Remontant varieties of raspberries, fruiting on annual shoots - the technology of cultivation of remontant varieties of the Rashbush - Rushberry group
Raspberry that gives autumn harvest
The generally accepted technology for growing existing varieties of raspberries, bearing fruit on two-year-old stems, is very laborious and energy-intensive. The main costs of manual labor are associated with the following operations performed annually:
- cutting of fruiting stems (without leaving stumps) and removing them from the site;
- the formation and pruning of annual shoots (normalizing them in the tape and bush) - removal of weak shoots appearing on horizontal roots at the same time, throughout the summer period, pinching the tops on the left annual shoots in August for their better ripening and preparation for winter, pruning frozen tops stems in early spring; garter stems to the trellis;
- bending them down for the winter and hilling them with snow for better wintering;
- pest and disease control;
- multiple harvests.
An alternative to the generally accepted technology, designed for a two-year cycle of raspberry crop formation, is a new original technology using remontant varieties that bear fruit on annual shoots in late summer - early autumn. This technology radically changes the way raspberries are grown, making it easier and cheaper. Varieties of this type are able to effectively use favorable environmental factors and avoid environmental stress due to a one-season cycle of crop formation and a special low-cost technology for their cultivation.
For the first time a sign of remontant raspberry would have been seen in the United States 200 years ago. Plants (young shoots of replacement) in the first year of life began to bloom and form a small crop at the tops of the shoots. During the winter, the tops froze out, and the next summer a crop was formed on the remaining part of the stem, as on ordinary varieties, i.e. such remontant varieties were assigned to the double fruiting group. In the domestic breeding of raspberries, no purposeful work was carried out to create remontant varieties, although in some cases forms were distinguished that gave berries on the tops of annual shoots. Known, for example, a remontant variety of raspberries, bred by I.V. Michurin, - Progress, which in the conditions of the southern regions of our country gives a small harvest of berries in the autumn ripening period, but forms the main harvest for the next year on the remaining part of the stem.
A number of remontant varieties have been created abroad (Sentyabrskaya, Herteij, Lyulin, Redwing, Zeva, Ottom Bliz, etc.) with predominant fruiting on annual shoots. Nevertheless, for the full ripening of their harvest, a frost-free period of at least 150-160 days and the sum of active temperatures above 3000 ° C are required, therefore, for central Russia, these varieties are not of practical interest, since their harvest has time to ripen before the onset of autumn frosts only by 15-30%. For the central and non-chernozem zones and the North-West, raspberry varieties with a shortened growing season are needed, in which no more than 130 frost-free days are required for the full ripening of the crop with the sum of active temperatures of at least 1800-2000 ° C.
Taking these conditions into account, since the beginning of the 70s, intensive work has been carried out on the creation of remontant varieties of raspberries at the Kokinsky base of the All-Russian Institute of Selection and Technology of Breeding and Nursery, a corresponding member of the Russian Academy of Sciences, the famous breeder I.V. In 1973 he created the first domestic variety of the remontant type, Indian Summer, with predominant fruiting on annual shoots. This variety became widespread in the Central Black Earth region and southern regions of Russia, where it was introduced into the zoned assortment of raspberries with a potential yield of 10-12 tons of berries per hectare. However, in the conditions of central Russia, by the beginning of stable autumn frosts, no more than 50-60% of the crop has time to ripen.
The test of this variety in the North-West showed that the fruiting zone of the Indian Summer variety on annual shoots reaches 25-35 cm only in a warm, prolonged autumn. The rest of the crop is formed the next year on the remaining two-year stem. Hence, here it also belongs to the double-fruiting group.
Further numerous series of crosses of remontant parental forms within the species of red raspberry turned out to be unpromising, since all the best selections, although they surpassed the variety Indian Summer in some indicators, also did not have time to bear fruit before the autumn frosts. In order to achieve the desired results in obtaining remontant varieties with single fruiting, which manage to yield crops on annual shoots in late summer - early autumn, it was necessary to change the plants so that they have the ability to start early and quickly grow shoots, rapidly pass dormancy (or differentiate buds, bypassing dormancy), early flowering and fruiting on all lateral branches formed in the year of shoot growth (and not only at the top of a one-year shoot).
All this was achieved through selective breeding. A positive result was achieved by I.V. Kazakov (corresponding member of the Russian Academy of Agricultural Sciences), who brought out qualitatively new remontant varieties of Babe Leto-2, Hercules, Aprikosovaya, Augustina, Nadezhnaya, Elegant, Monomakh's Hat, Bryanskoe Divo, Golden Domes and others, as well as V.V. Kichin, who created the Kalashnik variety. A breeding breakthrough in the creation of these remontant raspberry genotypes was obtained by crossing different types of raspberries: red, black, hawthorn, fragrant, wonderful and raspberry.
