Characteristics of pollination of different crops
Buckwheat. Buckwheat have flowers for bees of open type. They secrete abundant nectar, have a strong smell and attract bees to visit the flowers of buckwheat in the morning and collect nectar and pollen. Attendance of buckwheat flowers by bees during the day depends on many factors, but mainly on the concentration of sugar in the nectar and its quantity. Secretion of sugar in the nectar peaks at 10-11 am. The largest number of bees visit the buckwheat from 9 to 11 am, after 1 pm on a clear sunny day there are no bees on the flowers of buckwheat, as they no longer secrete nectar. Pollination by bees increases quantity of seeds on average by 1.5 times. Harvest increases by 26-30%.
Two families of bees are enough for effective pollination of 1 hectare of buckwheat. Increase of quantity of bees does not increase the harvest.
Pollination of oil seeds and commercial crops.
Sunflower is one of the most important honey plant of field crops, it is pollinated by insects and wind. The main pollinators of sunflower are honey bees. There is a definite relationship between the number of bees in the area and the yield of sunflower. After pollination by bees the quantity of developed sunflower seeds is 87-93%, without pollination by bees – 76-78%. The yield increases by 40-45%.
Sunflower blooms for two weeks. Daily two or three rows of flowers bloom from the periphery to the center of the basket. Usually the flowers bloom for 2 days, on the second day they can be fertilized and pollinated. With a lack of pollinators the flowering could be delayed, which would reduce the ability of flowers to fertilize.
The magnitude of the sunflower crop is greatly influenced by the saturation of bees. If you place on one hectare 0.25 bee colony, so the yield will be 11.8 centners, if 0.7-1.0 families – 16.7 centners. For effective pollination you should promptly bring up bees at the rate of 0.5-1 bee colony per 1 hectare. The glut of bees gives little additional yield. The best time for pollination is from 10 to 16 hours.
Mustard is an aromatic plant from which the bees collect nectar and pollen. Usually they go to the mustard in the morning (9-11 am). For effective pollination of this crop it is sufficient to place 0.5-1 families on 1 ha. Pollination by bees increases quantity of pods and seed formation, depending on the varieties of crop, by 12-50%.
Coriander is an aromatic plant, gives bees nectar and pollen, well visited by the bees in the period between 10 and 15 hours, it is required 2 families for 1 ha. It is better to arrange groups of families around blooming array.
Pollination by bees increases the yield and other oilseed crops, including winter and spring oilseed rape. Bees visit these good crops. Terms of transport and ways of placing of hives are the same for all the crops, well visited by bees.
Cotton. Flowers of cotton are capable of self-pollination, but cross-pollination greatly increases the yield of seeds and fibers and improves the quality of cotton. Long staple cotton varieties abundantly secrete nectar and are well visited by bees. After pollination by bees the box’s weight increases by 12-18%, the number of seeds – by 6%, weight of seeds – by 3-8%, the mass of cotton – by 40%. Bees accelerate ripening by 5-9 days as compared to self-pollinated flowers.
To pollinate cotton you need 5-6 families of bees on 1 ha. Sometimes bees are trained with flavored dressing to increase pollination.
Flax is capable of self-pollination, but may be cross-pollinated. The use of bees for pollination of flax provides significant yield increase. After self-pollination, there are 2902 seeds in 500 boxes, after pollination by bees – 3393 seeds. 1000 seeds’ weight, respectively, is 5.15 and 5.28 g, for better pollination bees are trained.
Pollination of fruit and berries. Almost all kinds of fruits and berries are typical entomophilous plants. Pistil stigma of many species of fruit matures before the anthers, that excludes self-pollination of flowers with their own pollen. Most varieties of apples, pears, plums, cherries and other fruit crops do not give any fruit after using pollen of the same flower and tree, and pollen from another tree of this variety. Thus, the possibility of self-pollination of these plants is excluded by spatial isolation of the generative organs of the flower, and their physiological incompatibility. Even the varieties of fruit crops, which can form the fruit or berries after pollination with pollen of the same variety, give higher yield and better quality fruits after cross-pollination with pollen from other plants of the same variety.
People distinguish compatible varieties (pollen can pollinate the same variety) and incompatible, that is, their pollen does not cause ovaries. When you plant a garden, it is necessarily to plant the trees-pollinators near the trees of basic type. For better cross-pollination the tree-pollinator should bloom every year and together with the main. Tree-pollinator must be well adapted to local environmental conditions and has a good yield.
