## 3 Results
### Characteristics of Volatile Compounds  
Fifty-eight types of volatile compounds were detected through GC-MS analysis. Chromatogram profiles between resistant and susceptible varieties of chili showed a difference except for RK-1. The presence of volatile compounds was more varied in susceptible chili varieties than in resistant varieties (Figure 6). Seventeen of the fifty-eight volatile compounds detected by GC-MS had an area greater than 2% (Table 1). Further analysis of the 17 dominant volatile compounds showed that 8 volatile compounds (furan, 2-methyl-; formic acid, 2-methylbutyl ester; furan, 3-butyltetrahydro-2-methyl-, trans-; 1,9-decadiyne; trans-3-decene; 4-octene, 2,6-dimethyl-, [S-(E)]-; cis-2,6-dimethyl-2,6-octadiene; \(\beta\)-cis-ocimene) were correlated with oviposition incidence (Figure 7), and two compounds had a quality value above 90%. Interestingly, \(\beta\)-cis-ocimene was only detected in susceptible variety RK-5 in a significant amount (Table 1).  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \multirow{2}{*}{**No.**} & **RT 1** & \multirow{2}{*}{**Volatile Compounds**} & \multirow{2}{*}{**Q 2 (\%)**} & \multicolumn{6}{c}{**Relative Area (\%)**} \\ \cline{4-9}  & **(min.)** & & & **RK-1** & **RK-2** & **RK-3** & **RK-4** & **RK-5** & **RK-6** \\ \hline
1 & 4.36 & Furan, 2-methyl- & 91 & 0 & 0 & 0 & 10.52 & 12.43 & 0 \\
2 & 4.6 & 1-Hexyne, 5-methyl- & 38 & 11.7 & 0 & 0 & 0 & 0 & 0 \\
3 & 5.87 & Silanediol, dimethyl & 2 & 5.21 & 0 & 0 & 17.26 & 0 & 0 \\
4 & 6.03 & Acetamide, 2-fluoro & 3 & 10.26 & 3.91 & 0 & 0 & 0 & 0 \\
5 & 6.19 & Formic acid, 2-methyl butyl ester & 35 & 0 & 0 & 0 & 0 & 0 & 28.4 \\
6 & 9.52 & Furan, 3-butyltetrahydro-2-methyl-, trans- & 9 & 0 & 0 & 0 & 0 & 0 & 5.36 \\
7 & 11.41 & 1,9-Decadiyne & 27 & 0 & 0 & 3.33 & 0 & 0 & 0 \\
8 & 11.84 & trans-3-Decene & 37 & 0 & 0 & 0 & 0 & 0 & 3.2 \\
9 & 12.19 & 4-Octene, 2,6-dimethyl-, [S-(E)]- & 64 & 0 & 0 & 0 & 0 & 0 & 2.75 \\
10 & 13.14 & cis-2,6-Dimethyl-2,6-octadiene & 80 & 0 & 0 & 0 & 0 & 5.19 & 0 \\
11 & 14.5 & \(\beta\)-cis-Ocimene & 91 & 0 & 0 & 0 & 0 & 17.81 & 0 \\
12 & 21.74 & 1,4-Benzenedi-methanethiol, 2 TBDMS & 36 & 0 & 2.36 & 0 & 0 & 0 \\  & derivatives & & & & & & & \\
13 & 42.25 & 2-Tetradecanol & 35 & 0 & 0 & 0 & 2.78 & 0 & 0 \\
14 & 43.1 & 1-Octadecene & 35 & 7.23 & 0 & 0 & 0 & 0 \\
15 & 43.61 & Butyl dodecyl ether & 35 & 7.51 & 0 & 0 & 4.07 & 0 & 0 \\
16 & 44.26 & Isobutyl nonyl carbonate & 50 & 0 & 0 & 0 & 2.25 & 0 & 0 \\
17 & 46.38 & 1-Decanol, 2-hexyl & 22 & 12.67 & 0 & 0 & 0 & 0 & 0 \\ \hline \end{tabular}
\end{table}
Table 1: Dominant volatile compounds from six chili varieties detected by GC–MS.  
Figure 6: Presence of volatile compounds released resistant and susceptible varieties of chili fruit. Different letters above each column indicate significant differences between the mean values.  
Principal component analysis also mapped the position of resistant varieties and susceptible varieties in each quadrant. The volatile compounds released by RK-5 were similar to those emitted during oviposition incidence, and RK-5 was identified as the variety with the highest oviposition incidence (Figure 8).  
A further test to confirm that insects were attracted to \(\beta\)-cis-ocimene showed that female fruit flies responded to the volatile compounds (ocimene) by increasing the number of ovippositions (Figure 9a) and eggs laid (Figure 9b) compared to the control treatment.  
Figure 8: Relationship of volatile compounds released by six chili varieties (RK1-RK6) with the oviposition incidence (OI) of oriental fruit fly.  
Figure 7: Correlation of seventeen volatile compounds to oviposition incidence (OI) of oriental fruit fly in chili fruit. The number at the horizontal axis represents the volatile compounds described in Table 1.