Sweet balance: the effect of Iliostop and Senikant treatments on plant biochemical parameters and yield under field conditions

The trials were conducted during the 2025 season at the orchard of LLC “Pervy Sad,” located in the Republic of Adygea, Teuchezhsky district, Tugurgoy village.

The study was carried out on the Red Delicious variety. Field laboratory equipment for rapid diagnostics was used for regular monitoring.

Phenological stages within нормы: biochemistry as an indicator of orchard health

Throughout the entire apple development cycle—from flowering to fruit ripening—sugar content (Brix) and acidity (pH) remained within optimal agronomic ranges. This is the first and most important indicator of orchard health.

Particular interest lies in the early fruit growth stage (“nut stage” and subsequent development). During this period, Brix values in the fruits were naturally below 10%, which is absolutely normal. Young fruits are active sinks, and sugar and starch accumulation is only beginning.

At the same time, leaf Brix values consistently exceeded 10%, indicating efficient photosynthesis.

Key insight: a high level of assimilates in leaves combined with moderate levels in growing fruits indicates a well-regulated transport of nutrients from source (leaves) to sink (fruits). This balance minimizes risks of:

Development of fungal and bacterial diseases (such as scab, powdery mildew, fire blight), which often thrive in sugar-rich or weakened tissues.
Disorders in fruit development and premature fruit drop, as the tree distributes resources evenly.

Yield: quantitative parity

Harvest results showed high and nearly identical productivity across all variants, confirming proper agronomic practices:

Iliostop: 88.98 t/ha
Senikant: 88.81 t/ha
Control (standard program): 88.96 t/ha

The absence of statistically significant differences indicates that both treatments had no negative impact on yield. All systems demonstrated high performance in quantitative terms.

Fruit quality: biochemical nuances

While total yield was similar, internal fruit quality showed notable differences:

Sugar content (Brix in ripe fruits):
Slightly higher in Iliostop and Senikant variants compared to control—an important factor influencing perceived sweetness.
Phenolic compounds (bioflavonoids, tannins):
Higher levels were observed in treated variants. Phenols act as antioxidants, influence taste (astringency), nutritional value, and contribute to natural protection and storability.
External parameters (size and color):
No significant differences were observed, indicating stable market quality and uniform appearance.

Conclusion and agronomic implications

This study highlights a modern approach to horticulture, where success is defined by the combination of yield, plant health, and biochemical fruit quality.

Key conclusions:

Treatments with Iliostop and Senikant do not disrupt normal plant physiology, as confirmed by stable Brix and pH levels.
These treatments do not significantly affect yield under the given conditions.
The main observed effect is improved fruit quality through increased sugar concentration, enhancing taste characteristics.
Higher phenolic content requires further study to understand its impact on secondary metabolism.

Future research directions

It is advisable to:

study the effects under varying mineral nutrition levels and abiotic stress conditions;
conduct a deeper biochemical analysis (organic acids, vitamins) for a more comprehensive quality assessment.
The trials were conducted during the 2025 season at the orchard of LLC “Pervy Sad,” located in the Republic of Adygea, Teuchezhsky district, Tugurgoy village.
The study was carried out on the Red Delicious variety. Field laboratory equipment for rapid diagnostics was used for regular monitoring.
Phenological stages within нормы: biochemistry as an indicator of orchard health
Throughout the entire apple development cycle—from flowering to fruit ripening—sugar content (Brix) and acidity (pH) remained within optimal agronomic ranges. This is the first and most important indicator of orchard health.
Particular interest lies in the early fruit growth stage (“nut stage” and subsequent development). During this period, Brix values in the fruits were naturally below 10%, which is absolutely normal. Young fruits are active sinks, and sugar and starch accumulation is only beginning.
At the same time, leaf Brix values consistently exceeded 10%, indicating efficient photosynthesis.
Key insight: a high level of assimilates in leaves combined with moderate levels in growing fruits indicates a well-regulated transport of nutrients from source (leaves) to sink (fruits). This balance minimizes risks of:
Development of fungal and bacterial diseases (such as scab, powdery mildew, fire blight), which often thrive in sugar-rich or weakened tissues.
Disorders in fruit development and premature fruit drop, as the tree distributes resources evenly.
Yield: quantitative parity
Harvest results showed high and nearly identical productivity across all variants, confirming proper agronomic practices:
Iliostop: 88.98 t/ha
Senikant: 88.81 t/ha
Control (standard program): 88.96 t/ha
The absence of statistically significant differences indicates that both treatments had no negative impact on yield. All systems demonstrated high performance in quantitative terms.
Fruit quality: biochemical nuances
While total yield was similar, internal fruit quality showed notable differences:
Sugar content (Brix in ripe fruits):
Slightly higher in Iliostop and Senikant variants compared to control—an important factor influencing perceived sweetness.
Phenolic compounds (bioflavonoids, tannins):
Higher levels were observed in treated variants. Phenols act as antioxidants, influence taste (astringency), nutritional value, and contribute to natural protection and storability.
External parameters (size and color):
No significant differences were observed, indicating stable market quality and uniform appearance.
Conclusion and agronomic implications
This study highlights a modern approach to horticulture, where success is defined by the combination of yield, plant health, and biochemical fruit quality.
Key conclusions:
Treatments with Iliostop and Senikant do not disrupt normal plant physiology, as confirmed by stable Brix and pH levels.
These treatments do not significantly affect yield under the given conditions.
The main observed effect is improved fruit quality through increased sugar concentration, enhancing taste characteristics.
Higher phenolic content requires further study to understand its impact on secondary metabolism.
Future research directions
It is advisable to:
study the effects under varying mineral nutrition levels and abiotic stress conditions;
conduct a deeper biochemical analysis (organic acids, vitamins) for a more comprehensive quality assessment.