This invention pertains to a method for manipulating the growth rate and/or yield and/or architecture of a genetically modified plant, as compared to a corresponding wild-type plant. The method relies on over-expression of an endogenous or exogenous gene encoding a cis-prenyltransferase enzyme. In a preferred embodiment, transgenic plants obtained by this method exhibit increased growth rates to maturity, increased seed production, and increased height, siliques, and leave area.