By: Emilio Martínez, Agricultural Engineer, Avium R&D&i Leader; Nicolás Martínez, IT Engineer, Avium Technical Support; Carlos Tapia, M.Sc., Avium Technical Director.
The analyses (AdYC) seek to determine the flowering potential and thus have fundamental objective data to carry out the different load regulation strategies. They are also an important tool for building the orchard history for each season.
In the ongoing search to objectify strategies and management of crop load regulation, use of dormancy breakers, nutritional programs, etc., qualitative and quantitative analyses of different processes are carried out. It is essential to have as much information as possible inherent to the crop, in order to limit uncertainty regarding indicators that are not managed, such as frost, flowering temperatures, fertilization and fruit setting conditions.
For some years now, Avium's R&D department has been working on data related to cherry bud fertility (AdYC) in different seasons; from this, it has been possible to show that production and fertility are directly related to each other. It is possible to get an idea of this by looking at one of the most planted varieties in the country, such as Lapins, which has had significant growth in recent years and, without a doubt, is the one that largely determines production in each season, reaching a little more than 1/3 of the share in the exported volume according to the 2021-2022 Cherry Yearbook by IQonsulting.
Although the purpose of carrying out this type of analysis (AdYC) is to determine the flowering potential available for all subsequent processes, and thus have fundamental objective data for carrying out the different load regulation strategies, it is also an important tool from which the history of the orchard for each season can be built, creating a powerful database that can be analysed and thus project measures that go towards the optimal production potential for each situation.
There are many factors that affect the floral offer of a given season, where a multifactorial structure can be recognized and must be evaluated in each orchard in particular; among the most important are, among others: A. State of load of the previous year with respect to the condition of the plants. B. Environmental thermal and water characteristics in summer for the flower differentiation process, C. Entry into dormancy or acclimatization, especially due to the climatic quality of the month of April.
For the last twelve seasons, Avium has carried out AdYC, thus responding to the needs of producers, because as previously mentioned, through this tool the load status of the orchard can be initially determined, thereby carrying out any load regulation work to maximize the productive potential of the orchard.
It is important to have the information provided by the analyses, since decisions can be made and actions can be taken in advance, prior to the flower or fruit stages, when regulating the load is more complex and costly. In addition, these analyses allow for a large information base to carry out a more precise study, with the aim of being able to predict some fertility behavior in the future.
In a specific group of cases, for eight seasons, the fertility status of different orchard/variety/rootstock situations has been monitored. This monitoring considers the analysis of flower buds/sapling, flower primordia/bud and their result as the final number of flower primordia/sapling in eight cherry producers in the central area of Chile, in a situation of full production (Producer A to Producer H), comparing the result of this season with that of the previous ones and their percentage of variation with each one. The above is a trend of the analyses of this 2022-23 season, in a generalized way, and the data presented are repetitive to typical orchards. (Table 1 and 2).
After the 2017/18 season, which saw high yields and an estimated average of 8.7 tons/ha of yield, considering plantations older than 4 years (personal data Carlos Tapia), a negative floral supply was observed in the following 2018/19 season. It is evident that after the 2017 “harvest” there has not been fertility at that level, which was a learning experience for the industry, in the sense of looking at and analyzing the available information even more.
The comparisons of floral supply by season show, in general, that there is a marked downward trend in fertility over the last three seasons in most of the varieties and in their different rootstock combinations, this only considering fruiting centers of darts.
In the current season (2022/23), in general terms, fertility rates very similar to those of last season are observed in the Royal Dawn, Bing, Sweetheart and Regina cultivars. However, it is striking that the trend towards low fertility rates in the Santina and Lapins varieties on the Colt rootstock has been consistent, a situation that tends to normalize in the other rootstocks.
It should be noted that the study was carried out with the same data presented in Tables 1 and 2, where, in addition, it is important to point out that the analyses on the Santina and Lapins varieties were only carried out on the Colt rootstock combination.
When comparing the average number of flower primordia from the 2015/16 to the 2021/22 season with respect to the current season (2022/23), a lower fertility in spurs of 20% and 11% can be inferred in Lapins and Santina, respectively. On the other hand, when analyzing Lapins from the current season (2022/23) vs the last one (2021/22), it is possible to see a decrease of around 11% in the floral supply.
The Santina variety also has a fertility of approximately 5% lower than the previous year; it could even be an even lower fertility for this season, reaching a grand average of 12 primordia/fruit centre. Data not published in this exercise showed that a similar downward trend is also generated in the base fertility of one-year-old twigs.
What effects would these aforementioned fertility declines have?
If we consider that Santina and Lapins are probably some of the most planted varieties in Chile in combination with Colt rootstock, these varieties/rootstocks, under normal conditions, i.e. without very adverse climatic effects, adequate applications of dormancy breakers, etc., would be a very good sign for the industry in terms of the quality of fruit that can be produced, obviously with specific load adjustments for each case and fertilization programs appropriate to the productive potential of each unit.
Lapins on Colt rootstock, as fertility tends to decrease, would probably require less intensive regulation techniques; in Santina, while it is not a highly fruit-setting variety (compared to Lapins), load regulation, if it has to be carried out, should not be very complex either.
One of the important conditions that should be highlighted in this “multifactoriality” of optimal needs for obtaining “top” productions is, without a doubt, the percentage of fruit set, being a condition per se of each variety/rootstock combination, and that under this assumption of lower fertility it could even have higher fruit set rates due to an ecological response of the plant, which would not greatly affect the productive potential of these varieties.
The objective of making this information available to the industry is, of course, to be able to provide an objective view of the current state and the productive performance of recent seasons, because, as historians say: "It is necessary to know the past to understand the present and, with it, project the future."
Fountain:
-Tapia. C; Martínez, E., & Labbé, C. (2020). Identification of flowering potential through fertility and bud quality analysis. Mundoagro Magazine.
-Tapia. C. (2018). Preliminary summary of the general situation of the current season in Chile. The post-record production year and its probable consequences. RedAgricola Magazine.
