valuable properties at all. And if we vaccinate, then with 100% probability we will get exactly the variety that we took from the greenhouse, - says Lidia Samarina.

Obstacles

Raisa Kulyan, Head of the Breeding Laboratory of the Department of Subtropical and Southern Fruit Crops of the Research Institute, talks about three problems of modern domestic citrus growing that do not allow Russia to replace supplies from Turkey and other countries:

- They used to collect much more than they do now. Each farm and each collective farm had its own area for citrus fruits. Today, there remains a spot laying of gardens on the coastal territory. These are Abkhazia, Adler and a small piece in Sochi. But nevertheless, the yield is high, 200 centners per hectare, - says Kulyan. - The taste of foreign citrus fruits is completely different. For example, a lemon can hang on a tree for two years. It turned yellow, but they forgot to take it off, it turned green, and then again in the fall, a year later, it turned yellow. It was taken down and released. Naturally, there will be a completely different taste. Lemon is the only fruit crop that does not shed its fruits, they can hang on the tree indefinitely. Therefore, when the barrel of a lemon has turned yellow, you need to immediately remove it, it "comes to a lying position."

citrus economy

Directors news agency fruitnews Irina Koziy believes that a this moment it is impossible to seriously consider import substitution of citrus fruits in Russia. Firstly, the total production of citrus fruits in Russia is about 20 tons per year, respectively, there is no question of any commercial production volumes and cannot be. Secondly, in no country in the world in similar climatic zones citrus fruits do not grow commercially.

- It is possible, of course, heroically overcoming all difficulties, to grow citrus fruits in specially equipped greenhouses, but the cost of such greenhouse fruits will be several orders of magnitude higher than the cost of imported analogues. In the Russian climate, it is possible to effectively develop the production of apples and certain types of berries from fruits, as well as to grow certain varieties of pears and grapes. In these categories, both the production volumes and the success of domestic selection still leave much to be desired, but there is some progress, and I really hope that the efforts of producers and breeders will be applied to the development of these categories and we will see the results in the medium term, - says Koziy. - And the theme of frost-resistant citrus fruits most of all resembles an unforgettable reprise from the film "Garage" about breeding frost-resistant macaques to collect cedar cones in the Siberian taiga. In my opinion, the benefit from import substitution of citrus fruits will be approximately the same as that of the hero of the film.

According to FruitNews, the growth trend of citrus imports in the domestic market was traced until 2013. Now there is a drop in both demand and supply due to a decrease in income and purchasing power of the population. The total production of all citrus fruits in Russia in 2015 amounted to 20 tons, in 2014 - 24.5 tons, in 2013 - 15.5 tons.

The volume of imports of tangerines in 2014 amounted to about 847 thousand tons, and in 2015 - about 777 thousand tons.The volume of imports of lemons in 2014 is about 209 thousand tons, and in 2015 - about 201 thousand tons. According to the Ministry Agriculture USA, Russia is the world leader in terms of imports of tangerines, and in terms of imports of lemons it is second only to America and the EU.

Breeders see the spread of their method in several directions. If they can increase the frost resistance of their varieties by at least two degrees, lemons and tangerines will go to the mountains. If not, they will go to Abkhazia.

- Sochi is a mountainous territory, the climate is characterized by vertical zonality. High-rise buildings have not yet been set up in the mountains, there are many areas that can be used for farmland. There are special agrotechnical horticultural practices for mountainous areas; up to an altitude of 600–900 m above sea level, it is quite possible to plant plantations. The second direction of application of developments on citrus fruits is Abkhazia, our institute has long been exchanging collection varieties of citrus fruits with the Abkhaz Research Institute of Agriculture of the Academy of Sciences of the Republic of Abkhazia. They have production area. And we have scientific developments, but there is little space for industrial plantings, says Samarina.

So it is customary to call the fruits of citrus fruits - oranges, lemons and tangerines. They are called golden for the color of the fruits: sometimes orange, sometimes yellowish, and figuratively, for high taste qualities and medicinal value.

The combination of pleasant acidity with sweetness, wonderful aroma, pleasant refreshing taste, a large number of valuable vitamins put citrus fruits in the first place.

Any citrus tree is decorative, and flowering has a delicate and strong smell. All citrus plants love warm climates. Of these, lemon, orange, tangerine, grapefruit are more widely known, and less so are kinkans, citrons and others.

Originating in warm countries, although not tropical, citrus fruits have a different growth pattern than deciduous and some other evergreens. At home, lemon gives rise to branches five or six times a year, orange and tangerine also give several growths. Trees all year round grow, reach large sizes, bloom profusely and bear fruit.

