9307747 Mitchell Olds Molecular Biological approaches to quantitative genetics can be used to study in breeding depression and hybrid breakdown. The genetic basis of inbreeding dpression is an unanswered question with implications for many problems in agriculture and genetics. For example, hybrid vigor (avoidance of inbreeding depression) is responsible for a large portion of the increases in crop yield obtained by plant breeders. Crosses between distantly related populations may produce offspring with reduces fitness (hybrid breakdown). Phenotypic plasticity and genotype environment interaction may also be important in agricultural and wild species. Despite many years of inquiry, the genetic basis of these phenomena remains unclear. %%% Using recently developed techniquesin molecular biology it is now feasible to elucidate the genetic basis of ombreeding depression and outbreeding depression. This technology will be used to ask 1) What causes hybrid vigor? 2) Does genotype environment interaction contribute to hybrid vigor? 3) How do changes in gene expression cause genotype environment interaction? 4) What causes hybrid breakdown? This research will have important implications for understanding the genetics of agricultural and natural populations.
