How are pecan trees pollinated
It Takes Two (or More): Understanding Pecan Tree Dichogamy
A common question asked by homeowners is “Can I plant just one pecan tree in my yard or pasture?” To sufficiently answer this question, we must first discuss the dichogamy of a pecan tree and how it affects pollination.
For most horticultural plants to successfully produce a crop, viable pollen must be present when the female flowers are receptive for pollination. This is true both for bee-pollinated plants and for wind-pollinated plants, such as pecan. Adequate pollination of a pecan tree is critical for the yield and kernel quality of the nut.
Most fruit trees have flowers that are considered complete, with each flower having a pistil (female) and stamen (male) reproductive structures. However, pecans are different because they have separate male and female flowers on the same tree. They are physically located on different parts of the tree, with the female nutlets (Figure 1) emerging from current season growth, and the male catkins (Figure 1) developing on last year’s growth. But in addition to being physically separated, the male and female flowers do not mature at the same time, which is called dichogamous flowering.
If that isn’t confusing enough, pecans take it one step further. You can find some trees that mature the male flowers first followed by the maturing female flower, with this sequence being a Type I or protandrous flowering. While another tree matures the female flower first followed by the male flowers maturing, which is known as a Type II or protogynous flowering. If male pollen release does not overlap nutlet receptivity then the tree has complete dichogamy, but if the timing of pollen release does overlap nutlet receptivity then the tree has incomplete dichogamy. Protogynous cultivars typically have long, thin catkins, while protandrous cultivars typically have catkins which are shorter and of greater diameter (Figure 2).
Why do pecans have this type of flowering? The simple answer is to maximize outcrossing which increases genetic diversity in native stands. More genetic variation leads to better pecan tree survival, continued evolution, and better climate adaptation.Trees with complete dichogamy must be cross-pollinated by another tree to set fruit. Cross-pollinated pecans are usually larger and higher quality than self-pollinated pecans. Self-pollination leads to poor nut growth and development, resulting in low quality kernels and increased nut abortion.
If you look at Figure 3, you can easily see that while Kanza (Type II) is a good match for Caddo (Type I), use of another Type II pecan such as Forkert would be a poor choice as a pollinator for Kanza or Caddo. Forkert’s pollen shed occurs well after the Kanza and Caddo nutlets are receptive. Therefore, it is imperative that you consult a pecan variety pollination chart (learn more at www.noble.org/cross-pollination-is-essential) when designing a pecan orchard to ensure there will be adequate pollination. It is recommended to find at least two to three varieties that shed pollen at the same time the main variety is receptive.
Research indicates that effective pollination may decrease at distances greater than 150 feet from a pollen source, so you must have pollinator trees no further than every fourth row. The duration of pollen dehiscence (shedding) for a cultivar may vary greatly in different years, as a function of variable weather and due to location of the orchards. Sustained high winds coupled with low humidity tend to shorten the period of effective pollination, both by accelerating pollen dehiscence and by shortening the period of nutlet receptivity. High humidity delays pollen dehiscence and extends the period of nutlet receptivity, according to research published in proceedings of the National Pecan Association in 1929. Small orchards may not need pollinator treesif native or seedling trees are within a few hundred feet of the new planting; however, large commercial plantings should include pollinatorswithin the orchard.
Long and Thin Catkins
Figure 2. Catkins of protandrous (Type I) pecan varieties typically have short, thick catkins (Pawnee, Oconee, Desirable), while protogynous (Type II) pecan varieties have long, thin catkins (Sumner, Schley, Stuart).
Type I and Type II varieties
When planning an orchard, both Type I and Type II varieties need to be included to ensure pollination of all varieties.
Common Type I or protandrous pecan varieties:
Common Type II or protogynous pecan varieties include:
However, it is not as simple as planting a random combination of protandrous and protogynous pecan varieties.
Pecan pollination chart
Figure 3. Pollen dehiscence is denoted by the yellow bar, and nutlet receptivity is denoted by the black bar.
