Diversity and morpho-chemo correlations of Cinnamon (Cinnamomum verum J. Presl) bark oil from Sri Lanka

The wide natural variation of Cinnamomum verum morphology in Sri Lanka suggests the chemo-diversity, which must be revealed for efficient utilization in a vast scope of industries. This study was carried out to determine the variation of essential oil constituents of cinnamon bark from major growing areas of Sri Lanka, morphological markers for oil constituents and genetic relationships for the correlations among major chemical constituents. E-Cinnamaldehyde (CM), (E)-Cinnamyl acetate (CA), Eugenol (EU), Benzyl benzoate (BB), linalool (LN) and β-caryophyllene (CR) were the highest abundant six out of 188 constituents reported through GC-MS analysis of bark essential oil. The mean values and 95 % confidence intervals of CM, CA, EU, BB, LN and CR were 65.10 ± 2.4 (60.15, 70.05), 15.93 ± 2.14 (11.51, 20.34), 4.07 ± 0.42 (3.19, 4.95), 3.21 ± 0.52 (2.15, 4.28), 1.44 ± 0.16 (1.09,1.79) and 1.31 ± 0.10 (1.11,1.53) respectively. CM was the highest abundant in 29/30 accessions, while CA was the highest abundant only in 1/30. CM varied with growing district. CM was negatively correlated with CA, (r = 0.81) at the 0.01 % level of significance irrespective of the growing district. The correlation between EU and BB was significant (r = 0.49) at 0.01 % level of significance. Chemical constituents were linked with the morphological characters: The leaf width (LW) was correlated with EU, (r = 0.37) at 0.05 % level of significance and the bark thickness (BT) was in a correlation with CR, (r = 0.54) at 0.01 % level of significance. Gene network model analysis identifying two pathways for CM, CA and BB biosynthesis, and two pathways for EU biosynthesis explained the correlations between major constituents.