Postharvest handling in temperate climate fruit trees

Alberto Ormazábal Araya.

Regional Leader Innovak Global Chile

Innovak Global International Technical Support

For deciduous fruit trees that develop in temperate climates with a winter recess period, the sugars and amino acids from the reserve play an important role in the growth and development of the first structures that support flowering and in the flowering itself. . There is a complex process from flower induction to fruit maturity, which takes two growing seasons. Until very recently, sugars were seen only as sources of energy during the formation of reproductive structures from flower induction during the summer of the first year, to fl owing during the following spring. These sugars that are used in the development of reproductive structures are supplied by those stored in permanent structures, such as roots, trunk and branches, or by photosynthesis in leaves or inflorescences, depending on the stage of development.

Fig 1: Fluctuation in the levels of compounds derived from the reserve and photosynthesis during the annual cycle in a temperate fruit tree.

In the formation of flowers, especially in meiosis, the supply of reserves is very important because it determines the expression of the differentiation of the tissues that occurs during winter recess, and that corresponds throughout the plant to the transition between the remobilization of reserves from organs of accumulation until the structures that support production manage to pass the photosynthetic compensation point.

Deficiencies in the accumulation of reserves during the previous year cause failures in flower development and in flowers, while the alteration of photosynthetic sources affects the formation of flowers and fruit development during the same year. In particular, the unavailability of sugars in flowers in female meiosis caused by environmental or physiological factors can lead to drastic flower abortion.

In addition to energy, sugars also play roles as regulators of gene expression and as signal molecules that may be involved in responses to stress. The same occurs with nitrogen, which is associated with amino acids that are also mobilized from reserves to sink points to constitute the first growths of the season. (Fig.2).

Fig 2. From budding to flowering, starches and nitrogen (amino acids) are mobilized from reserves to support first season growth.

If we analyze the theoretical behavior of root apex growth during the deciduous fruit season in temperate climates with winter recess, we can observe that there are two moments in which there is an increase in the root growth rate and therefore a greater absorption capacity of nutrients from the soil solution. The first occurs at the beginning of the season driven by the auxin activity of the shoots, and the second during the months where the postharvest stage will be developing. (Fig. 3).

Fig. 3: Evolution of the growth rates of the structures that make up a deciduous fruit tree developing in a temperate climate system with winter recess. Br: Sprouting, Ant: Antésis, Pt: Pinta, Cos: Harvest. Adapted from Mullins et al, 1992.

As we had pointed out, this is the opportunity to be able to incorporate nutrients into the plant, associated with the growth flow of new roots, and the fact that only in the first segments (the most apical) of the growing roots (active) are those that they have the ability to absorb nutrients, the rest just water.

Innovative Concept

The seven important points of postharvest in temperate climate fruit trees
For postharvest work we have to take into account the following points:

1. Not all years are the same and plants do not respond linearly to production factors: What the plant experienced during the season in terms of environmental growth conditions (light, temperature and humidity and soil, etc.); availability of nutrients (which were in the soil and those provided in the nutrition program); and the moment in which these were present during its phenological development, are relevant factors that determine the quantity, form, place for the synthesis, use, distribution and storage of carbohydrates and amino acids that will be used immediately, or will be part of the reserves of short-term use (both during the period of use) or long-term use of the plant (important towards the winter break and to be used the following season).

2. Change in the hormonal balance: The decrease in the length of the day, which brings a gradual decrease in temperatures, added to the change in the use flows that were strongly driven by the presence of the fruits before harvest and Before due to vegetative growth, today they exert a hormonal imbalance that translates into a new regrowth of the roots with the consequent synthesis of cytokinins, which will act opposing the maturation and senescence effect of ethylene and ABA (abscisic acid) prolonging for a time plus the photosynthesizing activity of the cup.