In our country, citrus plants fell into conditions that are sharply different from their homeland. In winter, there can be not only cold, but also frost. Young, tender branches and leaves that have grown in autumn and have not had time to get stronger, fall under the cold and freeze. Late fruit ripening forces the tree to vegetate until late autumn. As a result, the tree does not have time to prepare for winter dormancy and suffers greatly from cold winters.

They tried to restrain the growth of citrus fruits by grafting them onto a deciduous rootstock - trifoliata, or, as it is mistakenly called, wild lemon. This deciduous plant has a very slow growth and great resistance to cold weather. Trifoliata, withstanding twenty-degree frosts, grows well, for example, in Kyiv.

Trifoliata restrained the growth of grafted citrus fruits, but their frost resistance increased little. Like any deciduous tree, trifoliata has a pronounced period of winter dormancy. Even in a very warm winter or in a greenhouse, it has a winter rest. In lemons, oranges and tangerines, as soon as the sun warms up, sap flow begins. Moisture is wasted, and trifoliata root does not supply them with either water or minerals, and does not take away the products of the activity of the leaves. As a result, citrus leaves lose water and die from lack of it.

Grafted on seedlings of lemon or orange or rooted cuttings of lemon grow normally. In warmer countries, citrus plants are grafted onto evergreens, root systems which are capable of activity even with a little heat.

All these reasons lead to failures in growing citrus fruits not only here, in the Sochi region, but also to the south, in the Transcaucasus.

Fedor Mikhailovich Zorin took up the breeding of a frost-resistant mandarin. He crossed the most frost-resistant Shiva-Mikan with the Unshiu mandarin and selected the most frost-resistant seedlings from these seedlings. In order to increase the frost resistance of the seed plant, F. M. Zorin grafted them for “education” on the most frost-resistant plant, as we know, - trifoliate.

After a harsh winter, when citrus plantations died almost everywhere, even in the southernmost part of the country, Fyodor Mikhailovich and I examined his breeding site. Thirty-five-year-old tangerines, oranges and lemons were frozen to the root. But the hybrids of Shiva-Mikan with Unshiu stood, retaining the foliage completely. It was freezing, snow crunched underfoot, a gray gloomy sky hung over the black-blue sea, life froze, and these trees stood as if there were no frosts.

On the way, Fyodor Mikhailovich said:

Now I will show an even more interesting case: see the orange? In fact, this is a three-story plant. Below - the roots and part of the trunk - trifoliates, then - a mandarin stem, and an orange, bred from seedlings, is already grafted onto it. Look!

Bottom and top are alive and well. Of these three plants, the most frost-resistant tropholiata and "theoretically" the most tender orange remained alive, and the mandarin, more resistant than orange, died. So there is also a frost-resistant orange!

It was necessary to preserve this frost-resistant orange. The trunk of the tangerine was not all dead, a narrow strip of bark could somehow give water to the crown; but soon she will die. F. M. Zorin had to plant a long thin seedling of trifoliata and graft it to the crown of an orange. And not just one, but several. The appearance of such a plant "on crutches" is somewhat strange, but it is important that the frost-resistant orange be preserved.

Scientists spent a lot of effort on preserving citrus fruits in cold weather. Used for this oil heating pads, shelter of corn straw and multi-layered gauze. Developed methods of surface and near-wall culture, but all this does not save citrus plants from death in harsh winters. Shelter can only save small trees in mild frosts.

Breeding citrus fruits from seeds, cultivating them in harsh conditions, using the Michurin method of raising them on frost-resistant rootstocks will make it possible to change the natural requirements of an evergreen plant that is weakly resistant to frost. Only in this way will we get a plant that has one period of growth, is productive, with excellent fruits and is not afraid of our frosts.

The first stage has been passed, and F. M. Zorin's success in this regard is obvious. It is proven by the harsh test of winter.

There is another way to cultivate citrus fruits - their indoor culture. More precisely, growing lemons in the winter in the room, and in the warm season - in the yard.

When growing citrus plants, you need to remember several features of such a crop. What is good for lemon is bad for orange and tangerine. Growing oranges and tangerines in tubs will produce them much more acidic than those grown in the ground, which are supposed to be sweet. In lemon, the acid is just positive quality. So, we should talk mainly about tub culture of lemons.

For tub culture, you can graft a lemon on seedlings of lemon and orange or root its cuttings. The best decoration of the room is a well-formed lemon bush with fruits just set and ripening, with buds and flowers emitting a wonderful aroma.

Citrus trees are very vulnerable to cold weather, and even frost-resistant varieties need care when frost comes.