The development of shoots of these varieties from the beginning of growth to the ripening of the main part of the crop fits in one season, and for their name it is recommended to introduce the term Rashbush (rapidly branching bush) or Rushberry (swift berry). The original technology using remontant varieties with single fruiting in late summer - early autumn radically changes the way of cultivating raspberries, making it simpler, less costly, and allows you to get environmentally friendly products. Its essence lies in the fact that after harvesting, ripe on annual shoots, with the onset of autumn frosts, the entire aerial part of the raspberry is mowed with a scythe or cut with a pruner. From the spring of next year, new shoots grow, which will yield again in early autumn, and after fruiting they are cut again.
Thus, a one-year crop formation cycle is maintained annually. This eliminates the need for:
- formation and pruning of shoots;
- installation of trellises and garters of shoots to them;
- the use of chemical means of protection is excluded, since removing the cut shoots from the plantation allows you to get rid of the main diseases and pests, and, consequently, to get an ecologically clean crop;
- the need to protect plants in winter is eliminated, which makes it possible to expand the area of cultivation of large-fruited, but insufficiently winter-hardy varieties;
In addition, the advantage of this technology is the number of berries: autumn berries are larger and cleaner (not wormy), since the phenophases of the development of the raspberry beetle and the formation of autumn berries do not coincide. The cultivation of Rashbush remontant varieties allows to extend the period of consumption of fresh raspberries by 1.5-2 months, and together with summer varieties - up to 5 months. At the same time, the sale of berry products of remontant varieties in the "off-season" time is carried out at higher prices than in summer, which stimulates the creation of raspberry plantations in all categories of farms.
At the same time, when growing remontant raspberries with single fruiting, negative aspects are not excluded:
- annual shoots can be affected by spider mites, raspberry mites, shoot gall midge, purple spot, therefore, in order not to risk the harvest, it is necessary to plant plantings with healthy planting material;
- the absence of an aerial part of plants on the plantation in the late autumn period can affect the freezing of the soil, so you need to take care of the root system, covering it and ensuring good snow retention.
However, these minor negative points cannot diminish all the advantages of the new technology using remontant varieties that give a one-time yield on annual shoots.
Cultivation technology of remontant varieties of the Rashbush group (Rushberry)
The place for the future raspberry tree is chosen especially carefully. An indispensable condition is placement in a sunny, well-lit area of the site, protected from the wind. Observations have shown that the timing of the beginning of flowering is strongly influenced by the illumination of the site. In shading, flowering occurs later, the plants cannot show their full potential and sharply reduce the remontant zone, delay the beginning of berry ripening or do not produce a crop at all.
The best soils are well-fertilized medium and light loams with neutral or slightly acidic pH = 6-7.
It is advisable to prepare the soil in a pre-planting rotation, alternating between clean fallow - occupied fallow - green manure fallow, i.e. one year the land is not occupied with anything, but organic fertilizers are applied and loosened, destroying weeds. In the second year, crops are grown that help get rid of weeds, but do not reduce soil fertility. And on the third, crops are sown that quickly create green mass (green manure), and they are embedded in the soil as green fertilizer. In all other respects, the soil is prepared as on a regular raspberry plantation.
Low-fertile soils are annually improved by the introduction of increased doses of organic fertilizers for autumn digging (10-15 kg / m2). Excessively moistened areas are drained by drainage or open ditches. In the northern part of the Non-Black Earth Region and in the North-West, with a close standing of groundwater and the impossibility of their drainage, you can plant raspberries on ridges, planting plants in furrows, the bottom of which is useful to lay out with various organic materials that give humus (wood chips, chopped brushwood, reeds, reeds, etc. .)
Medium-fertile soils are filled with fertilizers per 1 m2:
5-6 kg of organic fertilizers, 20-30 g of superphosphate, 15-20 g of potassium nitrate. In spring and autumn, fertilizers are applied annually according to generally accepted technology.
Considering the increased need of remontant varieties for nutrients and the impossibility of filling the entire area well, it is advisable to apply fertilizers to the trenches. To do this, in the direction of the future row, they dig a trench 0.5-0.6 m deep, at the bottom of which organic and mineral fertilizers are applied per 1 m of its length: 2 buckets of humus or compost, 1 glass of superphosphate and potassium sulfate. It is better to replace mineral fertilizers with 1 liter can of ash. Mix fertilizers with the top layer of soil and drop it to the bottom of the trench - the first layer. Then mix the bottom layer of earth with fertilizers (the same) and again throw it into the trench - the second layer. Tamp the trench lightly so that all the soil can fit in it, and plant the seedlings.
