Isozyme analysis of rain forest plants using immature seeds

[Abstract] Genetican analysis of tropical plant species has the potential to address a range of evolutionary and ecological questions. For example, recent studies have measured genetic variation within and between species (review in Bawa 1994, Hamrick 1994), phylogenetic relationships among species (Sytsma & Schaal 1985, Prober et a1 1990), and genetic variation in widespread and narrowly endemic species as evidence for Pleistocene refugia (Lewis & Crawford 1995). Isozyme studies on tropical plants have estimated the outcrossing rate for a range of species (review in Bawa 1992, 1994), and have considered the potential effect of breeding system and ecological factors such as tree density (Murawski & Hamrick 199 1) and pollen and seed dispersal patterns (Bawa 1994, Hamrick 1994, Loiselle et al. 1995) on genetic Variability within ecologically similar species. The effect of forest fragmentation on outcrossing rate and genetic variability also has been recently addressed, both theoretically (Bawa 1994, Hamrick 1994, Nason et al. 1997) and by analysis of variation in a single species at a range of field sites (Hall et al. 1996). Genetic analyses are also useful for comparing provenance and family variation within tropical timber tree species (Wickneswari & Norwati 1993, Chase et al. 1995) and to conserve variation and select for desirable growth performance and environmental adaptability