3. Maintain the supply of photosynthates, a good investment of resources: The resources that were produced during the season (sugars and proteins) were invested in the structures necessary for the operation of the plant: shoots, leaves, roots, fruits, structures permanent (wood in the crown and in the structural roots), in such a way that accumulation and consumption vary according to the phenological needs of each structure in the plant (activity of sources and sinks). After the harvest and at the end of the season, the supply needs for shoots and obviously the fruits no longer exist, so the resources produced from now on are used for their immediate use (basal and functional metabolism) and for the synthesis of reserve compounds. For this reason the maintenance of a photosynthetically active crown during these months (postharvest) is important to maintain the supply of photosynthates. It is important to bear in mind that activation does not imply waste, that is, it does not promote a strong bud sprouting (expenditure of undifferentiated lateral buds) but rather produces an effect opposite to the senescence of the hormones ethylene and ABA, through their antagonists: cytokinins, auxins, and gibberellins. Being the cytokinins contained in Selecto XL, the ones with the greatest antagonistic effect we could have.

4. The accumulation of reserve compounds: Vegetative buds can only develop if there is an adequate supply of soluble carbohydrates, derived from the mobilization of reserves from other parts of the tree. These act as an important sink and its ability to sprout is strongly conditioned by its availability of carbohydrates and amino acids during the period of accumulation of reserves and the winter cold during the break, but also to the presence of free cytokinin in it. In this way, plants accumulate reserves (carbohydrates, amino acids and proteins) during the season in periods when production exceeds consumption, which today occurs only if the glass still has a good photosynthesizing capacity (above its compensation point, it is say donor) and there is root activity that supports it in terms of the supply of water, nutrients and hormones

5. Levels of N-organic and its importance during the beginning of the season: There is a linear correlation between the levels of nitrogen reserves in winter and the growths in the following spring. However, the nitrogen dependence of the new growths (reserve or applied) is conditioned to its availability both in the fall and in the following spring. In this way, sufficient levels of N-organic accumulated as a reserve respond better to recess breakers (hydrogenated cyanamide, Vernum or others) and even without them, buds with high reserve levels require less cold for good sprouting.

6. High levels of cytokinins in the buds: It must be remembered that we will need to ensure that in postharvest we have a real root activity that can maintain the photosynthetic functionality of the plants and thus allow a better accumulation of carbohydrates. In addition to absorbing the nutrients necessary for the reserve structures, they must synthesize the necessary cytokinins for robust bud differentiation.

It has been observed that the concentration of reserve sugars decreases in darts and twigs as the fruits mature (reduction by accumulation and use) and once harvested they increase together with the levels of free cytokinin in the buds. In addition, low concentrations of reserve sugars in years of high fruit load are associated with low levels of free cytokinins in the buds, thus conditioning one year off in the productive alternation (anerism).

7. Importance of maintaining postharvest root activity: It is important to maintain active roots and better yet new lateralizations in the postharvest stage, since the youngest portions of the root (1 to 4 days) are those with high respiratory activity and hence the ability to absorb nutrients. This respiratory activity in the roots requires favorable environmental conditions such as adequate humidity and oxygenation of the soil. That is why we must not forget that in winter we must maintain moisture in the soil, if necessary by applying irrigation. (Be careful with winters that can have a dry and warm start with abundant rains towards the end of the season).

The above makes us think that the occurrence or not of these root growth fluxes in postharvest are determined by different factors influenced by the nutritional status and the resulting hormonal balance, which explains the heterogeneity of responses and activities of the roots from year to year; and the occurrence in some fruit orchards of its premature decay. We have to take into account in the winter break stage, around 75% of the nitrogen and 80% of the starches of the plant is stored in the roots.

This reaffirms the need to ensure the occurrence of good postharvest root activity through the use of the root hormone activator Radigrow.

Recommendation for postharvest root preparation

  • Apply via soil: 2 to 3 L / ha of Radigrow + 5 to 10 L / ha of Promesol Ca.
  • Opportunity: 10 to 20 days after the harvest (depending on the fruit tree).

Recommendation for the correction of low boron and / or zinc levels.

  • Apply via foliar: 1 to 3 L / ha of Proborate and / or 1 to 2 L / ha of Proquelate Zn.

