SD Growth Medium w/o TRP includes a yeast nitrogen base along with ammonium sulfate, and dextrose as the carbon source, which is further supplemented with various amino acids except Tryptophan which makes it a dropout growth medium for yeast cells allowing only tryptophan prototrophic yeast strain to grow. It is used for selection of auxotrophic phenotypes in yeast, selection for plasmid after yeast transformation, for yeast one/two hybrid screening.