Resumen

RAMIREZ, Nelson et al. Floral morphometric variation in Pachira quinata (Jacq.) W.Alverson (Bombacaceae). Acta Bot. Venez. [online]. 2010, vol.33, n.1, pp.83-102. ISSN 0084-5906.

Variation in floral morphometry of Pachira quinata was evaluated for clones under cultivation conditions at the Irel Station, Barrancas, Barinas State, Venezuela. Six metrical floral traits were considered: floral external diameter, floral internal diameter, diameter of floral tube, floral length, flower tube length, and herkogamy for 91 flowers from 20 Venezuelan clones and 51 flowers from ten Central American clones. Most floral dimensions were positively correlated for South American flowers, and only four pairs of morphometrical floral traits resulted statistically significant for Central American flowers, mainly related with floral length and floral diameter. All floral traits differed according to clone origin. Floral external diameter, diameter of floral tube, floral length, and herkogamy were larger for South American clones, and floral internal diameter and flower tube length were larger for Central American clones. Morphometrical floral traits allow us to discriminate between geographical origins of clones. However, there is a broad range of variation, since only 65% of flowers were properly classified according geographical locality. A second discriminant analysis, using morphological traits, showed significant differences between South and Central American flowers. In order of importance, floral traits that allow discrimination between geographic areas are as follows: 1. hercogamy, 2. external diameter, 3. tube length, and 4. internal diameter. These traits correctly discriminated a high percentage (86.9%) of flowers according to geographic origin. Morphometrical variations of floral traits are discussed in relation to its breeding system, pollination mode and geographical distribution.

Palabras clave : Bombacaceae; floral allometry; floral morphometry; geographic variation; herkogamy; Pachira quinata.