Anther: The pollen-bearing part of a stamen (male flower)
Catkin: The pendulous spike of multiple male (staminate) flowers
Cross-pollination: In pecan trees, when pollen is delivered from the stamen (male) flower of one tree to the female flower of another tree
Dehiscence: The opening of anthers to release pollen, or “shedding”
Dichogamous flowering: When male and female flowers on a tree mature at different times
Dichogamy: Can be complete (if male pollen release does not overlap female nutlet receptivity), or incomplete (if the timing of pollen release does overlap nutlet receptivity)
Nutlet: The mature female flower structure of the pecan tree
Pistil: The female reproductive structure of a flower
Pollinator tree: In (or near) a pecan orchard, a tree that sheds pollen when the female nutlets on the main variety of pecan trees are receptive
Protandrous (Type I): Trees on which the male flowers mature first, followed by the female flowers
Protogynous (Type II): Trees on which the female flowers mature first, followed by the male flowers
Self-pollination: The acceptance by stigmas of pollen from flowers on the same tree
Stamen: The male reproductive organ of a flower
Reasons for Poor-Quality Pecans | Home & Garden Information Center
Pecans (Carya illinoensis spp. ) can be planted and cultivated in any soil in South Carolina aside from poorly drained soil, hardpan or stiff clays, or thin sands with a high water table. Trees should be spaced at least forty feet apart to provide sufficient room for future growth, good air circulation and light exposure. When selecting a tree for your landscape, a cultivar with good disease resistance is the most important factor to consider. Other crucial considerations include yield potential, nut size and quality, bloom or pollination type, precocity or age the tree begins to bear, and time of nut harvest.
There are a multitude of reasons why a pecan tree may fail to produce either the quality and/or quantity of nuts desired. This fact sheet will cover the most common reasons for poor production (quality and quantity) of nuts.
Pollination is the process by which pollen from the anthers of a flower is transferred to the stigma of the same flower or of another flower. This enables fertilization, which results in the development of seeds from the flowers. With pecans, pollination is the necessary first step for the production of nuts, and this is primarily facilitated by wind; insect pollinators are not actually a contributing factor.
There are several factors that influence pollination of pecans. First, there is the tree itself and the manner in which they produce flowers. Pecan trees are monoecious, which means that both male and female flowers develop on the same tree. However, the male and female flowers are formed in two separate locations, although in close proximity to one another on the tree’s branches. The male flowers are called catkins and produce pollen for pollination. The female flowers are called pistillates and require adequate pollen for nut development. The real issue is that these two flower types develop at different times. This creates a pollination problem because either the pollen production or the receptive female flower is past maturity when the other one is reaching maturity. If this occurs, it will result in a low percentage of flowers being pollinated, which in turn causes either low nut production or poorly developed nuts.
The most common solution to compensate for this is to plant two different cultivars where the pollen shed of one tree matches the timing of receptivity of the female flowers on the other tree, and vice versa. This means that to insure cross-pollination, trees of bloom Types I and II should be included in a planting. On bloom Type I varieties the pollen matures first, and on bloom Type II varieties the female flowers mature first. One may also see these bloom types listed in catalogs as proandrous (Type I) and protogynous (Type II). It is a common practice in the commercial production of pecans for growers to plant up to five different cultivars to ensure proper pollination.
For homeowners that live in an area with a sizeable population of wild or planted pecan trees, this generally does not become an issue. These trees provide additional pollen sources for wind pollination of the home orchard. However, the pollination may be inadequate if only one type of cultivar is planted.
The weather plays a critical role in pollination. Extremely low temperatures that produce a significant freeze will either damage or kill the female flowers and the catkins. Damaged or dead flower parts will impact pollination and overall nut production. The degree to which nut production will be impacted will depend upon both the severity and duration of the temperature extremes. For example, in the spring of 2014 a late frost impacted several pecan cultivars that were in bloom and reduced nut production by an estimated 50%.
Rain also greatly impacts pecan development. When the male flowers (catkins) are actively producing pollen, rain can wash the pollen off of the catkins down to the ground. This either reduces or eliminates the amount of pollen that may reach the stigmas of the female flowers. The longer it rains the greater the impact, and nut production may be significantly impacted. As noted earlier, wind is the primary source for transferring the pollen from the male flowers to the female flowers. Under normal weather conditions pollination is generally not a concern.
Proper nutrition is essential in order to maximize tree growth and nut production. Clemson University highly recommends soil testing in order to adequately address nutrient concerns and proper soil pH. The most reliable and commonly used tool for growers who are serious about maximizing nut production is the foliar or leaf tissue analysis. Together both soil and foliar tests provide a comprehensive approach for fertility and environmental sound nutrient management practices. They also can provide an economic benefit by not purchasing and applying unnecessary fertilizers. For additional information on these two tests and fees associated with them contact your local County Extension Service office, the Clemson Extension Home & Garden Information Center, or visit the Clemson Agriculture Service Lab. Additional information on soil testing can be found in HGIC 1652, Soil Testing.
