Fruit trees generally need a certain amount of cold hours annual to regulate their vegetative cycle. The accumulation of cold hours begins in the fall, with the daily reduction in sunlight hours and the drop in temperatures. Little by little, our woody species will slow down its physiology and metabolism to enter winter rest, after a period of accumulation of reserve substances which will serve as the basis for the flowering/budding of the next biological cycle.
Except for some species such as avocado and citrus fruits, which do not need cold to start their biological cycle because they are plants of hot climatesIn fact, they suffer damage from temperatures that are too low (especially avocado), the cold requirements of fruit trees vary according to the species, even the variety.
Whether woody species such as the kiwi or the vine, pome fruit trees such as lto pear or apple, stone fruit trees such as the cherry or the olive tree, nuts such as the almond or pistachio tree, and regardless of the hours of cold, exotic fruit trees such as The citrus and subtropical fruit trees such as avocado, all of them will start a new biological cycle during the next few weeksThe trees will begin to emerge from their dormant state and the sap will begin to move, giving way to flowering or new growth.
Now, global warming and the foreseeable climate change can modify the behavior of fruit species and, years or areas where there is not enough cold accumulation, can cause a sparse or staggered flowering, being able to observe buds in very different phenological states, some may even remain dormant, without sprouting, even falling off in extreme cases, and therefore not producing flowering.
FLOWERING, POLLINATION AND FRUIT SETTING PROCESSES
Particularly important are the flowering, pollination and fruit setting processes.
- Although the flowering It is usually a gradual process within the same plant, its period is relatively short, since the flowers wither and fall if they are not pollinated.
- The weather is of vital importance during the pollination, since low temperatures and precipitation can alter the habits of pollinating insects, reducing their activity; or they can hinder wind pollination, decreasing pollen quality in high humidity conditions. On the other hand, high temperatures can shorten the period of effective pollination or even cause flower abortions.
- Likewise, possible frost or excessively high temperatures can also cause significant damage to the freshly set fruit, causing its loss.
For pollination to take place, the pollen transfer from the anther of the flower to the stigma of another flower (alogamy) or from the same flower (autogamy), in the case of hermaphrodite and self-compatible flowers. This transfer can be carried out by the wind (anemophilous) or by pollinating insects (entomophilous), depending on the fruit species. Once the pollen grain reaches the receptive stigma of a flower, it must germinate and the pollen tube must travel the path that leads from the stigma to the interior of the embryo sac, where the fertilization giving rise to the future seed and with it, to the conversion of the flower into fruit.
After pollination, fruit set occurs. The influence of seeds on fruit growth is regulated by hormones., mainly auxins, gibberellins and cytokinins, whose levels decrease as the seeds mature.
It should be noted that some fruit species, such as Citrus, can develop fruit without the flowers having been previously pollinated and fertilized. This fruiting, known as parthenocarpic, produces fruits that are characterized by the absence of seeds. The parthenocarpic fruits They contain auxins and cytokinins in lower concentrations than the seeded fruits of the same species, and gibberellins are practically absent. They are more susceptible to natural decay and, to
to obtain an adequate level of production, it is It is essential to keep plants in optimal nutritional statusIn some cases, this parthenocarpy is induced by the application of gibberellins, which induce an increase in the content of endogenous auxins in the ovary of an unpollinated flower and also cause fruit growth in the absence of fertilization.
NUTRITIONAL AND HEALTH STATUS OF THE TREE
The nutritional and health status of the tree influences all these processes.. The absence of a post-harvest fertilizer plan after the previous campaign, it can negatively affect flowering. Not restoring certain nutrients After the fruit tree's productive period, it has a direct influence on the accumulation of reserve substances in the tree's various organs. These reserve substances will be the sole source of supplies during the exit from winter rest of the crop, until, once the first vegetative organs have developed, photosynthesis slowly and gradually provides the nutrients necessary for the normal physiological and metabolic functioning of our fruit species. In general, cultivation techniques that promote flower growth and development or limit competition between them (pruning, sanitary control, early irrigation, good nutrition, etc.) promote the fruit-bearing capacity of flowers.
Focusing on the nutritional aspect, Correct application of fertilizers before and during flowering and during fruit setting is essential to maintain an adequate number of fruits per tree..
At the level of macronutrients, nitrogen (its application should be done during post-harvest) plays a fundamental role, increasing the longevity of eggs and therefore, increasing the period of effective pollination; the Calcium, on the other hand, positively influences the germination of the pollen grain, so that as long as germination occurs normally, the faster the pollen tube growth will begin.
The microelements They play an essential role in flowering. Among them, and due to their level of consumption, the most important are el boron, zinc and manganeseThey are related to flowering, fruit set and number of fruits, and Its deficiency in the plant causes physiological disorders and reduces the number of fruits per tree..
