The present disclosure provides compositions and methods for the editing or mutating of specific subtypes of GA20 oxidase genes and specific zygosity combinations of those edits or mutations. Modified plants, and plant parts and cells thereof, having mutations reducing the expression or activity of GA20 oxidase genes are further provided with improved characteristics, such as reduced plant height and increased lodging resistance, but without off-types. Methods are further provided for making modified plants, and plant parts and cells thereof, having one or more mutations in specific subtypes of GA20 oxidase genes.