It was common practice for many to make annual and/or bi-annual applications of fertilizer based on diameter of tree trunk and poor nut production. This is no longer the case. In fact, improper nutrient management, whether inadequate or excessive, is now known to cause more problems than benefits in nut production. The problem with these approaches is that excessive application of fertilizer promotes disease and insect pest issues that directly impact nut growth and development. On the other hand, the lack of proper nutrients will result in poor nut development and growth. However, in order for a grower to be absolutely sure about nutrient levels, a foliar analysis also must be conducted to identify any nutrient excesses or deficiencies.
So, the appropriate method for determining pecan tree fertility needs is to conduct both a soil and leaf-tissue analysis and to follow test recommendations for fertilizer and lime. For additional information on this visit the Clemson Agriculture Service Lab.
Zinc is an essential trace element required by pecan trees for successful nut production. A deficiency in zinc generally creates an abnormal growth pattern of the leaves known as a “rosette.” The most noticeable symptoms of rosette is bronzing and mottling of leaves; early defoliation; dead twigs in tops of trees; abnormally small nuts; small, yellowish, chlorotic leaves; short thin twigs growing on older scaffold branches with rosettes of small, yellowish leaves at the tips. An early sign is a wavy margin on the leaflets. Diagnosing such zinc deficiency symptoms is difficult because disease, insect pest, and mite infestations may cause similar symptoms. Confirmation based on a leaf tissue analysis is a standard practice in the pecan industry, and one that everyone should use.
Recently, horticulturists have gained a better understanding of zinc, soil pH and other nutrient interactions. Based on research, it is no longer recommended to make an annual application of zinc based on the diameter of the tree’s trunk because annual applications of zinc may result in an excessive amount of this trace element in the soils, which can lead to other problems and toxicity issues. The proper method is to conduct a leaf tissue analysis as discussed.
For additional information on this topic please contact your local County Extension Service office or the Clemson Extension Home & Garden Information Center. For information on leaf tissue analysis and how to collect a leaf tissue sample, please visit the Clemson Agriculture Service Lab.
Pecans are known to be an “alternate bearing” crop. This means that high yielding years will often be followed by marginally yielding years. This two or more year cycle is very common in most cultivars or varieties used today. Another contributing factor of this natural phenomenon is lack of either rainfall or irrigation water. Pecans originated in an area abundant in ground water and have a long history and need for water, especially during nut development.
Since the 1970s all commercial producers irrigate pecans in order to insure the best possible nut quality, and to reduce the differences in nut production (quantity) each year. An irrigated crop generally does not have as great of margin between years as a non-irrigated crop, commonly referred to as “dry-land production.”
Another contributing factor is inadequate fertilization. When a tree produces a large nut crop, it utilizes a large amount of nutrients and energy. If these nutrient deficiencies are not properly identified and replenished, there will generally be a reduction in yield the following year. To accurately determine which nutrients and their amounts needed, one needs to annually test both the soil and leaves as noted in the “Fertilization” selection above.
To help prevent alternate bearing, use sound cultural practices as noted. This includes both disease and insect control, and the proper use of fertilizer and zinc.
At times it can be a common occurrence for pecans to lose a majority of their leaves in either August or September. This is known as “early defoliating” and usually is the result of either an insect or disease outbreak or both. If this occurs, it can lead to a poor yielding crop the following year, as the leaves are the energy-producing agents of the tree. If the leaves are compromised, the tree will be less adept at regenerating energy lost in the year’s growth and production. Another cause of defoliation is drought. However, under drought stress, the leaf loss will be at a slower and steady rate. The best way to manage this potential issue is to scout for insects and disease and apply appropriate remedies for the problems, and to irrigate the trees as needed.
Probable Causes for Nuts Failing to Fill
Failure of nuts to fill is caused mainly by insect and disease damage to leaves and an inadequate number of leaves. Drought also causes failure to fill, if it occurs late in the growing season.
Premature Loss of Nuts
During many years a lack of pollination causes the greatest loss of nuts. Since pecans are wind-pollinated only, excessive rainfall during the spring bloom prevents pollination as noted earlier, and the poorly pollinated flowers produce small nuts that subsequently abort. Insect pest damage, disease pressure and drought are three other factors that can result in premature nut drop.
For more information on pecan diseases, please see fact sheet HGIC 2211, Pecan Diseases.
Prevent nut loss by harvesting early. Harvesting the nuts as soon as they mature ensures better quality. One of the quickest ways to lose nut quality is to let them lay on wet ground.
Originally published 03/00
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Pecan (Carya olivaeformis Nutt., nut family - Juglandaceae Lindl.) - grows naturally in the forests of the eastern half of the United States from Indiana and Kentucky in the north to Texas and Georgia in the south, also grows in Mexico.