For the care of young trees up to the age of four, the most effective method protection from the cold is to make a mound of clean soil around the tree trunk at a height of about 30 cm. The soil is a good insulating material that can protect the tree in frosts down to -9 ° C. It is also an absorbent of sunlight, so remove mulch or any other material covering the ground. You can mound around the trees in the fall before frost hits, remove the mound in the spring after. How will the threat of frosts pass? Another way to protect the trees is to wrap them with seedling protection paper. This is an alternative to creating a mound around the trunk, or you can use both the first and second methods at the same time for additional protection of trees.

To care for older trees, use special winter coatings. Just carefully cover the branches with a special protective material. If the frost is severe, you can place several lamps under the bedspread, or a small heater. However, be extremely careful when placing any heat source under the covers. Keep heat sources away from wood and bedspreads. You can use special "quilts for trees." They are sold already pre-cut specifically for covering a medium-sized tree. On average, these "quilts" help the tree to withstand temperatures 6-8 degrees lower. "Blankets" are used continuously for up to three days. If there is a need to use them for a longer period of time, it is necessary to remove them for the day so that the tree receives some sunlight during the day. Never use plastic covers to protect against the cold, always use "breathable" materials specifically designed to protect foliage.

If your tree has reached a size where the cover is no longer suitable, prepare for frost as follows: First, clear the soil around the tree of mulch to allow the ground to absorb sunlight. In the days leading up to frost, improve the heat absorption properties by irrigating the tree and the area around it. You can also spray the tree special means to improve frost resistance, which creates a special invisible film on the leaves and branches of the tree, helping to reduce frost damage.

The last way is to spray the tree with water during frost. Mount the sprinkler above the tree and start spraying when the temperature drops to -1°C. The ice formed from the water will protect your tree. However, be prepared for the possibility of branches breaking due to the weight of the ice.

Frost damage on citrus trees

Frost damage on citrus occurs when water inside the fruit, leaves, tree branches, and trunk freezes, rupturing cell membranes. Unlike deciduous trees, which protect themselves from the cold by shedding their leaves in autumn and going dormant, citrus trees continue to grow year-round. An extended period of cold weather even before frost forces citrus trees to prepare for this. This is why sudden changes in temperature - sudden freezes followed by warming - are more detrimental to citrus fruits than a gradual decrease in temperature. However, almost any frost leads to some kind of damage.

No matter what steps you take to protect yourself from the cold, there comes a point where nothing can help and your citrus fruit suffers frost damage. But if the damage is not very serious, efforts and support are required from you so that the tree can be restored. One of the important key points is not to take any steps immediately, but to wait until the damage caused by frost appears. In some cases, the death of a branch can occur even two years after freezing. If you act too quickly, you run the risk of cutting off parts of the tree that can recover from freezing, or vice versa, leaving those parts of the tree that look healthy, but are actually fatally damaged.

Signs of frost damage

Fruit

If the fruit is damaged by frost, the flesh suffers, while the skin may appear intact outwardly. Periodically, spots may appear on the fruits. Severely damaged fruits may fall from the tree; however, this may not happen if the damage is moderate. In any case, over time, the frozen flesh of the fruit will thaw, and the fruit will be empty.

Leaves and branches

Signs of damage on the leaves of citrus trees can be deceiving, as they will be green and springy at first. And only later, when they thaw, they become soft and fall off. In case of minor damage, frost-damaged leaves can recover. However, if the damage is fatal, the leaves will completely lose their structure, dry out and fall off. But leaf fall alone does not indicate the death of the tree. If the tree itself remains healthy, it will recover and growth will resume in the spring. As for branches, damage to branches almost always results in leaf death. In case of severe damage, the leaves will dry out, but may still remain on the branch for some time. However, if the branch is not severely damaged, the leaves will fall off more quickly.

Branches and trunk

Signs of frostbite of branches and trunks are the delamination of the bark and the formation of cracks on it. Lesions can manifest as plant cancer (necrosis of fruit plants), which is mistaken for late blight.

Pruning trees damaged by frost

The first step in pruning is to wait until late spring or early summer. This will give time and opportunity to assess the damage. In addition, trees damaged by frost may sprout in early spring, which will soon die off. By postponing the trimming process, you can save time and effort.

When pruning, always remember that it is best to trim the wood where the branches form a fork, making sure you cut off any damage. If young trees have been protected by an embankment, they can survive, recover, and sprout new shoots at the top, even if you have to cut branches above the embankment.

At severe frosts the tree can be damaged all the way to the ground. In such cases root zone may encourage the development of new shoots and the tree is likely to recover. But if it is a graft and the tree is damaged below the bud, new growth will start from the root shoot, not from cuttings. And then it is necessary to decide whether to carry out cuttings or allow new shoots to grow from the roots.