Usually they plant a row of pollinators after every 4-5 rows of the main variety. Do not increase the number of rows of the main variety, since with the distance from the trees- pollinators crops are reduced. Practice has shown that the highest fruit yield is obtained in rows adjacent to the rows of trees-pollinators, as there are favorable conditions for cross-pollination.
Apple and pear flowers without bees and other pollinators give few fruits – number of ovaries does not exceed 1-1.5%, while pollinated trees give not less than 20-50% of ovaries of the total number of flowers.
In case of insufficient pollination of flowers, for example, because of the rainy and cold weather, there is a massive shedding of ovaries from cherries, black currants. On isolated from bees gooseberry bushes the fruit yield decreases by 5-7 times.
Early in the spring there are usually very few wild pollinators in nature, so it is required two families for 1 ha orchard.
Apple tree is one the main fruit crops. Apple flowers are bisexual, stigma matures 2-3 days earlier than the anthers. The life span of the flower, depending on the grade, is 4-8 days. After cross-pollination by bees even self-pollinated varieties give higher yield of better quality fruits, sugar content increases by about 1%, acidity is reduced by 0,2-0,8%.
Organizing the bees for pollination of pome and stone crops, you should keep in mind, that in cold weather, which often comes at a time of flowering gardens, bees work within a radius of 200-300 meters from the location of hives. With the increase of distance the visiting and fruit yield decrease.
In case of the high number of flowers and low growth of the trees, you need to provide cross-pollination of the first-day-blooming flowers and to limit the pollination of flowers, blossoming in the following days, which will ensure shedding of excess ovaries and will not cause the periodic fruiting.
Pollination by bees is carried out for 2-3 days in a favorable weather. If there is not so many flowers, pollinate all the flowers or a substantial part. To do this, the bees are in the garden the entire period of pollination.
Beehives are brought into the garden in the beginning of flowering. Place the families in groups of 15-20 hives, at a distance of no more than 300 meters from each other. In commercial orchards with high density of the planting hives are arranged by one-two in one row of a garden. The bees stay in one place for 4-5 days, that is, as long as 50-60% of the total number of buds bloom. Then at night replace the hives. The transportation of apiaries and replacement depend on the timing of flowering of varieties, prevalent in the plantation. You should move apiaries for at least 3 km, to avoid returning of the bees to the previous location. Under this condition, the bees will frequently visit flowers in the period of maximum flowering of a garden.
Pear female generative organs mature before the anthers, which prevents self-pollination of the flower.
There are few self-pollinated varieties, but they give a higher yield of better quality fruits after the cross-pollination with pollen of other varieties. Planting of special varieties of trees-pollinators and cross-pollination by bees are necessary.
Plum is one of the most important and widely used stone fruits.
Most varieties of plums are unable for self-pollination. With proper organization of pollination by bees yield increases by 2-3 times.
Apricot and peach are also responsive to the cross-pollination. Some varieties of apricots need the appropriate varieties of pollinators.
Cherry is represented by many varieties. Some of them may not be pollinated by its own pollen, as the stigma out of the bud before maturing of male generative organs. The flowers of some varieties do not form pollen. Many varieties are incompatible, thus a careful selection of varieties of pollinators is needed. Cross-pollination significantly increases the yield and quality of cherries. In case of free pollination of flowers of cherry the fruit-setting is 11.1%, and with isolated flowers – 0.33%, the average percentage of fruit set with bees is 15%.
Raspberry is one of the most common fruit plants.
Raspberry flower can be pollinated with its own pollen, but the best pollination occurs with the participation of insects, because heavy sticky pollen can not be carried by the wind, and the pistils in the flowers much longer than the stamens. In a complex raspberry fruit each individual fruit can develop only as a result of fertilization of isolated ovary. In case of a lack of pollinating insects only a part of ovaries of the flower is fertilized, and you get small, underdeveloped, irregularly shaped fruits of poor quality.
Black and red currant can be pollinated with their own pollen, but it is better with insects, the leading role is played by honey bees.
Without insects only a small number of flowers form the ovaries. After pollination by bees yield increases by 18-44%.
Gooseberries have flowers, adapted to cross-pollination, as the anthers ripen before the stigma of the pistil.
