Four-year results of growing olives in a super dense composition: Fruit yield and oil quality

This research presents the four-year results (7th-10th of the growing seasosn) of olive (Olea europea L.) cultivation in a super-density plantation established in the experimental plantation of the Center for Fruit and Vegetable Cultivation of the Croatian Agency for Agriculture and Food in Kaštel Štafiliæ (Republic of Croatia). The research includes 5 cultivars: ‘Arbequina IRTA-i18®’, ‘Arbosana-i43®’, ‘Koroneiki-i38®’, ‘Sikitita®’ and ‘Tosca 07®’ and three planting distances of 3.7×1.75; 3.7×1.55 and 3.7×1.35m (=1544, 1744 and 2002 trees/ha). Results are presented for trunk cross-sectional area - TCSA (cm2), fruit yield (kg/tree and t/ha), cumulative yield - CY (kg/tree and t/ha), yield efficiency index -YEI (g/ cm2 TCSA), cumulative yield efficiency index - CYEI (g/cm2 TCSA) and quality of olive oil produced. The cultivars differed significantly in terms of trunk cross-sectional area growth, especially Koroneiki and Tosca. The Koroneiki cultivar, followed by Arbequina, had the highest fruit yield and the highest total yield (kg/tree, t/ha). Increasing the planting distance within the row affected the increase in fruit yield per tree (kg) and the decrease in fruit yield per ha (t). The derived variables YEI and CYEI, where TCSA is used for calculation, show that Arbequina has a significantly higher index influenced by the low value of TCSA. The opposite was true for the Koroneiki variety, which had low YEI and CYEI values due to strong trunk growth, although it had the highest fruit yield (kg/tree and t/ha). In terms of frost damage, Arbosana was the most sensitive, followed by Sikitita, and Tosca was the most resistant. All the olive oils obtained belonged to the extra virgin olive oil category. The highest total phenolic content was measured in the Sikitita and Tosca olive oils (both in 2020). The sensory analyzes of the olive oils revealed special aroma and sensory characteristics for each single-variety olive oil. Further studies are needed, especially in the five to six growing seasons, to collect new results, draw reliable conclusions and evaluate the cultivars in question under our agroecological conditions.