El boron It is essential for the main physiological processes of plants, such as cell division and growth. However, this micronutrient also plays a key role in pollination and fruit set. During these stages, boron increases the viability of pollen grains. It also participates in the transport of sugars, carbohydrates and potassium, in nitrogen metabolism, in the formation of proteins and in the regulation of hormone levels. Among the symptoms of the deficiency Boron side effects include inhibition of root growth and development, cessation of cell division in stems and young leaves, short internodes, dry shoots, deformations, and of course, Low pollen viability and flower abortion and dropIts deficiency can negatively impact a wide variety of crops, causing triple buds in citrus fruits, small, gum-like, and mummified fruit; flower drop in vineyards; gradual death at the apical growth points; dried branches and apical meristems in olive trees, etc.
El zinc It intervenes directly in the synthesis of some amino acids, although its most relevant function in plants is activation of numerous enzymes, highlighting the synthesis of auxins. Therefore, participate in the production of growth regulators responsible for internode elongation and chloroplast development. It is also used by the plant to form chlorophylls and some carbohydrates, and it improves resistance to low temperatures. Its deficiency significantly reduces growth and productive potential..
El manganese It is related to photosynthesis, the efficient use of nitrogen, protein metabolism, and enzyme activation. It acts on carbohydrate and fatty acid metabolism, phosphorylation reactions, and the formation of nucleic acids (DNA and RNA), in addition to intervening in the photolysis of water in photosynthesis, as well as in the synthesis of sucrose in the plant and in the formation of proteins. influences in the processes of pollen germination, growth of the pollen tube and cell elongation, in addition to enhancing the plant's resistance to biotic stresses. Severe and persistent manganese deficiencies reduce growth and productivity.
En Cultivator we have a wide catalogue of deficiency correctors focused on covering the nutritional needs described for the flowering and fruit set processes in fruit trees:
Cultifort Calcium, is a liquid fertilizer with a high calcium content in the form of lignosulfonate, in combination with organic matter and carbohydrates, which gives it a high penetration power and ease of assimilation by the plant.
Cultiboro Plus, It is a liquid formulation and organic farming of boron complexed with monoethanolamine containing reducing sugars, forming a complex to improve its assimilation and transport by the plant. In addition, it is chlorine-free.
Manzifort, It is a liquid formulation with high richness in zinc and manganese chelated with EDTA, polycarboxylic acids and reducing sugars, and is also certified for use in ecological agriculture. Ease of application, speed of action and effectiveness, are the main characteristics achieved with this simultaneous zinc and manganese corrector, since they are deficiencies that are usually associated in many crops, making it advisable to control them together.
En Cultivator We are also manufacturers of a wide range of biostimulantsThe use of biostimulants in agriculture has direct benefits. They help to better manage extreme situations and achieve crop excellence. They are becoming more and more common every day. valued and Used to protect and make production profitable in stressful situations or to help the crop at critical moments of its development.
Fruit trees have other needs that are complementary and equally important to those of fertilizers. This is where biostimulants come into play. Its effect has a positive impact on the yield and quality of the harvest. as well as in the “resilience” of the tree subjected to different types of stress, providing the resilience and recovery capacity to extreme situations. In addition, in specific phenological phases such as flowering, fruit set, fruit fattening or ripening, plants may have a significant increase in needs. It is in these states that it is necessary act to cover metabolic requirements with the help of biostimulants.
In the case at hand, the flowering and fruit setting, BVC 2021 would be the recommended biostimulant. It is a plant metabolic activator even under adverse conditions (temperature, lighting, wind, etc.), based on amino acids and algae in emulsion, also containing nitrogen, potassium and reducing sugars. It increases the rate of photosynthesis, improves the assimilation and translocation of nutrients, increases the synthesis of amino acids, peptides and proteins. It promotes the onset of plant physiological activity and exerts a multifactorial control in flowering. And now its formula has been improved by the CULTITEK Activating Biotechnology, further reinforcing its effect on the chlorophyll biosynthesis and photosynthetic activity.
And for those deciduous fruit species or fruit trees with flowering problems, Foliquino is ours star biostimulant. It is an energy-rich biostimulant that, thanks to its formulation with organic acids, makes it assimilated by leaves, branches or woody parts and by the root system. Its operation is based on the potent systemic action of aluminum lignosulfonate, whose mobilityBoth upward , the falling inside the plant, it helps to balance the aerial part and the root system, improving the sprouting of dormant buds and therefore, achieving a flowering of greater quantity and quality. Product certified for use in organic farming.
BVC 2021's partnership with Foliquino brings remarkable synergy. Improves the product's performance as a stimulant and against the conditions for which it is indicated.