The proposed research is aimed at eventually developing a "Mendelian" and molecular framework for quantitative genetics using height in maize as a model system. By correlating dwarf loci exhibiting extreme effects upon plant height (particularly those involved in gibberellin biosynthesis) with loci demonstrated by RFLP analysis to affect variation in height quantitatively, it should be possible to verify the hypothesis that major "Quantitative Trait Loci" and "single-gene mutant loci" in many cases will simply represent alternative alleles at the same locus. This effort will follow up on earlier RFLP analysis which demonstrated a casual positional correlation between the two types of loci. By measuring the effect of exogenously-added gibberellin (GA) upon the actions of plant quantitative loci and determining the positions of maize dwarf loci with respect to RFLP marker loci, a stronger linkage could be obtained that will demonstrate that plant loci controlling GA levels can affect phenotypic variation, both quantitatively and qualitatively. The results of this work will directly facilitate cloning efforts for these genes that could then be used to study how variation in individual gene action contributes to variation in complex phenotypes and how that variation is modulated by environmental influences.*** //
