Genetic Linkage Map and Diversity Analysis of Tahitian Vanilla (Vanilla xtahitensis, Orchidaceae)

The first vanilla genetic linkage map was constructed by analyzing the progeny of an interspecific cross between Vanilla xtahifensis J. W. Moore (pro sp.) and Vanilla pompona Schiede. The two-way pseudotestcross mapping strategy was used and a total of 225 amplified fragment length polymorphism (AFLP) markers were mapped on 18 linkage groups covering 1035.85 cM. Thirteen tahitian vanilla morphotypes, one Vanilla planifolia Andrews and recent hybrids were compared by measuring seven morphological traits and by genotyping, with 539 AFLP fragments. The morphotypes studied showed relatively homogenous stem traits but differed in their bean and leaf traits as in their AFLP pattern. Genetic variability and AFLP genotyping comparison suggest a diversification in French Polynesia based on sexual reproduction and are consistent with the hypothesis of a single introduction event. These results are the first step for vanilla breeding program and will be also useful for tahitian vanilla resource preservation.