Variation in the breeding behavior of the dry forest tree Enterolobium cyclocarpum (Guanacaste) in Costa Rica

We studied the breeding systems of four populations of Enterolobium cycloca rpum (guanacaste, earpod tree) in Costa Rica. Multilocus stimates of the ou tcrossing rate indicate that E. cyclocarpum is a predominant outcrossing sp ecies (t(m) ranged between 0.881 and 0.901) and biparental inbreeding is lo w (range between 0.058 and 0.079). Overall, our analyses showed significant differences in the gene frequencies between pollen and ovules and signific ant differences in pollen gene frequencies between the four populations. We also found significant differences in the pollen gene frequencies calculat ed for single trees in the same population. Outcrossing rates and pollen ge ne frequencies varied in two consecutive years in two populations of E. cyc locarpum. The correlated mating model revealed that there are differences i n the correlation of paternity between populations and years. These finding s indicate that there is variation in the average number of trees that fath er the seed crop of each tree and/or that some fathers are overrepresented in the seed crop of each tree. The implication of these findings for the de velopment of strategies for conservation and management of this species are discussed.