In the subtropics of North America, the pecan reaches a height of 60 m and 2 m in diameter, in a more temperate climate, respectively, 30-40 m and 60-80 cm. The buds are yellowish, pubescent, the shoots are brownish pubescent when they appear, then glabrous. Wood of high technical quality is used in construction, for plywood, etc.
Leaves pinnately compound, up to 50 cm long, with 9-17 leaflets oblong-lanceolate, up to 15 cm long, 6 cm wide, with downward curved apex. Annual plants have simple leaves.
Flowers dioecious, placed on the same shoot, pistillate in short racemes at the end of it, and staminate at the base and in the middle of the shoot, in narrow long catkins, which are usually collected three together. The staminate flower consists of a tripartite leaflet and 5-6 anthers attached to it. A pistillate flower up to 0.8 cm long, 0.5 cm wide consists of a lower short bottle-shaped ovary with 5 bracts adhering to it, the sharp ends of which surround 2 small stigmas.
Pecan blossoms quite late, in mid-May or early June, its trees are dichogamous. The late flowering of the pecan ensures that it avoids damage from late spring frosts, but in subtropical conditions it is desirable to speed up its flowering. In this regard, in ARE, pecan trees were sprayed in early spring with 2 and 4% solutions of dinitrocresol mineral oil emulsion. As a result, pecan trees bloomed 1-3 weeks earlier, dropping of ovaries decreased and yield increased (according to Nasr, and Hassan).
The fruit of the pecan is a false drupe called a nut. It has an outer hard fleshy layer, a pericarp that hardens and cracks when ripe, and an inner endocarp (nut) with a smooth brownish shell and a core consisting of an embryo and two overgrown cotyledons with nutrients. The pecan endocarp is usually oblong or oval-oblong in shape, up to 4 cm long, 2 cm wide, with an average weight of 5–6 g. The endocarp shell is thin (up to 1 mm thick), the core is 50% or more of the endocarp mass, fat content is up to 70%. The composition of the kernel, in addition to fat, includes proteins, carbohydrates and vitamins. Fruit ripening occurs in October-November, but there are also early ripening varieties.
Mixed pecan root system with strongly and deeply developed central and lateral roots. The soil requires fertile, fresh or moist, but without stagnant water.
Pecan is a rather thermophilic plant. It grows well on the Black Sea coast of the Caucasus, as well as in Lenkoran, however, experiments on the introduction of pecans in the North Caucasus, in the Rostov region. and in Ukraine they show that it can successfully withstand winters with prolonged low temperatures reaching -30 ° C. Pecan belongs to rather light-loving species, such as ash.
Experiments show that the pecan is a fast-growing breed, reaching large sizes in a short period of time. Only in the first few years, its growth is slowed down, reaching 40-50 cm at the age of 2-3 years. grows and bears fruit.
At the time of fruiting, young pecan trees of seed origin enter from 9-14 years old, grafted - from 4-5 years of age. In the first years from the beginning of fruiting, the average yield of pecan trees ranges from 1 to 5 kg. At the age of 10-20 years, the average yield of a pecan tree in the United States ranges from 8 to 15 kg, and at 20-30 years old, from 11 to 22 kg. Old pecan trees bear up to 250 kg of fruit.
Over a period of more than a century of pecan culture in the United States, up to 150 varieties have been identified that differ in the shape, size and quality of fruits, productivity and resistance of trees to frost, drought, heat, insect pests and diseases. The best varieties promising in cultivation in our country include: Thomas, Schley, Busseron, Butterik, Posey, Major, Indiana, etc.
Pecan has been cultivated in North America since time immemorial. The native inhabitants, the Indians, highly appreciated the nutritional value of its fruits, constantly ate them and contributed to the expansion of its culture.
The annual production of pecan fruits in the USA reaches 130-150 thousand tons, the area of industrial pecan plantations is 150 thousand hectares. On plantations, varietal pecan plants are grown by grafting. Along with this, farmers also exploit wild pecan trees, which are regularly maintained (weeding, loosening the soil, fertilizing, etc. ).
Pecan culture in Europe has not yet become widespread and is concentrated in a small amount in Spain, Italy, France. Pecan is also grown in Greece, Turkey, the Middle East and many African countries.
In Bulgaria, pecan grows in the parks "Evksinograd" and "Vrana" on deep, fresh and light clay-sandy soils. At the age of 45, it reaches a height of 17 m and 30 cm in diameter, forms a straight trunk and a wide domed crown. Bears fruit annually. It is recommended not only for parks, but also as the main species in the forest cultures of the southern regions of the country.
Pecan has been cultivated in our country since the beginning of the 20th century. At first, its culture was concentrated in Batumi, Sochi and Sukhumi, then it spread along the entire Black Sea coast of the Caucasus, in Azerbaijan (Lenkoran) and in the republics of Central Asia.
