## 2 Results and Discussion  
Oils from the Core-36 cultivar collection exhibited a high level of variability regarding the volatile compound contents (Figure 1 and Table 2). Most of the VOO volatile compounds are synthetized through the LOX pathway [3], and they may be classified into different groups regarding chain length (C6 and C5), the polyunsaturated fatty acid origin (LnA or LA), and the origin of the esters (LOX esters). Additionally, a group of compounds, derived from amino acids, carrying a branched-chain (BC) structure and a terpene, seem also to contribute significantly to the volatile fraction of the oils. Only hand-picked, sound fruits and mild operation conditions were used in this study; as a consequence the oils were devoid of compounds responsible for the off-flavors, such as carboxylic acids or aliphatic C8-C11 carbonyls and alcohols [15]. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Cultivar** & **WOGC Reference** & **Country** & **Mediterranean Geographical Area** \\ \hline Klon-14-1812 & 1812 & Albania & Centre \\ Koroneiki & 218 & Greece & Centre \\ Leccino & 82 & Italy & Centre \\ Llumeta & 226 & Spain & West \\ Maarri & 1125 & Syria & East \\ Majiol-1013 & 1013 & Syria & East \\ Majiol-152 & 152 & Syria & East \\ Manzanilla de Huercal Overa & 757 & Spain & West \\ Manzanilla de Sevilla & 21 & Spain & West \\ Mari & 1143 & Iran & East \\ Masticolis & 345 & Greece & Centre \\ Maveya & 699 & Greece & Centre \\ Megaritiki & 108 & Greece & Centre \\ Menya & 669 & Spain & West \\ Morrut & 224 & Spain & West \\ Mytrolia & 700 & Greece & Centre \\ Picual & 9 & Spain & West \\ Picudo & 3 & Spain & West \\ Pinonera & 969 & Spain & West \\ Shengh & 1141 & Iran & East \\ Temprano & 358 & Spain & West \\ Uslu & 95 & Turkey & East \\ Verdial de Velez-Malaga-1 & 51 & Spain & West \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._  
Figure 1: Content of the main groups of volatile compounds in the oils of the Core-36. Fruits at the turning stage were hand-picked during years 2008–2012. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Group** & **Sub Subgroup** & **Volatile Compound** & **Codes** & **Min** & **Max** & **Mean** & **Median** & **Caltivies OAV \(>1\)** & **Odor Threshold (ng/g Oil)** & **References** \\ \hline \multirow{4}{*}{C/L/LA} & & (\(\lambda\))-hex-3-small & 6C-1 & 78 & 581 & 236 & 194 & 3 & 450 & [16] \\  & & (\(\lambda\))-hex-3-small & 6C-2 & 82 & 2180 & 399 & 395 & 36 & 17 & [17] \\  & & (\(\lambda\))-hex-2-small & 6C-3 & 175 & 1099 & 587 & 622 & 28 & \({}^{*}\)-244 & [17],[38] \\ \cline{2-11}  & & (\(\lambda\))-hex-2-small & 6C-4 & 4916 & 37,643 & 18,518 & 16,443 & 36 & 424 & [17] \\ \cline{2-11}  & & & (\(\lambda\))-hex-2-small & 6C-5 & 4 & 105 & 29 & 20 & 0 & 1500 & [19] \\  & & (\(\lambda\))-hex-3-small & 6C-4 & 72 & 4306 & 571 & 402 & 3 & 1100 & [17] \\  & & (\(\lambda\))-hex-2-small & 6C-7 & 39 & 559 & 211 & 175 & 0 & 5000 & [20] \\ \hline \multirow{2}{*}{C/L/LA} & & (\(\lambda\))-hex-3-small & hexanal & 6C-8 & 195 & 2175 & 809 & 684 & 36 & 300 & [17] \\  & & & beam-1-cl & 6C-9 & 39 & 1740 & 361 & 183 & 7 & 400 & [19] \\ \hline \multirow{4}{*}{C/L/LA} & & (\(\lambda\))-hex-3-small & 5C-1 & 68 & 1020 & 425 & 358 & 36 & 0,73 & [17] \\  & & (\(\lambda\))-pent-2-small & 5C-2 & 4 & 78 & 24 & 20 & 0 & \({}^{*}\)-300 & [18,34] \\  & & (\(\lambda\))-pent-2-  
The main group of volatile compounds in the oils of the Core-36 cultivars are derived from linolenic acid (LnA), the six straight-chain carbon compounds (C6/LnA), and account, on average, for 4-400 times higher content than those of the rest of volatile compounds in the oils (Table 2). The range of variability for the content of C6/LnA compounds was 6382-40,104 ng/g oil. This range was greater than that found by [PERSON] et al. [29] for oils from 39 different cultivars. However, it was slightly lower than those observed for the segregating progeny of the cross of two of the cultivars from the collection, Picaul and Arbequina (500-51,990 ng/g oil) [30].