Removal of stamens from a bisexual flower before amhesis is called emasculation. Emasculation is done during hybridization for preventing self pollination. Mass selection : It involves selection of seeds of phcnotypically superior plants and sowing them in next generation. Pure line selection : In this method a plant with desirable traits is first selected from the genetically mixed population and then salted. After several such generation a few plants are finally selected which prove to be homozygous for the characters. Clonal selection is the type of selection applicable to vegetatively propagated plants eg. Banana.