The aim of this study was to study the impact of crop load on the yield and grape quality of ‘Merlot’ and ‘Vranac’ (Vitis vinifera L.) in Trebinje vineyard. The crop load levels studied in this trial were 9 buds (V1) and 12 buds (V2) per vine at each variety trained on Lenz-Moser bilateral cordon system. The impact was determined by measurements of yield per vine and grape quality characterized by the contents of total soluble solids, titratable acidity, total phenolics, total flavonoids and by total antioxidant capacity. The measured parameters of grape quality of ‘Merlot’ and ‘Vranac’ were not influenced significantly by crop load levels. V2, compared to the V1, showed the potential for increasing grape yield only for Merlot variety under experimental conditions. The results of this study also showed a positive correlation between total phenolics/flavonoids and total antioxidant capacity of grape berries in both varieties, regardless of crop loads applied.

Different agro-technical measures are used in growing apples and fruit crops in general in an attempt to increase the rate of photosynthesis and, hence, both the quantitative and qualitative value of the fruit. Very rapid and effective results in terms of an increase in the above parameters can be achieved through adequate fertilization adapted to plant requirements. Fertilization can substantially alter and disrupt the course of plant development if fertilizers are inadequately applied, regardless of the adequately pre-determined plant nutrient requirements. The objective of this study was to evaluate the effect of four different types of fertilization on the pigment and antioxidant content of apple cv. Idared (Malus domestica cv. Idared) grown in orchards in the municipality of Gradacac. The results obtained show that fertigation and foliar fertilization induced the statistically highest increase in the test parameters. These types of fertilization, if adequately employed, provide nutrition to plants according to their requirements at a specific phenostage, leading to increased yields and enhanced fruit quality, and indirectly reducing nutrient leaching from soils – a frequent accompanying manifestation of other fertilization types.