Reduced incompatibility in the production of second generation hybrids between two Magnolia species revealed by Bayesian gene dispersal modeling

PREMISE OF THE STUDY: Hybrid zones are areas where gene flow between related species is currently occurring, so information on the compatibility between related species and their hybrids is essential for predicting the dynamics of such zones generated by introgressive hybridization. In this study, we quantified the compatibility among Magnolia stellata, M. salicifolia and their hybrids in a hybrid zone using gene dispersal modeling.
METHODS: After determining the genealogical classes of adult trees in the hybrid zone, a paternity analysis of 574 open pollinated seeds from 37 known maternal trees was performed with microsatellite markers. A neighborhood-based Bayesian gene dispersal model developed by us for estimating compatibility was then applied to the paternity data.
KEY RESULTS: When M. stellata or M. salicifolia were mothers, interspecific mating to produce F1 hybrids yielded significant incompatibility but backcrossing with F1 hybrids did not. Furthermore, when F1 hybrids becam...