In total, there are up to 10 thousand pecan trees in the USSR, most of which grow in Abkhazia. In this republic, plantings of pecans are found in forestries, state farms (Gagra citrus, Southern Cultures, Nursery, etc. ), on collective farms in the Ochamchire region, at the Kolkhida stronghold of the Sukhumi experimental station of VIR.
An interesting experience of growing cultivars of pecan was carried out at the Sukhumi experimental station of subtropical crops. Grafted pecan seedlings of various varieties obtained from the USA were planted here in 1933 along the banks of a small river. At present, they are well developed, successfully growing trees with high fruit yields. Particularly good growth are varieties: Schley, Western Schley, Busseron, Thomas, Major, Indiana, Butterick, Stuart, Posey, Agezura and Moneymaker. As L. Kh. Khashba established, almost all the main types of soils are suitable for pecan in Abkhazia: alluvial red and yellow earth, humus-carbonate and podzolic; as long as they are sufficiently moist, well-drained and slightly acidic.
Up to 100 pecan trees planted in the early years of the 20th century grow in Adler (a poultry farm and its settlement, as well as the park of the Southern Cultures state farm). Many of them reach a height of 35-40 m and 1 m in diameter, annually bear abundant fruit. The conditions for such growth are wonderful here: no winter frosts, more than 1000 mm of precipitation per year, fertile drained moist soils. The growth of pecans is also successful in Gagra, Gantiadi and other places.
In recent years, pecan plantations on an area of 22 hectares have been planted in various farms of Abkhazia and Georgia, more than 10 thousand pecan seedlings have been transferred to collective farms and scientific institutions for creating gardens, valuable forms have been identified, with which breeding work is being carried out.
In Azerbaijan, pecan grows well in Lankaran and Talysh, where there are large old trees that bear fruit every year. On the collective farm Hazi Aslanov created a pecan plantation near Lankaran on an area of 4 hectares. Trees grow well and bear fruit.
Successful introduction of pecan was carried out in the republics of Central Asia by experimental institutions. Since 1935, pecan plants have been planted here, which are now large fruit-bearing trees. V. M. Rovsky showed that on the fine-earth, drained and non-saline irrigated soils of Central Asia, pecan grows no less rapidly than in the humid subtropics of the Black Sea coast of the Caucasus. In the arboretum Sreda NIILKh near Tashkent, pecan trees at 9-year-old reached a height of 10.5 and 11.5 cm in diameter. In the arboretum of the Turkmen Forest Experimental Station, at the age of 17, the height of pecan trees was 12.4 m and a trunk diameter of 19.3 cm. in diameter.
In the dry growing conditions of pecans in Central Asia, flowering occurs a month earlier (in April) than in the humid subtropics of the Black Sea coast of the Caucasus. Fruiting here also usually occurs much earlier - in October.
The introduction of pecan in the Caucasus and Central Asia in our country, as shown by the results of experiments carried out over many decades, was crowned with complete success. Pecan has fast growth, immunity to diseases and high productivity in all areas of introduction.
In the more northern regions of the European territory of the USSR - in the North Caucasus, in the Stavropol and Krasnodar Territories and in the Rostov Region. there are plantings of individual pecan trees and small groups of them. Pecan culture is quite possible not only in these areas, but also much further north. Pecan easily tolerates winter frosts down to -36 ° C and is more winter-hardy than a number of such species as ailanthus, paulownia, walnut, etc. higher frost resistance of this breed. A. A. Fedorov, not without reason, considered the geographical latitude at which Kursk is located to be the northern line of pecan breeding in the European part of the USSR.
PG Krotkevich's conclusion is also very correct, that pecan, in terms of requirements for heat, is close to white locust and honey locust, in the community of which it grows at home. As you know, these species have perfectly acclimatized in Ukraine, and the white locust grows well and bears fruit even in Moscow and other areas close to it. The facts of successful cultivation of pecan in the Ukrainian SSR inspire confidence in the prospects of its culture in more northern regions.
The systematic introduction of pecan in Ukraine began in the 50s of the XX century. ex. Forest Institute of the Academy of Sciences of the Ukrainian SSR in Kyiv. Expeditions were carried out to the Black Sea coast of the Caucasus, where the growth, condition and productivity of pecan trees were studied. From the received seed material in 19In 1953, 1.5 thousand one-year-old seedlings and 1.7 thousand two-year-old pecans were grown in Goloseevo.