A similar method of pre-planting soil preparation - filling it with fertilizers - can also be used when planting seedlings in pits, introducing into each of them a half dose of fertilizers recommended for 1 m of the trench.
Plants placement during planting.
There are several ways to place raspberries when planting:
- single-row with a distance between plants in a row of 0.5-0.7 m, between rows of at least 1.2 m;
- tape - in 2-3 lines: between plants in a row 0.5-0.7 m, between lines 0.6-0.9, between tapes - 1.5-1.8 m;
- bush - the distance between individual bushes is 0.7 m;
- square-bush - plants are placed on the sides of a square with sides of 1-1.5 m;
- arbitrary - plants are placed in the sunniest and warmest places.
There are other placement methods used depending on soil and climatic conditions, varietal characteristics, the possibility of using film shelters and other factors. For planting, use standard seedlings, rhizomes, green offshoots with a clod of earth (nettle), green seedlings from root cuttings with a closed root system.
Mulching, watering, feeding
The soil in the rows is mulched with a black film, which prevents the bushes from growing to the sides and reduces the heat loss in the soil by about 15%. This is especially important for remontant varieties, because they, as a rule, experience a heat deficit in the conditions of the Non-Chernozem zone of Russia.
You can also use a light film for mulching, covering it on top with peat or soil with a layer of 2-3 cm. In addition, non-woven materials are also used. These mulch materials are spread in a row before planting the plants, and after planting they are mulched with bulk materials.
Convenient for mulching and kraft paper that is spread before or after planting.
Watering is combined with top dressing, passing them into the holes at the base of the bush from a hose or an ordinary watering can, as well as into the grooves on both sides of the strip.
The soil in the aisles in the future, under black fallow, is occupied either for sowing green manure, melliferous crops, or lawn grasses. The free area between bushes in rows can also be sown with grasses if there is no film there. Sow herbs before planting raspberries or at the same time, or after rooting of seedlings. The grass is periodically mowed, leaving the cut in place, and the green manure and honey plants are crushed and embedded in the soil.
Fertilizers are applied over the entire area within the time recommended by agricultural technology.
Formation of plantings. In the first year after planting, depending on the variety and planting material, 1-3 replacement shoots are formed. With a shoot height of 10-15 cm, the old aerial part of the seedling is cut off and burned. This technique promotes better development of young shoots and reduces the level of fungal infection.
After harvesting, the aerial part of the plants is completely removed. It is better to carry out this work with the onset of persistent late autumn frosts and when the soil freezes, since up to this time there is an active outflow of nutrients from the stem to the root system of plants. Shoots are cut at the very base of the soil, leaving no stumps. The soil must be mulched with peat, humus layer of 6-8 cm. This operation is carried out annually.
From the second year after planting, with the beginning of the growing season, the root suckers are normalized, leaving 5-15 strong shoots per 1 m of the strip. Subsequent growing root suckers are used as planting material, digging them out in the phase of "nettles" with a clod of earth, and planted in a prepared place.
With the bush growing method, the bushes are formed from 3-6 replacement shoots, depending on the degree of branching of the variety.
To rejuvenate the plantings, the old rhizome is removed from the plants every 4-5 years with a shovel with a narrow blade. This stimulates the formation of root suckers, the strongest of which are used to form new bushes.
Raspberry berries of the autumn harvest are large-fruited, clean (not wormy), high density and stay on the bush for a relatively long time after ripening without decaying.
Therefore, harvesting can be done in 5-7 days. They finish harvesting berries at the onset of frost -4 ...- 6 ° C.
The berry picking period can be extended if you use the simplest film shelters from frost. The unripe parts of the crop (buds, flowers, ovaries) are also harvested as a medicinal collection, dried and used for medicinal purposes.
With the aim of a more complete ripening of the crop in areas with insufficiently warm autumn, it is advisable to normalize the generative organs in the upper part of the shoot, where small berries are formed, and part of the inflorescences even dries up. To do this, you should first pinch the growing fruit twig when the first inflorescence is formed, then, as it appears, you need to break off 5-7 upper weak fruit branches, leaving 8-10 lower, stronger ones for fruiting. Such normalization contributes to the rapid development of the remaining fruit branches, their timely and friendly flowering, accelerates ripening and increases the mass of berries. At the same time, the total yield does not decrease, and almost all berries have time to ripen before the first frost.
Galina Aleksandrova, Candidate of Agricultural Sciences