One of the most important groups of bioactive substances in apples are antioxidants, which have a health-preserving effect. The amount of these compounds varies not only during the ripening of the apple fruit, but also continuously during post-harvest storage. A growing group of health-conscious consumers are looking for apple varieties with a nutritional value that satisfies their needs. In the scope of our research, we examined 5 apple varieties originating from the Derecske horticultural site of KITE cPlc. in 2016. The plantation was planted to be suitable for intensive apple production. Samples were collected at the time of maturity (August-October) of the given variety. The 5 examined apple varieties (Gaia, Isaaq, Modí, Smeralda and Fujion) are all resistant to apple scab (fungal disease caused by Venturia inaequalis). The 2-month storage experiment was conducted at 16–17 °C, which had an aggressive effect on our stored apples. Total polyphenol (TPC) and flavonoid (TFC) content as well as FRAP values of the apples were measured. Measurements were taken immediately after harvest and after 1 and 2 months of storage. Our results were evaluated by using the IBM SPSS Statistics 20 software. Our aim was to compare the antioxidant results of 5 scab-resistant apple varieties, which change continuously during storage. The antioxidant content of our apple varieties increased during 2 months storage. The best result was achieved by the Modí apple variety (FRAP: 467.32 mg/100g; TFC: 317.76 mg/100g; TPC: 1771.97 mg/100g). Consumers may want to consume apples stored for a longer period of time if they are to absorb large amounts of antioxidants.

Polyphenols with antioxidant compounds represent an important group of bioactive substances in apple production. The objectives of this study were firstly to measure four parameters of antioxidant capacity (AC) and polyphenol content (AC-FRAP (Ferric Reducing Ability of Plasma), AC-DPPH (2,2-diphenyl-1-picrylhydrol), AC-TEAC (Trolox Equivalent Antioxidant Capacity) and total polyphenol content (TPC)) of four scab-resistant apple cultivars (‘Fujion’, ‘Gaia’, ‘Isaaq’ and ‘Smeralda’) using six extraction methods (water control, pectinase, two approaches using ethanol (EtOH-1 and EtOH-2), methanol (MetOH) and methanol + acetone (MetOH + Acetone), and secondly to provide intercorrelations between antioxidant and polyphenol contents of the four resistant apple cultivars under the six extraction methods. Analysis of variance on the four parameters showed a significant (p = 0.05) effect for extraction methods and cultivars. TPC showed the highest values among the four parameters in all extraction methods and cultivars compared to the other three measurements. The pectinase extraction method showed the highest TPC values for the four cultivars. The EtOH-2 extraction method showed the lowest AC-FRAP value for all cultivars. The EtOH-2 extraction method showed the highest AC-DPPH values, whereas the control method showed the lowest values for the four cultivars. The AC-TEAC values were generally the lowest, ranging between 10.8 and 40.5 mg TE 100 g−1 dry matter, and they showed various effects on extraction methods and cultivars. Correlation and regression analyses of 36 pair-variables showed that two pair-variables (TPC vs. AC-FRAP and AC-TEAC vs. AC-DPPH) were significant for all of the six extraction methods and for all cultivars. In conclusion, the extraction method using pectinase enzyme provided the most stable yield of polyphenol content from apple flesh, as confirmed by the examination of four scab-resistant apple cultivars.

Plant nutrition significantly influences yield and fruit quality in fruit orchards. In this three-year study (2016–2018), different fertilizer treatments were compared in an intensive sweet cherry orchard. Trees of cultivar ‘Carmen’ were grafted on Prunus mahaleb ‘Cema’ rootstock, and were trained to free spindle. For NP, NPK and NPKMg treatments, yield ranged between 11.8 and 16.6 kg/tree in the three years, while the yield was 9.1 kg/tree on the control trees. Crop load (fruit amount calculated to the trunk thickness) was 151–166 g cm-2 for fertilized trees, while it was 120 g cm-2 on the untreated trees. Fruit sizes of fertilized trees reached 30 mm in 2018, while the fruit sizes of control trees were smaller with 2.5 mm. Water-soluble dry matter content (%) of the fertilized trees was lower in 2016 and 2017, but higher in 2018 compared to the control plots. In 2017 and 2018, fertilizer treatments resulted in an increase of the content of phosphorus (16–70%), potassium (4–22%) and magnesium (12–43%) in the fruits compared to control plots.

Of the different physical features of fruits, one important quality feature is flesh hardness. This is an important parameter to be considered when selling fresh apples, for the manufacturing industry and when entering into storage. In our research, we examined 7 apple varieties, in 2016 and 2017, from the establishment of KITE Zrt. in Derecske and the Horticultural Experimentation Site of Pallag (Pallagi Kertészeti Kísérleti Telep). The plantations took place in accordance with intensive apple production. In both years, samples were collected at the time ripening of the given apple variety. Of the examined apple varieties, 5 of them are resistant to scab (Gaia, Isaaq, Modí, Smeralda, Fujion), 1 is not resistant (Golden Reinders) and 1 (Pinova) is moderately susceptible to scab. The scab resistant apple varieties were correlated to the non-resistant Golden Reinders. Flesh firmness was measured with a fruit penetrometer in each of the seven apple varieties. In the first year a two-month storage experiment was carried out, where the flash firmness after harvest, and after one-month and two-month storage was measured. The results were assessed with the help of the IBM SPSS Statistics 20 program. The goal is to compare the apple varieties based on their flesh firmness, in particular with regard to the resistant varieties. The Isaaq 8.81–8.82 N/cm2 , the Modí 9.18–9.59 N/cm2 and the Fujion 8.66–9.13 N/cm2 , all of which are scab resistant apple varieties, showed a significant initial flesh firmness. During storage, the Pinova apple variety flesh firmness changed the most favourably.

This two-year-study was aimed to provide results on the effect of nitrogen, phosphorus, potassium and magnesium fertilizer treatments (control, NP, NPK, NPKMg) on vegetative and generative features of the sweet cherry cultivar ‘Carmen’. Examinations were performed in an orchard planted in 2012 on Prunus mahaleb rootstock with spacing of 5 x 2.5 m. All treatments improved the vegetative features of the sweet cherry trees in both years of 2016 and 2017. Fertilizer treated trees increased trunk cross section area (TCSA) with 51.3-63.1%, while control trees showed 48.3% trunk growth increase. Yields of control trees were lower in both years (5.9-7.2 kg/tree), than that of the fertilized trees (7.8-11.3 kg/tree). Treatments also increased the phosphorus (16-22%), magnesium (12-20%) and potassium content (3.5-18%) of the fruits compared to control treatments.