# Tree Planting Density and Canopy Position Affect 'Cerasuola' and 'Koroneiki' Olive Oil Quality
## 3 Results and Discussion
### Production and Fruit Quality
Furthermore, to decide the harvest date, many producers use MI in the field, but then the industry uses optical sensors to carry out a preselection of the fruits before oil extraction. Therefore, the results also showed how important the calibration of these sensors is to decrease the possible discrepancies between MI done in the field and the quality of the oil extracted. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{1}{c}{**Cultivar**} & \multicolumn{4}{c}{ ‘**Cerasuola’**} & \multicolumn{4}{c}{ ‘**Koroneiki’**} \\ \hline \hline
**Planting Density** & \multicolumn{2}{c}{**HD**} & \multicolumn{2}{c}{**MD**} & \multicolumn{2}{c}{**HD**} & \multicolumn{2}{c}{**MD**} \\
**Canopy Layer** & **Upper** & **Lower** & **Upper** & **Lower** & **Upper** & **Lower** & **Upper** & **Lower** \\ \hline Fruit yield & 6.82 ab 2 & & 8.03 a & & 4.40 b & & 9.23 a \\ Yield efficiency & 0.23 ab & & 0.26 a & & 0.16 b & & 0.28 a \\ Yield & 6.82 a & & 4.02 b & & 4.40 b & & 4.62 b \\ \% fruit production & 60.7 a & 39.3 c & 61.6 a & 38.4 c & 58.4 ab & 41.6 b & 52.5 abc & 47.5 abc \\ Fruit weight & 1.35 a & 1.35 a & 1.35 a & 1.38 a & 0.87 b & 0.82 b & 0.77 b & 0.79 b \\ Maturity index & 2.56 c & 2.15 d & 3.06 ab & 2.79 bc & 3.18 a & 2.69 b & 2.68 b & 2.54 cd \\ \% black peel & 87.3 ab & 62.7 c & 95.8 a & 79.6 ab & 87.7 ab & 72.6 b & 65.9 b & 71.6 bc \\ Oil yield 3 & 15.7 & 15.4 & 18.5 & 14.9 & 21.2 & 15.6 & 17.3 & 13.1 \\ Moisture content & 49.5 c & 53.7 a & 51.4 bc & 52.5 ab & 49.5 c & 50.5 bc & 49.9 c & 51.7 abc \\ Fat content & 27.4 a & 24.8 d & 27.1 a & 25.5 cd & 27.6 a & 25.8 bcd & 26.9 ab & 26.4 abc \\ \hline \hline \end{tabular}  
* Values followed by the same letters in each row are not significantly different among cultivars and planting densities for the yield parameters, and among cultivars, planting densities and canopy position for fruit quality parameters by [PERSON]’s test at a \(<\) 0.05 (n = 20).
* Only a single oil extraction per treatment combination, no statistical analysis.  
\end{table} 
Table 2: Production and fruit quality of ‘Cerasuola’ and ‘Koroneiki’ olive trees planted at 1000 (HD) and 500 (MD) trees/ha. Production described as fruit yield (kg/tree), yield efficiency (kg cm\({}^{-2}\)), yield (t ha\({}^{-1}\)), percentage of total fruit harvest distributed on the upper and lower layers of the canopy, and oil yield (kg of oil 100 kg\({}^{-1}\) of fruit). Fruit conditions at harvest described by maturity index, percentage of black peel cover (veraison), fresh weight (g), moisture and fat content (g 100 g\({}^{-1}\) of fresh weight). Olives from the upper layers of the canopy produced more oil on average, regardless of cultivar and planting density (Table 2). However, fruit fat content did not follow the same pattern as oil yield, suggesting that other factors (i.e., fruit characteristics) can influence the oil yield even when the same extraction conditions are used [14; 38]. Planting density and canopy position did not affect fruit moisture content of 'Koroneiki'. In contrast, 'Cerasuola' fruit showed higher moisture content in the lower than the upper canopy layers, but only at HD. 'Cerasuola' fruit showed higher fat content at the upper than the lower canopy layers independent of planting density, whereas 'Koroneiki' fruit showed higher values in the upper layers only at HD. These observations agree with findings from previous studies showing that fruits from lower canopy positions accounted for approximately one-fourth of tree fruit production (26%) and oil yield (25.2%) [33], while fruits from the upper canopy layers showed the highest weight, ripening index, and oil content [12; 26; 32]. A possible explanation for a higher oil accumulation is that fruits from upper layers were more exposed to incident light which has been shown to increase the number of oil bodies inside the fruit mesocarp [39].