FIGURE 13.11 Diversity structure of 42 cultivated vanilla and Vanilla bahiana accessions and detailed relationships of the Polynesian accessions derived from neighbor joining trees using the distance matrix of Sokal and Michener (529 variables and 1000 bootstraps).
Some others cultivars were not discriminated by their AFLP pattern; this was the case of Tahiti and Haapape. Their morphological differences were unambiguous; nevertheless, their genetic diversity has been found to be only the consequence of the number of copies of each AFLP marker. For this reason, cytogenetic analyses were developed.
As previously described for V. planifolia by Nair and Ravindran (1994), all the cells of a single root do not present the same chromosome value for Tahitian vanilla. We also observed these variations for the accessions of V. planifolia and V. pompona. Three ploidy levels were observed among the Polynesian accessions. The chromosome counts for numerous metaphase plates of root tips, and the genome size measurements by flow cytometry were concordant. Three groups were distinguished:
1. A diploid group (2×) with chromosome number ranging from 22 to 31 and with a genome size from 4.87 to 5.80 pg. These characteristics concerned the majority of the Polynesian cultivars: Tahiti (Figure 13.12), Rea rea, Parahurahu, Oviri, Paraauti, Potiti, Puroini, Pupa, Popoti, and Poura.
2. A triploid group (3×) for which the chromosome number varies from 33 to 41. This group contains two sterile vanilla plants called “Haapape sterile” showing abnormal flower physiology (absence of pollen and autoincompatibility).
3. A tetraploid group (4×) where the number of chromosomes and the genome size are twice as high as in the first group (43–56 chromosomes and genome size of 10.10–10.89 pg). The following are the cultivars: Haapape, Ofe ofe, Tiarei, and Tahiti long.
FIGURE 13.12 Metaphase plates of (a) cultivar Tahiti with 24 chromosomes and (b) cultivar Haapape with 52 chromosomes.
Conclusion
The originality of Tahitian vanilla is due to its morphology, its texture, and the aromatic content of its pods. These characteristics are indeed related to genotype. They are also influenced by geographical areas of cultivation. For example, beans of Tahitian vanilla produced and cured in French Polynesia are different from those produced in other countries. The rare and highly considered gourmet French Polynesian spice results from a combination of the factors the soil, the climate, and also the Polynesian people, who carefully produce and cure the vanilla beans.
Acknowledgments
The authors thank Dr. S. Siljak-Yakovlev (Univ. Paris Sud) and Dr. S.C. Brown (CNRS Gif sur Yvette) for their help in cytogenetic analysis and for their interest and support to Tahitian vanilla genome studies, and J. Foster for his invaluable comments on the manuscript.
References
Adedeji, J., T. G. Hartman, and H. Chi-Tang. 1993. Flavor characterization of different varieties of vanilla beans. Perfumer & Flavorist 18 (2):25–33.
Andrzejewski, S., S. Causse, C. Charon, M. Dron, M. F. Duval, S. Siljak-Yakovlev, and M. Wong. 2006. Diversité génétique des vanilliers cultivés en Polynésie française. Poster presented at the IVème Colloque International sur les Plantes Aromatiques et Médicinales des Régions d’Outre-Mer, Papeete, Tahiti.
Black, J. M. 2005. Vanilla bean volatile analysis origin & species. Vanilla 3rd International Congress. Veracruz, Mexico.
Bouriquet, G. 1954. Le vanillier et la vanille dans le monde. L’encyclopédie biologique no 46. Paul Lechevalier, Paris, 748 pp.
Bouriquet, G. and E. Hibon. 1950. Quelques vanilliers cultivés dans les établissements français d’Océanie. L’agronomie tropicale 1–2:54–61.
Brunschwig, C., F. X. Collard, M. Wong, J. P. Bianchini, and P. Raharivelomanana. 2007. The fatty acid composition of Vanilla tahitensis. Poster presented at the Vanilla 3rd International Congress, Jamesburg, New Jersey.
Chevalier, A. 1946. La systématique du genre Vanilla et l’amélioration des plants de vanille. Revue de botanique appliquée et d’agriculture tropicale 281–282:107–111.
Collard, F. X. 2007. Evolution of aroma compounds in V. tahitensis during the curing process. Poster presented at the Vanilla 3rd International Congress, Jamesburg, New Jersey. Collard, F. X., C. Brunschwig, and M. Wong. 2006. Détermination de la composition aroma-tique de quelques variétés de Vanilla tahitensis par Chromatographie Liquide Haute Performance. Oral presentation at the IVth CIPAM, Papeete, Tahiti.
Costantin, J. and D. Bois. 1915. Sur trois types de vanilles commerciales de Tahiti. Compte-rendus de l’académie des Sciences de Paris 161:196–202.
Da Costa, N. C. and M. Pantini. 2006. The analysis of volatiles in Tahitian vanilla (Vanilla tahitensis) including novel compounds. Flavour Science: Recent Advances and Trends 43:161–164.
Duval, M. F., S. Bory, S. Andrzejewski, M. Grisoni, P. Besse, S. Causse, C. Charon, M. Dron, E. Odoux, and M. Wong. 2006. Diversité génétique des vanilliers dans leurs zones de dispersion secondaire. Les actes du BRG 6:181–196.
Ehlers, D., M. Pfister, and S. Bartholomae. 1994. Analysis of Tahiti vanilla by high-performance liquid chromatography. Zeitschrift für Lebensmittel Untersuchung und Forschung 199:38–42.
Fayet, B., C. Tisse, M. Guerere, and J. Estienne. 1987. Nouveaux critères analytiques dans l’étude des gousses de vanille. Analusis 15 (5):217–226.
Florence, J. and M. Guérin. 1996. A propos de la vanille à Tahiti. L’orchidée 13:84–87. Gassenmeier, K., B. Riesen, and B. Magyar. 2008. Commercial quality and analytical parameters of cured vanilla beans (Vanilla planifolia) from different origins from the 2006–2007 crop. Flavour and Fragrance Journal 23:194–201.
Hartman, T. G. 2003. Composition of vanilla beans from different geographical regions. First International Congress on the Future of the Vanilla Business. Princeton, New Jersey. Henry, C. 1924. Caractères généraux des différents vanilliers cultivés à Tahiti. L’agronomie tropicale 79:133–136.
Joulain, D., R. Laurent, J. Maason, J. C. Beolor, and H. Brevard. 2007. Heliotropin, heliotrope odor and Tahitian vanilla flavor: The end of a saga? Natural Product Communications 2 (3):305–308.
Klimes, I. and D. Lamparsky. 1976. Vanilla volatiles: A comprehensive analysis. International Flavours and Food Additives 7 (6):272–273, 291.
Langella, C., F. Saltron, and M. Guerere. 2003. Dosage et analyses isotopiques des composés phénoliques de la vanille: mesure de fidélité. Ann. Fals. Exp. Chim. 96 (962):73–86.