By: Avium Technical Team
According to the Food and Agriculture Organization of the United Nations, 84% of crops for human consumption depend on having been pollinated by bees. This process, essential for fruit setting, is governed by current regulations, which among other aspects regulate safety, transport, assembly, time of application of bees, among others..
Although cherry production involves a series of complex processes within the plant, pollination is undoubtedly one of the most magical moments of the season; it is then when, thanks to a natural phenomenon (although sometimes promoted by human action), the transfer of pollen from the anthers to the stigma of a flower is achieved (Gil, 2012), a process called pollination. This action can be carried out by two methods, the use of vectors, commonly bees (Apis Melífera), and an anemophilous process by means of transferring pollen through the action of the wind.
After this action, the germination of pollen from the stigma forming the pollen tube through the style of the flower to reach the ovary is the process defined as fertilization so that fruit set can later be declared.
In cherry trees, there are self-compatible or self-fertile varieties such as Lapins, Santina, Skeena, Staccato, among others, which means that their flowers can be fertilized with their own pollen. There are also self-imcompatible varieties, as well as self-infertile ones such as Regina, Kordia, Bing, among others, which, despite the fact that the pollen reaches the stigma from the anthers and germination occurs in the stigma of the flower, are not able to be fertilized because an incompatibility occurs in the style of the flower, preventing it from reaching the ovule. Independent of the type of variety, from the point of pollination, the pollen needs to move entomophilously or anemophilously. It should be noted that self-fertility is not always synonymous with high setting potential, as there are self-compatible varieties with low, moderate and high setting potential. The same consideration applies to those self-incompatible varieties. Given the above, we must take into consideration that each variety has a flowering date and certain compatibility (Table 1).
On the other hand, the incompatibility groups and genotypes in which the different varieties of cherry trees are currently grouped are separated according to their flowering date, grouped into early, medium and late flowering (Table 2).
It is important to highlight that all self-fertile varieties share the S4¨ Allele, which provides the character of total genetic compatibility and universal pollen donor for any other variety; however, regardless of this characteristic, the varieties to be pollinated must coincide at the same time of flowering.
In stone-bearing species, the transfer of pollen is mainly via entomophilous means, where the main vector agent is the bee (Apis mellifera). According to the FAO, 84% of crops for human consumption depend on having been pollinated by bees. On the other hand, Greenpeace estimates that without bees our productivity would drop by approximately 75%.
Given the above, the relevance of bees in agriculture worldwide is more than clear, especially with the drastic climate changes generated by global warming.
Chile, as a fruit industry, has generated work opportunities with a medium and long-term focus, mainly aimed at training beekeepers and farmers to be more efficient throughout the entire chain of the pollination process. One of the fruits of this work is the pollinator manual, a work carried out jointly by the National Association of Seed Producers (ANPROS), the Federation of Fruit Producers (FEDEFRUTA) and the National Beekeeping Network Federation (RAN FG).
Among the points that stand out most in this manual are the following:
1) Current regulations:
According to exempt resolution No. 8,196 of 2015, the obligations of a beekeeper are the following:
-During the month of October of each year, beekeepers must declare the existence of their apiaries in paper format before the Official Livestock Information System (SIPEC).
-Every beekeeper must have an internal record of the movement of hives, indicating the identification of the apiary(ies), its origin (region, commune, locality, start and end date of pollination).
2) Safety Considerations:
Moving Beehives:
-Prefer night or early morning transfers. If this has not been done and hives were moved during the day, check that there is sufficient ventilation between them to avoid suffocation of the bees.
-The load must be well stowed and properly secured. It is also recommended to cover the load with a mesh to prevent bees from escaping.
-Always have a first aid kit equipped with antihistamines and some injectable antidote.
Setting up the hives on the property:
-It is not advisable to inspect the hives on the day of transfer, as they will be more aggressive.
-Always inspect hives in the company of the beekeeper.
-Use safety equipment at all times (suit, gloves)
3) Quality parameters in hives for pollination:
According to Chilean Standard 3255 – 2011, a hive suitable for pollination must meet the following requirements:
-Minimum 8 frames with bees
-Marcos with brood = 3.5
-1.5 frames with open breeding (Annex, image 1).
