TEMPORAL AND SPATIAL VARIATION IN HERITABILITY AND GENETIC CORRELATIONS AMONG FLORAL TRAITS IN RAPHANUS-SATIVUS, WILD RADISH

We measured heritability and genetic correlations of three floral trai ts (corolla width, pollen production per newer and pollen size) in two generations of wild radish (Raphanus sativus) grown in three growth e nvironments (two field sites and the greenhouse). Corolla width and po llen production showed significant heritabilities in both generations and under all growth environments, while pollen size variation appears to be under little genetic control. The estimates of heritability did not vary significantly among generations or among the growth environm ents. Genotype-environment interactions were not apparent for any trai t. Apparently similar selection pressures will result in similar pheno typic changes across generations and across sites. Only corolla width and pollen production were significantly genetically correlated; famil ies with large corollas also had large pollen production. Therefore th e direction and magnitude of evolutionary change of these two traits a re dependent on the relative selection pressures on each.