Sowing seeds was planted in the farm "Feofaniya" near Kyiv, the first mother plantation of pecans on an area of 1 hectare. A large number of pecan seeds and seedlings were sent in the 50s to forestries, botanical gardens and experimental institutions in the Kyiv, Cherkasy, Poltava, Kirovograd and Chernivtsi regions, as well as to Moldova, Latvia, the North Caucasus and other places. In many places, pecan trees still grow today. In some places they have already begun to bloom (in the Odessa, Kirovograd regions, etc.).
Separate young pecan trees grow in many botanical gardens of the Ukrainian SSR and in arboretums of many experimental institutions and forestries. The cultivation of pecans in the irrigated park Askania-Nova, Kherson region, deserves attention. At the age of 12, the pecan tree reached a height of 7.6 m and 6 cm in diameter, at the age of 15, respectively, 9 m and 11 cm, and at the age of 25, 12 m and 14 cm.
in the Transcarpathian region In the city of Mukachevo, in the estate of the Transcarpathian Forest Experimental Station, the pecan at the age of 10 reached a height of 8 m.In 1959, a group of pecan seedlings was planted in the amount of 88 specimens with a distance between plants of 1X1 and 1x2 m. C, the absolute minimum is -32 °C, the average July temperature is 17.9 °C. Annual rainfall, according to long-term data, is 782 mm. The climate is moderately warm and mild. At the age of 10, the pecan reaches a height of 3. 7 m, its condition is good, its safety is high (according to P.I. Molotkov).
An alley of pecans has been created in the Vasilyevsky forest nursery of the Izmail district of the Odessa region. In total, there are 45 trees in it, which have already entered the fruiting season.
Pecan culture in the Crimea is associated with the planting of this breed in the Nikitsky Botanical Garden by its creator X. Steven in 1824. Centuries-old trees of the Steven planting existed until the 30s of the XX century. They were distinguished by good growth and productivity. Currently, there are uneven-aged fruit-bearing pecan trees. Separate pecan trees grow on the estate of the Agricultural Institute in Simferopol, on the Vinogradny state farm and other places.
This review shows the full possibility of expanding the culture of this breed in Ukraine. Particularly favorable areas for the distribution of pecans in the Ukrainian SSR will be the western and southwestern ones. Under the condition of land irrigation, pecan culture is also possible in the southern steppe regions of Ukraine. At the same time, the weak expansion of the culture of this valuable breed in Ukraine should be noted. There are still no large industrial pecan plantations here, and insufficient selection work is being carried out to breed early-fruiting varieties with early fruit ripening.
In order to spread the pecan culture in the Ukrainian SSR, the UkrNIILKhA conducted research with this breed for a number of years at experimental stations in the forest-steppe and steppe zones of the republic (headed by F. L. Schepotiev). Seeds of various varieties of pecans obtained from Sochi, Adler, Sukhumi, Batumi, Uzbekistan, Tajikistan and other places were sown in the Kirovograd, Kherson and Kharkov regions. In total, about 10 thousand seeds were sown, from which no more than 3 thousand plants were grown and preserved. The data of phenological observations and measurements showed good germination of pecan seeds. It was also established that seedlings of Sukhumi origin of varieties Thomas, Butterik and Busserson were distinguished by high frost resistance. Of the Central Asian frost-resistant varieties, Shredder's Memory and Harvest varieties should be noted. Very weak frost resistance was shown by plants of Adler and Sochi origin, basically they all fell out. Of the surviving plants in 1965 and 1966 pecan plantations were established in the following locations: in the Kirovograd region. in the Veselobokovenkovsky arboretum on an area of 12 hectares, in the Kherson region. at the Prisnvashskaya agroforest reclamation experimental station on an area of 5 hectares and at the Tsyurupinskaya experimental vineyard station on an area of 1 ha. Currently, the pecan trees on these plantations have already begun to bear fruit. The average height of pecan trees at the age of 20 is 5.4 m, the highest is 6.9 m. The influence of aqueous solutions of gibberellin at a concentration of 200-300 mg/l was tested. Seeds were soaked in solutions for 2 and 4 days, after which they were sown in the nursery. It has been established that gibberellin stimulates the germination of pecan seeds and increases their germination. At the same time, seedlings in the experiment appear much earlier and more amicably than in the control, where the seeds were not treated. This ensures better growth of experimental plants and their earlier preparation for winter, which in itself is of great practical importance in introduction experiments on pecan acclimatization. It was also noted that a 2-day exposure of pecan seeds in aqueous solutions of gibberellin had a more stimulating effect on germination energy in most variants of the experiment than a 4-day one.