-2 frames with closed breeding
-Free of pests and diseases
-Number of bees per minute entering through the entrance equal to or greater than 50
4) Installation of the hives on the property:
In the case of cherry trees, the entry of the hives into the orchard is marked by the phenological stage of the white bud. It is at this time that the installation of the hives should begin, since the period between the white bud and the beginning of the flower is relatively short.
Prior to installation:
-The producer is responsible for notifying the beekeeper of the possible date of entry of the hives to the property.
-A map must be provided that specifically indicates the location and number of hives to be used per point. Prefer open areas or roads for the installation of the hives. |
-Ensure that roads are in optimal condition for the passage of vehicles.
-Make sure there are water sources close to the bees. Lack of water causes bees to stop collecting nectar and pollen.
During pollination:
-Check that the hives are not receiving water from irrigation or other nearby sources. If the installation site is humid, it is recommended to ask the beekeeper to change the location of the hive.
-If possible, avoid the passage of agricultural personnel near the beehives.
-Prefer the application of agrochemicals during the afternoons/nights.
-Do not handle bees without the beekeeper's permission.
5) Field control of pollination:
-The distance between groups of hives cannot exceed 200 meters.
– Avoid installing beehives on roads with high pedestrian or vehicular traffic.
-Hives should never be in direct contact with the ground, but should be mounted on pallets, trestles or any structure that isolates them from direct contact with the ground, weeds, attacks by ants, rodents, etc.
-It is preferable to install the hives in dry and sunny places, this way the bees are encouraged to work harder and better.
Targeted Pollen Application
In the absence of pollinators or in the presence of abiotic factors with a negative impact on pollination, a directed pollen application can be made. To do so, we must take the following considerations into account:
-This technique in no way replaces the use of bees or bumblebees.
-It is necessary to identify those sectors of the orchard with problems of setting, in order to densify the number of hives and pollen respectively.
-Regarding storage, pollen must maintain the cold chain to preserve its quality with temperatures ranging from -15ºC to -10ºC.
-Ideally, we should ask our supplier that each dose to be used corresponds to the dose that will be used on the day. In this way, we avoid defrosting pollen that will not be used within the next 24 hours.
- Under no circumstances should you remove the pollen and apply it directly. Ideally, you should gradually raise the temperature. To make it easier, the night before application, if you have the pollen in the freezer of the refrigerator, move it to the lower part (2 to 4ºC). Then, first thing in the morning, you should remove the pollen from the lower part of the refrigerator and keep it at room temperature until you apply it.
-Before applying the product, we need to identify the hives with the highest activity. We should consider that only 50% of the hives are necessary to carry out the application.
During application:
-Start application as soon as the first bees begin to fly in the morning.
-The phenological moment to start the application is with a 20% of the open flowers.
-It is essential to use personal protective equipment such as a veil, gloves and white overalls at all times.
-It is advisable to subdivide the dose recommended by each provider, that is, the amount to be used per day should be applied in 2 or 3 applications.
-In case of unfavorable weather conditions such as heavy fog, drizzle or rain, it is advisable not to apply pollen.
6) Annex. Pollination Protocol Infographic:
Literature
Gil, G. 2012. Fruit Growing: Fruit Production: Fruits from temperate and subtropical climates. UC Editions. Chile.
De la Cuadra Infante, S. and Rodríguez, P. 2019. Manual of pollination of agricultural crops.
Greenpeace (2013). Dangers for pollinators and European agriculture.
Rodrigo, J., Negueroles, J., & Wünsch, A. 2019. Selection of pollinating varieties in cherry. Journal of Fruit Growing 70: 68-71.
Avium Team. November 13, 2020. Flowering and harvest window for the main cherry varieties planted in Chile. Smartecherry. https://smartcherry.cl/infografias/ventana-de-floracion-y-cosecha-para-las-principales-variedades-de-cerezos-plantados-en-chile/ (Table 2).
