Three vanilla species are cultivated in the world: V. planifolia, V. pompona and V. tahitensis. Tahitian vanilla is characterized by anise notes [1] and oily texture. Its diversification
seems to have occurred in French Polynesia since its introduction and despite its
vegetative mode of propagation [2]. Vanilla growers distinguish about twenty cultivars
according to their morphological traits but in local farms, two cultivars are mainly
produced: „Tahiti“ and „Hapape“. More than two hundred plants have been collected
in the Polynesian islands and grown in a preservation shade house.
Tahitian vanilla biodiversity is investigated using morphological, genetic, aromatic
and lipidic traits. To assess genetic diversity, fingerprints (AFLP) and chromosome
counts were realized. The chemical composition of the pods was investigated by HPLC
analysis of aromatic compounds and fatty acids. Many morphological traits were also
measured.
We report here the results of the diversity characterization of five cultivars which
were chosen for their large variation in morphological traits. The five cultivars
show differences in their fingerprints and/or in their diploidy level. Moreover, they
are well discriminated by their aroma and fatty acid compositions. The two most distinct
cultivars, according to their genetic pattern, also present the most divergent chemical
compositions.
Such a combined analysis may provide useful information for breeding programs by allowing
i) the selection of the best cultivars according to their aromatic and fatty acid
composition, ii) the identification of genes related to the flavor and fatty acid
biosynthesis for the selection of the best hybrids.
References: [1] Da Costa, C. et al (2006) Dev. Food Sci. 43:161–164.
[2] Duval, M.F. et al. (2006) Les Actes du BRG 6:181–196.