The data of Egyptian researchers T. Nasr, E. Hassan in 1975 also showed that gibberellic acid at a concentration of 100 and 200 mg/l after exposure for 24 hours increases the germination of pecan seeds and stimulates the growth of seedlings. However, this applied to seeds that had undergone stratification for 4 weeks. After a 2-week seed stratification, gibberellin did not have a positive effect on germination.
In the experiments of R. Taylor in 1972, the bases of the stems of young seedlings of pecans in a greenhouse were treated 4 times with lanolin paste containing gibberellin. After 3 months, the experimental plants were ready for budding, and the control plants were used only at the end of the second year of life.
We also carried out experiments on the effect of ultrasound on the germination of seeds and the growth of pecan seedlings. Under the influence of short-term (4-7 min) exposure to ultrasound, the germination of pecan seeds sharply increased, the growth of seedlings increased, the seedlings completed their growth processes faster and turned out to be better prepared for winter than control plants. Thus, the positive value of growth stimulators in the introduction and acclimatization of pecans was clarified.
Interesting data were obtained by us in studies on the distant hybridization of pecans with walnuts, which began in 1958 g. The task of these studies, on the one hand, was to obtain hybrids with increased frost resistance, early onset of fruiting, characteristic of walnuts, and on the other hand, hybrid forms with late flowering, high fruit quality, and productivity characteristic of pecans. Crossing walnut with pecan was carried out in the elite walnut garden in the Kupyansk forest nursery, Kharkov region. Backcrosses of pecans with walnuts were carried out at the Sukhumi station of subtropical cultures, where fruit-bearing pecan trees grow. Pollination of walnut flowers in Kupyansk was carried out with pecan pollen obtained from Uzbekistan, and pecan flowers in Sukhumi - with pollen from Kharkov region.
In total, between 1961 and 1965, 5796 flowers of walnut, pecan and other Juqlans species were pollinated in intergeneric crosses. Of this amount, 202 hybrid fruits were obtained (3.4% of the number of pollinated flowers).
In terms of size and weight, the hybrid fruits did not differ much from the fruits obtained on mother trees as a result of natural pollination. Hybrid fruits were sown and 79 hybrids were grown from them, which successfully grow at the Prisivashskaya agroforestry reclamation experimental station and in the Veselobokovenkovskiy arboretum. The highest height of walnut-pecan hybrids at 2 years of age is 104 cm, at 4 years of age 185 cm. Over a 3-4-year period of observation of hybrid seedlings in nurseries, their complete winter hardiness in these climatic conditions, the timely start and end of the growing season . Of great importance for these areas is the high drought tolerance of hybrid pecan plants. Spring 1966, all hybrids were planted from the nursery to a permanent area in the plantation, where they grow now.
The experiments carried out theoretically show the full possibility of intergeneric crossings in the Walnut families, and in practical terms, the possibility of successful acclimatization of such valuable heat-loving breeds as pecans, using distant hybridization methods.
Pecan reproduces by vegetative and seed means. The methods of its vegetative propagation include propagation by grafting, root offspring and cuttings. The most common method of grafting in the culture of pecan varieties. Seedlings of wild forms of pecan, or white hickory (Carya alba C, Koch. ) serve as the stock of grafts. Pecan vaccinations in Abkhazia are done during the period of strong growth of shoots in June, as well as in August and September. Budding is carried out in a ring or a half ring in 2-3-year-old rootstocks, the survival rate of eyes is 80-90%. At the Vakhsh station (Tajikistan), budding with a shield without wood turned out to be the best method of grafting, giving a survival rate of buds of more than 90%.
Pecan also produces root offspring that take root well when transplanted. You can also propagate pecans from root cuttings.
To propagate pecans by shoot cuttings, young shoots that have begun to lignify are used. The cuttings are 25-30 cm in size, 1 cm thick. The cuttings are treated with a solution of alpha-naphthylacetic acid (250 mg / l) for 24 hours or with indolylbutyric acid and, after treatment, are planted in a cold greenhouse or greenhouse, preferably with artificial fog. Rooting experiments on pecan cuttings by I. E. Smith et al. at 1974, 1975 in Africa, showed that semi-lignified cuttings 25 cm long rooted by 83%.
Pecan seeds are sown in autumn after harvest or stratified 60-90 days before spring sowing. Pecan seeds are stratified in the same way as walnut seeds.
Sowing of pecan seeds is carried out in nurseries in a row way or in furrows in beds. Seeding depth is 6-8 cm, 18-20 seeds are sown per 1 m. seeds. Crops are mulched and watered in dry conditions. Shoots appear in a month. Care of crops consists in weeding weeds and loosening the soil. Annual seedlings have a height of 10 to 25-30 cm. Well-developed seedlings are suitable for transplanting at 1 year of age, small ones only at 2 or even 3 years of age. Pecan seedlings for rootstocks are grown in the nursery school department.