Adhesive and relatively heavy pollen can not be transported by wind. Fruit-setting without insects can range from 9 to 35.6%.
Strawberries. Most varieties have bisexual flowers, which can be pollinated within the class. But there are kinds, in which the stamens are underdeveloped and pollination is possible with pollen of another variety, so you need to plant a pollinator-varieties with well-developed male generative organs. To pollinate one hectare of strawberries you need 1-1.5 bee family.
Citrus. Tangerines and oranges give bees a lot of nectar and pollen, insects willingly visit them.
Cross-pollination of flowers by bees significantly increases the yield of citrus and improves the quality. For 1 ha of citrus trees you need 2-3 families.
Grapes. Most grape varieties have bisexual flowers and are self-pollinated. Some varieties without the pollen of other varieties can give only small seedless berries. Wild grapes is dioecious, its pollen is carried not only by the wind, but by insects. Wind as a pollinator is ineffective. His strength is sharply reduced in plantations, especially when the wind direction is perpendicular to the rows of grapes.
Transfer of pollen by insects increases the yield and quality of grapes. The flowers attract bees with pollen and nectar flavors. Bees like to collect pollen from the grapes.
To pollinate one hectare of grape you need one bee family. The hives are placed in such a way that the bees fly along the rows and down-up. You can reinforce the collection by taking the pollen from the nests with the open brood.
Pollination of Cucurbitaceae and vegetables. Melons are typical entomophilous plants with large bright dioecious flowers. Watermelons, melons, pumpkins and other cucurbits have flowers with only the female generative organs, and with only male ones. Bees increase yield of melon by several times, and increase the number of formed fruits.
Vegetable crops require cross-pollination by insects to produce seeds and fruits. Seeds, obtained by the cross-pollination by insects, are larger, growth vigor and germination are higher.
Testes of most vegetable crops bloom early, when there is not enough wild pollinators, so you need 1 family of bees for 1 ha.
Pollination of forage grasses. You need to intensify the pollination by bees, train them to fly to the smell of flowers. Training of bees and other techniques increase the pollination of flowers, thus increasing the yield of grass seed by 2-3 times.
Training of bees in the hive. Every morning during the flowering period you should place in each hive 100 g of sugar syrup, infused on the flowers of pollinated crops (eg, clover). Syrup prepared as follows: take 100 grams of sugar per each family of bees, and dissolve it in an equal amount of boiling water.
After cooling, put corollas of freshly picked flowers of clover (1/3 of the syrup) in the solution. After 11/2 – 2 hours syrup gets flavor of flowers. Distribute syrup every morning by 100-150 ml per family for the entire period of pollination. Before placing corollas in the syrup, grind them in a mortar. In this case, you need less corollas. During training the quantity of flights of bees increase by 5-7 times.
The red clover pollen is brown. It is markedly different from the pollen of other plants, blooming in the same period. Mix 1 liter of syrup and 10-50 g of pollen. Mix it at first in a small amount of syrup, and then mix with syrup, made for the whole apiary. Syrup can ferment quickly, so it is cooked before consumption.
Scaling up the bees to collect pollen. Pollination can be improved by increasing the quantity of open brood in the cells, while reducing the quantity of bee bread. It is recommended to take the frames with bee bread or remove the pollen brought by bees from their legs. In this case,pollination is increased by 2-3 times, and the yield of seeds – from 2.6 to 4.7 quintals per 1 ha. You can increase the amount of open brood in the bee family by putting of one or two frames with the larvae of other families, or making the queen to lay eggs. To do this you can give sugar syrup – 1 liter per family per day within 10-12 days.
Pollination of individual plants. Bees and bumblebees pollinate clover, and the bumble bees pollinate it better, but the number of them during the flowering period varies widely. It is safer to use the bees to pollinate clover, although they collect only a fraction of emitted nectar. The fact that the clover nectaries are located at the base of corolla, the average length of the flower tube is 9.4 – 10.5 mm (0.3”). The average length of the proboscis of bees is 6.5-7 mm (0.2”), so the bees do not always reach the nectar of these flowers. In a humid warm summer the nectar in the flowers rise by 1.5-2 mm(0.1”). The nectar of clover aftermath in dry weather is more accessible for the bees. Clover gives bees a lot of pollen.
