1. BACKGROUND

Producers of deciduous fruit trees at the European level continue to face campaigns evaluated as negative due to the lack of chilling hours for most of these species, not reaching a minimum to ensure proper hormonal regulation that guarantees normalized and homogenized processes of flowering and fruiting.

It should be noted that for proper self-regulation by the crop, a cumulative total of hours below 7 degrees Celsius must be obtained within a range between the months of December and mid-February, or by a more common practice, counting these hours from the time the trees shed their first leaves until the well-known phenological phase known as swollen bud.

However, the panorama presented to us this campaign includes frequent daytime temperatures of 20°C and not excessively low nighttime temperatures in the majority of the Iberian territory.

 

2. DERIVATIVES OF THE CURRENT SITUATION

The lack of chill hours leads to the occurrence of so-called “blind buds,” causing partial, irregular, and non-uniform sprouting, making efficient crop management challenging. Buds formed in very hot springs with low relative humidity will require a more extended rest period, potentially increased by up to 50%.

Delay in sprouting, especially in vegetative organs (lateral buds). High sprouting of terminal buds, with greater vigor and final growth compared to the rest. Excessive vegetative growth. Delay in tree production onset. Delay and prolongation of the flowering period, early shoots vs. annual twigs (later). Floral buds open before vegetative ones. Imbalance in reserves (early fruit drop due to nutrient deficiency). In young trees, there may be less bud sprouting, but the ones that emerge will be more vigorous, causing a delay in plant precocity. In species like peach, bud drop has been reported. Small and low-quality fruits. Irregular ripening. Altered storage potential.

 

3. UNDERSTANDING PROCESSES DERIVED FROM SELF-REGULATION BASED ON TEMPERATURE AND LIGHT

In this regard, there are formulations aimed at alleviating the lack of chill hours by influencing the so-called ENDODORMANCY, controlled by inherent bud conditions that prevent it from sprouting (rest), depending on exogenous or environmental signals of a standardized cycle. The phytochrome (p730) serves as a biological light switch, and the characteristic thermoperiod of the year is the basis for this process.

Regarding this, an increase in short days has a negative effect on the synthesis of phytochrome P730, located in the chloroplasts of the leaves. A reduction in this leads to a decrease in growth processes. Reduced growth results in the synthesis of auxins, cytokinins, and GA.

As for the thermoperiod, among external signals, it is the most important in deciduous species in our latitudes. The drop in temperatures at the beginning of autumn leads to a generalized reduction in plant metabolism, summarized as: reduction in enzymatic activity / reduction in respiratory intensity / reduction in photosynthetic activity / reduction in transpirational activity (influence of ABA) / decrease in water and nutrient solution absorption rate / low assimilation of nitrogenous substances and low assimilation of P and K.

Hormonally, there is a reduction in auxin, cytokinin, and GA synthesis, tipping the balance in favor of Ethylene and ABA, triggering senescence processes (leaf abscission, lower respiratory rate, metabolism paralysis, etc.). ABA, as in seeds, keeps buds dormant, protecting them from low temperatures until sprouting conditions are suitable.

  1. FUNCTIONAL BASES OF A COLD HOURS COMPENSATOR

We are aware, as explained earlier, that although dormancy is related to environmental conditions, this phenomenon is of endogenous origin, meaning it is intimately connected to a progressive decrease in growth promoters (auxins, gibberellins, and cytokinins) and a progressive increase in inhibitors (abscisic acid). When the concentration of these plant hormones is reversed, meaning when the endogenous content of promoters increases and the level of inhibitors decreases, dormancy is broken, and the bud sprouts. In this sense, the use of artificial substances known as “cold compensators” or currently “bud stimulators” aims to activate the enzymatic reactions involved in the synthesis of plant growth hormones that promote bud sprouting.

The function of a cold hours compensator is to stimulate chemical reactions in the buds that did not occur naturally due to the lack of low temperatures. The effect of compensators is not generalized throughout the tree since each bud typically has a different resting condition, depending on its position (terminal or lateral) and type (vegetative or floral). The application of these chemicals serves three purposes: accelerate flowering, standardize flowering, and stimulate bud sprouting.

 

  1. CULTIFORT SOLUTIONS

From CULTIFORT, a strategy with proven results is offered with a compensating effect for cold hours or bud-stimulating effect.

This strategy is based on the combination of BVC 2021 and FASKOLOR.

 

BVC 2021

 

 

 

 

 

 

 

 

 

 

 

BVC 2021 is a biostimulant with a combined action of specifically selected amino acids, nitrogen, and reducing sugars to exert a versatile influence on different phenological phases, promoting the self-synthesis of natural substances (proteins, peptides, amino acids, phytohormones such as cytokinins) and improving the profiles of active substances (polyphenols, essential oils, alkaloids, vitamins…).

Its cytokinin-promoting activity will enhance, among other variables:

  1. Promotion of the onset of plant physiological activity.
  2. Stimulation of leaf and flower formation.
  3. Improvement in fruit quality.
  4. Promotion of precocity in the maturation phase.
  5. Increased resistance to low temperatures and adverse weather conditions, a key factor for flowering and fruiting phenologies.

On the other hand, FASKOLOR incorporates organic acids and peptidic complexes that exert a physiological, non-hormonal action on the crop. It acts directly on the chloroplast, maintaining the structure and function of thylakoidal membranes and regulating the level of oxidation products and redox balances.

  1. RESULTS OF THE PROPOSED STRATEGY.

Number of applications: 3 spread applications.

  • First application at pink bud stage (BVC 2021 foliar + FASKOLOR root).
  • Second application between 75-85% open flower (BVC 2021 foliar + FASKOLOR root).
  • Third application at the beginning of fruit color change (BVC 2021 foliar + FASKOLOR root).

MELOCOTÓN

 

Dosage: 300 cc/hL (3 foliar applications) of BVC 2021 + 5 L/ha of FASKOLOR as indicated (3 root applications).

Producer’s Management Uniformity in Sprouting

  • BVC 2021 provides the buds with the necessary metabolites to overcome dormancy, ensuring their uniform opening along the branches and complete activation. The product works on wood and penetrates into the interior of the dormant bud, transporting the nutrients that activate enzymatic processes and create the necessary energy for meristematic tissues to sprout and develop uniformly and regularly.
  • FASKOLOR offers uniform ripening and size uniformity: the homogeneous opening of buds promotes even and uniform fruit ripening by reducing apical dominance.
  • Increased profitability: the applied strategy yields results where fruits reach commercial maturity earlier, with larger size, better coloring, and optimal organoleptic qualities. Improved productivity and fruit quality.
  • Labor cost savings in harvesting. Its use allows for cost reduction and increased harvest profitability due to more clustered harvesting.
  • Return on investment per hectare considering variables such as early maturity and increased productivity, in terms of the percentage of set fruit and total weight, +- 9%.