Vanilla pompona Schiede: Morphological variation of the labellum in localities of Veracruz, Puebla, Jalisco and Oaxaca, Mexico

Abstract

Vanilla pompona is the third most important commercial species of the genus Vanilla, but its morphometric variation is little known. In orchids, infraspecific variation is expressed in the labellum. This study had the objective of analyzing the floral variation of V. pompona collections from localities in Veracruz, Puebla, Jalisco and Oaxaca, Mexico. During the flowering period, we obtained 55 collections of V. pompona flowers, and in the dissected labellum of each flower 54 lines and 7 angles were measured and portrayed with the ImageJ program. With the data obtained, we performed an analysis of variance, a principal components analysis, and a cluster analysis. The results showed significant differences among the collections and localities in the means of the lines of the basal, middle, and apical regions of the labellum. Also, six morphotypes were obtained, and we found that variation was associated with factors such as the environment, geographic barriers, and pollinator pressure. Moreover, we observed variation in flowering dates in one locality of Veracruz. We concluded that there is infraspecific variation within and between the collection localities of V pompona of the Atlantic region (Puebla and Veracruz) and the Pacific region (Jalisco and Oaxaca), Mexico.