Bees are placed directly at planting or within 500 meters of it. When you place an apiary within 600 m, the collection of seeds is reduced by 15-20%. Best results are obtained when you place at least four – six bee colonies per 1 ha. People use a variety of techniques to strengthen the pollination. You can place 10-20 hives per 50 hectares of clever. Apiary should be delivered in the beginning of flowering period.
Pink and white clover are cultivated as forage and pasture plants separately or mixed with others. Bees like to visit them, as the flowers produce a lot of easily accessible nectar.
White biennial sweet clover is not only yield fodder crop, but also a first-class honey plant. By mowing and planting of one-year clover you can achieve the flowering in autumn when there is no harvest. The number of bees used for honey yield from sweet clover is sufficient for its pollination. It is only necessary to deliver and correctly set hives.
Sainfoin. After pollination by bees the seed yield increases by 2-2.5 times. Pollination of sainfoin is not difficult.
Alfalfa has one feature, associated with pollination, its flower is designed so that one visit is not enough for pollination to occur. The generative organs of the flower (pistil and stamen) are closed by petals of a boat and are in a locked state. To pollinate it, insect needs to make some effort to release the stigma of the pistil from the mucous membrane and bring pollen, so a bee should shove proboscis into the center of the flower between sail and keel, and put legs on the wings of the corolla. A boat – generative column – breaks out of the petals and hits the base of the proboscis, and then presses to sail.
Wild solitary bees are active pollinators of alfalfa. During the evolution they anatomically and biologically adapted to pollinate alfalfa. However, the difficulty of using wild pollinators is that they cannot be trained, and the number of them annually decreases because of the intensification of agriculture and the use of pesticides.
During an abundant selection of nectar, the bees like to visit the flowers of alfalfa and often open them, but for a more effective pollination of this crop it is recommended to use strong bee colonies with lots of open brood (5-6 frames) in the loungers and double-hulled hives and 10 frames in multiple hives.
Bees are transported to seed fields in 3-4 days after the onset of flowering. 2-3 days before placing the bees you should mow around the field of alfalfa and mow cross swaths every 500-600 m. Bees are placed around the field and on the swath by groups of 50-60 families, providing a counter-pollination. To improve the efficiency of alfalfa pollination you can use the same methods for enhancing pollination activity of bees as for pollination of red clover. You need 8-10 bee colonies per one hectare. Alfalfa seed crop after pollination by bees reaches 3-5 centner per 1 ha.
Broad Beans are cross-pollinated and self-pollinated leguminous crop. Flowers of broad beans open in the afternoon, so the bees visit them mainly in the evening hours. Bee visits up to 250 flowers during one flight. Bees increase the number of pods and weight of broad beans. Yield of beans is increased by 30-35%. Bees collect 18-30 kg of honey from 1 ha.
Pea is also leguminous crop. It can be self-pollinated and cross-pollinated. Flowers abundantly secrete nectar, attracting a large number of bees and other insects. Main pollinators are honey bees. Bees increase the yield almost by 2 times.
The use of bees for simultaneous pollination of multiple crops. You can bring bees to the fields with buckwheat and clover, clover and sunflower. In such cases apiary is placed directly on the field of the crop, which is less visited by bees. When both crops are actively visited by bees, apiaries are placed between fields of these crops.
Monitoring the quality of pollination. Indicator of pollination efficiency is attendance, that is, the number of working bees per unit of area or per number of flowers (Table 47).
|Name of plant
The number of bees in one 100 m2
During 5 min 5 bees for 1000 flowers
Attendance of crops is defined as follows. Measure an area of 100 m long and 1 m wide. Passing along the area back and forth, the observer counts the number of working bees, which then is divided by 2 to get the average. If the scan reveals that the the quantity of working bees in the field is less than recommended, it is necessary to take measures to improve the efficiency of pollination.
|Name of plants
|Color of pollen
|raspberry, elm, henbane
|white and gray
|apple varieties (cultivars)
|buckwheat, honeysuckle, walnut, gooseberry, mint
|linen, oak, ash
|dandelion, alder, sunflower, clover
|horse chestnut, peach, apricot
|cherry, cherry, hawthorn, white clover , oregano, sainfoin, meadow knapweed (Pink)
|maple, basswood, ash, willow-herb (Fireweed)
|bruise, wild mallow