Referencias

Cheng, L., G. Xia and T. Bates. 2004b. Growth and fruiting of young ‘Concord’ grapevines in relation to reserve nitrogen and carbohydrates. Journal of American Society for Horticultural Science 129: 660-666.

Lebon, G & Wojnarowiez, G & Holzapfel, Bruno & Florence, Fontaine & Vaillant-Gaveau, Nathalie & Clément, Christophe. (2008). Sugars and flowering in the grapevine (Vitis vinifera L.). Journal of experimental botany. 59. 2565-78. 10.1093/jxb/ern135.

Mullins, M.G., Bouquet, A., Williams, L.E., 1992. Biology of the grapevine. Cambridge University Press.

Williams, L.E. 1991. Vine nitrogen requirements – Utilization of N sources from soils, fertilizers, and reserves. Proceedings of the International Symposium on Nitrogen in Grapes and Wine. The American Society for Enology and Viticulture. pp. 62-66.

ECCA Solutions

Biostimulant for Fruit Lashing and Size

WHAT DOES IT DO?

Increases the proportion of harvestable fruit and its economic value by fruit size.

HOW DOES IT WORK?

The ECCA Carboxy® Acids in this formulation induce phosphoinositide biosynthesis, increasing the response amplification capacity of the fruiting tissue. It also includes the nutritional support necessary for the adequate stimulation response for the tie and the filling of the fruits.

BENEFITS

  • Avoid excessive drop in fruiting by increasing the proportion of harvestable fruits.
    • It allows to obtain a higher proportion of fruits of excellent size and commercial value.
    • Uniformizes the size of fruits and grains.
    • Improves the capacity of the plant to generate branches (arm) and fructifications.
    • Strengthens shoot growth.

Recommendation for foliar preparation after harvest

Foliar application 2 to 3 L / ha of Selecto XL can be repeated 10 to 20 dd.

Note: only in those cases where it is justified to accompany the application of Selecto with urea 10-20 kg / ha. Objective: arginine and protein reserves in wood.

Global Notes

Potato Congress

Icca, Peru hosted the 2018 Innovak Global International Potato Congress.

Guests from Mexico, Colombia and Peru attended the congress where international exhibitors updated the guests on Regulation of Root Dynamics and Biostimulation.

In addition to talks, there was a demonstration of RDR in a demonstration plot, where the commercial team was able to demonstrate the effectiveness of our products in Papa. Innovak carried out very interesting practices of our products in cultivation that reinforce the four pillars on which RDR is based.

All attendees lived together and had the opportunity to exchange their experiences with the management of the Innovak Global line.

Berries Congress

During the month of October, Coquimbo, Chile hosted the 2018 Innovak Global International Berries Congress, where important producers from the United States, Chile, Mexico, Peru and Colombia met for three days to update themselves on technological issues and solutions that Innovak toast for berries.

Experiences in the field, Metagenomics and its effects on crops, Physiology and hormonal activity of Blueberries were the topics that were discussed in the conferences given at the event.

In addition to this, the theory of the lectures was specified with the practice of the Regulation of Radicular Dynamics and our line of biostimulants in a field trip.

The coexistence between the guests, the Innovak team and exhibitors was present during the three days of the event and in tourist tours such as the Mamayuca Observatory and Viña Tabalí.

Food Expo

Once again Innovak Global was present at the most important national expo of the year Expo Agroalimentaria 2018 that took place in Irapuato, Gto, Mexico in order to provide information to know the latest in agricultural production systems and commercialization of products for the sector.

The Innovak team distinguished itself by serving visitors at its stand, the strawberry plot in conjunction with the Irapuato Strawberry Product System and in the 4 hectares of blueberries treated with our line of biostimulants and RDR technology.

Photography Contest

For the fourth consecutive year, Innovak Global launched its call for the photography contest in constant innovation for the members of the company.

Creativity, effort and a lot of talent led the jury to choose 8 winners from 50 participants.

Innovak Global recognizes and congratulates all the participants of this contest, for their valuable effort in capturing the benefits of our products in photographs.