In addition to pecan garden plantations created by planting varietal seedlings, this breed can be grown by sowing seeds immediately in a permanent place or by planting seedlings in forest plantations, in landscaping roads and settlements. Distances between pecan trees in rows and between rows on plantations in Abkhazia are recommended to be 15–20 m, in forest crops and avenue plantings they can be 10 m. etc. Caring for planting pecans consists in carrying out regular weeding and loosening the soil, caring for the trunk is necessary in order to remove a stem 1.5–2 m high, similar to the same operation for walnuts.
Planted pecan trees in our country are pest-free and disease-free. At home in North America, the pecan suffers from scab (Fusicladium), which affects the shoots, leaves and fruits. Especially often this disease affects pecan trees growing in southern North America in humid conditions. Scab is detected as a cluster of dark brown and dark spots on the affected areas, leading to drying out of the trees. Control measures - spraying with Bordeaux liquid at least 4 times during the growing season. Essential measures are the selection of pecan varieties immune to this disease, proper housekeeping in plantations, sanitary felling and destruction of affected branches, etc.
Other pecan diseases include galls, rosette and leaf spot.
The main pests of pecans are the black aphid (Myzocallis), scale insect (Melanaspis), pecan or hickory weevil (Curculio). These insects are controlled by spraying trees with various permitted pesticides.
Instructions for growing pecans. VioSad company statistics
Choose at least two different varieties of pecans for the best cross-cutting.
Internet shop VioSad promotes the best varieties of pecans, introduced for brewing in Ukraine.
It is recommended to respectfully read the description of roslin and request varieties for sawing, proponated in our online store.
Try to plant pecan saplings on the day of harvest.
Before planting, zanurt їх by the water for a few years, to refresh them, so like pea pecans - vologodny roslina.
It's smart to choose a place to plant your pecan.
Choose a sunny and windless space.
Pecan peas grow great, with a hostile root system, it is to blame for this between trees, but not less than 15-18 meters, one per one, that one per bud.
The soil is due to well-drained, richly nourishing loam.
The soil pH is due to buti 6.0 - 7.0.
Pecan peas love neutral and slightly acid soil.
Pecan trees grown on such soils do not require annual crops, nitrogen or zinc.
If your soil is too dry or you may need to water your tree more often.
Planting pecan peas
Planting a pecan tree is necessary in a calm place in the autumn or on the ear of spring.
1) Before planting, place the seedlings in water for a couple of years.
2) Take a close look at the shear root and straighten the vines of the root of the planting (it stimulates the natural growth), trim, if necessary.
3) Dig up the planting hole of the bedding deep, so that the shear roots spread freely and mow wide, for the placement of wild roots.
Planting hole, not guilty of but less than 1 meter in the depth of 0.5 - 0.6 meters of the top.
Important ! Do not top up the planting hole at any time .
4) Place the tree in a hole, trying not to harm to mow down the tough shear root and carefully place the bichni roots.
5) Fill the planting hole 3/4 full with water. (Water helps to protect damaged intestines near the roots).
6) Spread a ball of organic mulch (thyrsus, shavings, tree bark, needles, leaves, humus, hay, mowed grass, coniferous litter) along the root zone in order to trim the water and protect the plant from the weeds.
7) Remove 1/3 of the top of the tree, so that you can take root.
Important ! As long as the sadzhants are small, the first three rocks of the stink will require a defense against the sleepy opikiv and gryzuniv. Farm stovbur with white garden farboi.
Keeping an eye on pecan peas
In order for your tree to flourish and be healthy for a long time, it is necessary to look after it.
Properly pruning and fertilizing a tree will demonstrate better yield and vigorous growth.
How to fertilize hot pecans
Large trees should be treated with zinc sulfate, covering the leaves of the skin of 2-4 tyzhnі z birch by worms.
· Just recently planted a tree of good growth, closer to the middle of summer, add 200 g of ammonium nitrogen at a distance of 30 cm from Stovbur.
· Starting from another date after planting for 15 years, apply a small amount of nitrogen fertilization for wormwood.
· After 15 years, fertilize only in birch, and then - in grass.
Important ! Dobriva must be applied on a width of 25 - 30 cm from Stovbur .
Watering pecan peas
Pecan peas are also free-spirited, so during the summer season, water the tree 1 time per week.
Pecan pea pruning
Pruning should be carried out in early autumn or early spring, if the tree is at rest and before the ear of the active growing season.