Temporal and spatial variation in heritability and genetic correlations among floral traits in Raphanus sativus, wild radish

Abstract

We measured heritability and genetic correlations of three floral traits (corolla width, pollen production per flower and pollen size) in two generations of wild radish (Raphanus sativus) grown in three growth environments (two field sites and the greenhouse). Corolla width and pollen 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 environments. Genotype-environment interactions were not apparent for any trait. Apparently, similar selection pressures will result in similar phenotypic changes across generations and across sites. Only corolla width and pollen production were significantly genetically correlated; families with large corollas also had large pollen production. Therefore the direction and magnitude of evolutionary change of these two traits are dependent on the relative selection pressures on each.