One strategy, and probably the last one for load regulation, is early fruit thinning, being a very good alternative to improve the size and condition of the cherry. This fruit thinning is recommended to be done when the stone begins its hardening stage, thus it has the advantage that the fruit set is already defined, approximately 20 to 25 days after full flower (DDPF).

For fruit thinning to be effective, it has to end at most 30 to 35 days after full bloom, which is where the fruit cell division process physiologically ends.

“It is a somewhat subjective task, there is no calculation that can be estimated to eliminate or to make the decision to eliminate a % of fruit from the plant. There is a very limited time to do it and although it can be done up to 30 days after full flower, the first 15 days after full flower there is not such a clear expression of what the fruit set is, therefore, about 15 or 20 days after full bloom the fruit set can only be evaluated and technically the time for this work is 10 days later, so there is also the pressure of time that does not allow us to have so much leeway” noted Carlos Tapia, Director Avium SpA.

Both flower thinning and fruit thinning are highly labor-demanding tasks. It is estimated that, depending on the type of orchard, some 70 days per hectare could be considered for this work versus 40 or 50 days per hectare for thinning buds and depending on these three types of load adjustment.

In the case of fruit thinning, the later the slaughter is carried out, the less effect there is on the final characteristics of the fruit and the fewer effects there are on the vegetative characteristics of the plant; however, studies in Chile recognize that any of these treatments carried out good form and based on a technique is effective compared to a control treatment without load regulation.

A work carried out by María Dolores Raffo and Tadeo Ballivian, published by the Fruticultura & Diversificación Magazine Nº 48. EEA Alto Valle in Argentina, based on a research carried out in 2005 on the results of an early thinning trial of fruits in the varieties Lapins and Sweetheart, announced that when evaluating the distribution of sizes within each treatment and variety, it was possible to observe that thinning managed to increase the percentage of fruit in the Jumbo (26.1 to 28 mm) and Premium (greater than 28 mm) categories. .1mm). In the thinned trees, 74% of the fruit was obtained within the Jumbo and Premium categories, while in control only 36% of the fruit fell into said categories. Being the Lapins variety which had better results than Sweetheart, which could be because it has a smaller caliber than Lapins.

The investigation concluded that 94% of the thinned fruit of the Lapins variety presented exportable sizes (greater than 24 mm), while in the control the proportion of exportable fruit was 76%. Regarding the Sweetheart variety, the proportions were 91% for the thinning treatment and 84% for the control.

On the other hand, among the multiple studies carried out in Chile, it has been recognized that although the earliest thinning in the case of buds and in flower are more effective for the improvement of caliber, the thinning of fruits ending prior to 35 DDPF always has an effect positive with respect to the indicator without load regulation.

However, in the event of a deficiency in load regulation management, it is always advisable to intervene in the plant by removing excess fruit, even if it is a decision that may be late in the season.

“The size and final condition of the fruit is mainly determined by seeking an optimal leaf/fruit ratio recognized in the international scientific world as 3-4 leaves per fruit (200 cm2/fruit). If the decision to unload fruit from the plant is late, it is always beneficial to carry it out, since the only way to improve this leaf/fruit ratio is by eliminating the excess fruit.Perhaps this operation will not have a great impact on the final size of the fruit, but it will be positive in the distribution of sugars and nutrients, improving some nutritional indicators and °Brix and internal dry matter content.” added the expert.

Bibliographic references:

• Carlos Tapia-Personal communication.
• Importance of regularizing the fruit load- Agronomy and Forestry UC-Marlenne Araya-Paula Wedeles.
• Regulation of cherry fruit load: a practice that allows increasing export volumes- Fruiting and diversification-Dolores Raffo-Tadeo Ballivian.