Resumen

RAMIREZ, Nelson et al. Reproductive efficiency of Pachira quinata (Jacq.) W. Alverson (Bombacaceae) clones under cultivation conditions. Acta Bot. Venez. [online]. 2008, vol.31, n.2, pp.367-386. ISSN 0084-5906.

The reproductive efficiency of clones of Pachira quinata was evaluated under cultivation conditions in the garden and seed clonal orchards at El IREL, Barrancas, State Barinas, Venezuela. Four variables of reproductive efficiency were considered: abortion of seeds, production of seeds by ovule, production of fruits by flower and the relative fecundity, which is expressed as the number of good seeds produced by ovule by inflorescence. Each one of these variables was determined for each clone and then compared according to the origin of the clones (four of Venezuelan origin and four of Central American origin). The percentage of seeds aborted by fruit shows that the impact on the total production of seed set is highly variable (1.3-29.2%), although most of the percentage values of seeds aborted by fruit were inferior to 20%,with an average value of 10.9%. The production of seeds by ovule was from 20.3 to 49.5% with an average of 33.7% seeds per ovule. The relation fruit/flower was low and varied between 7.1 and 50.0%, nevertheless, most values of fruit production were around 20%. The relative fecundity varied from 3.7 to 14.5%, averaging 6.61%. The production of fruits per flower and the relative fecundity were the only reproductive variables statistically different among clone origins. According to the results of correlation matrix,60.8% of the variance in the fecundity is explained by the production of fruits per flower. According to the information of previous studies, the results obtained in the reproductive efficiency may be associated to the genetic self incompatibility, pollinator limitation, resource limitation and the neighborhood of ramets of the same clones in the plantation.

Palabras clave : Clonal; fecundity; fruit set; Pachira quinata; seed abortion; seed orchards; seed set; Venezuela.