Cinnamomum zeylanicum Blume is a commercially important species cultivated in Sri Lanka and traded as Ceylon cinnamon or true cinnamon. In addition, seven endemic wild species of the genus Cinnamomum have been reported in Sri Lanka. The literature on wild relatives of C. dubium, C. capparucoronde, C. citriodorum, C. litseaefolium, C. ovalifolium, C. rivulorum and C. sinharajaense is limited. Therefore, proper field level identification and differentiation of both wild and cultivated species are critical for the conservation and utilization of such species. Since the cinnamon is a crosspollinated species, intra-species diversity is also a possibility. Our work focused on inter-and intra-species diversity of Cinnamomum leaf morphology to develop a "Leaf Morphological Index" for field-level identification of reported species. Forty accessions, representing a minimum of two from each species, collected from natural and cultivated habitats, were assessed with 12 morphological characters. The highest within-species variation was observed in C. zeylanicum, followed by C. dubium. Of the morphological characters, five-leaf traits, leaf shape, apex, base, venation, and size significantly contributed to the main principle components. Therefore, those traits were used for developing a leaf morphological index. The morphological index could distinguish all the species at the field level.
The genus Cinnamomum has 250 species distributed from South, East and South East Asia to Australia. There are eight species of cinnamon grown in Sri Lanka, of which, Cinnamomum verum Pres1 (syn. C. zeylanicum Blume) which is widely cultivated in the country. In addition, seven other species of wild cinnamon are also grown which are endemic to Sri Lanka which are considered wild cinnamon. In this study, six Cinnamomum species were selected namely Cinnamomum verum, Cinnamomum dubium Nees (Sinhala: Sewel Kurundu or Wal Kurundu), Cinnamomum citriodorum (Sinhala: Pangiri Kurundu), Cinnamomum rivulorum Kostermans, Cinnamomum sinharajense Kostermans, Cinnamomum capparu-corende (Sinhala: Kapuru Kurundu). Much work has been carried out with Cinnamomum verum, however, work on wild cinnamon varieties is scanty. In this backdrop, this study was carried out to identify and quantify the major chemical constituents of volatile oils obtained from bark and leaves of wild and true cinnamon species cultivated or grown in Sri Lanka. It was revealed that leaf oil of Cinnamomum verum contains significantly (p<0.05) higher percentage of volatile oil (3.23%). The highest bark oil content (3.53%) was observed in Cinnamomum sinharajense, the lowest leaf oil (0.41%) and stem bark oil (0.51%) contents were observed in the Cinnamomum rivulorum. Fifteen major volatile chemical constituents were identified by Liquid Gas Chromatographic analysis in the essential oils obtained from bark and leaf of different cinnamon species. The highest cinnamaldehyde content (67.57%) was observed in Cinnamomum verum. Cinnamomum sinharajense contained comparatively higher amount of cinnamaldehyde (57.46%) than the other wild cinnamon species. The highest euginol content (87.53%) was observed in Cinnamomum sinharajense leaf. When compared with the chemical composition of Cinnamomum dubium leaf oil, geraniol was the most abundant (24.05%) among the volatile chemical constituents. β-Caryophyllene (41.31%) was identified in Cinnamomum dubium stem bark oil. The highest Euginol (22.29%) content was present in essential oil obtained from Cinnamomum rivulorum stem bark which was not observed in other cinnamon species.
The national average productivity of cinnamon (Cinnamomum zeylanicum Blume) in Sri Lanka (445 kg/ha) is far below than the attainable yield (1000 kg/ha), which may have an association with pest and disease incidences. Pest and disease incidence was hypothesized to be correlated with awareness of farmers, agronomic practices that implemented in the field, weather parameters, and scale of farming. Hence, better understanding on these relationships is essential for planning a crop management package to increase the cinnamon yield. This study was thus, carried out to investigate the occurrence of pest and disease complex in cinnamon ecosystem, and its’ association with yield level and agronomic practices carried out in cinnamon fields. A detailed field survey was carried out in Galle, Matara, Ratnapura, Kalutara and Hambantota districts of Sri Lanka visiting 260 cinnamon lands during February to May 2013. Information was collected by interviewing the farmers, and making field observations. Significant negative correlations (r = -0.668; p<0.05) were observed between the yield of cinnamon and incidence of wood borer (Ichneumoniptera cinnamomumi;) and rough bark disease (Phomopsis spp.; r = -0.655). Vertebrate pests such as barking deer and peacocks were making a significant damage on the new shoots that appear after harvesting. In addition, ten occasional pest and disease incidences and several minor pest and diseases were observed during the study period. There was a positive correlation between the severity of pest and disease incidence and the overuse of fertilizer and mammoty weeding. A negative correlation was observed between the pest and disease incidence and selective pruning, harvesting in short intervals (4 – 6 months), and slash weeding. Agronomic practices that had negative correlation with pest and disease incidence should be promoted through farmer awareness programmes. The results suggest upgrading the cinnamon crop management package to include these practices.
The maturity dependence of quality and quantity of bark and leaf oils of Ceylon Cinnamon were studied. Both genetic factors and ecological factors were maintained constant using two accessions of Ceylon Cinnamon, Sri Gamunu and Sri Vijaya, vegetatively cultivated at a field in the same agroecological zone, IL1a (6 0 1.7820N'; 80 0 33.4990'E; 22.3 amsl.). Three maturity stages of plants, more than 5 years, between 2-2.5 years, and between 1.5-2 years, were used. Morphological analysis in two varieties showed that stick weight, bark dry weight, and leaf dry weight per stick were not significantly different in two varieties at the significance level α = 0.05. When compared the oil contents, Sri Gamunu had a higher oil yield than Sri Vijaya and both showed significantly higher yield at maturity stage of 2-2.5 years which was about the customarily identified maturity for harvesting (~2 years). In Sri Gamunu, about 78 % of bark oil consists of cinnamaldehyde and cinnamyl acetate while those in Sri Vijaya accounts only about 63% with higher content of eugenol and benzyl benzoate. In contrast, eugenol was the major component in leaf oil of cinnamon, which accounts for about 80 % and 87% in Sri Gamunu and Sri Vijaya, respectively. The study revealed that the best maturity stage to harvest both varieties of cinnamon is 2-2.5 years of maturity for maximum quality and quantity of cinnamon bark oil.
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