GM barley (Hordeum sp.). Genetic modification (GM) of plants involves altering their Deoxyribonucleic acid (DNA), the molecule that controls every part of an organism's growth and development. This is a double haploid" trial where pollen cells (micro- spores) are cultured so that they form embryos with only half of the DNA's chromosome pairs (haploid). These haploid cells are then treated so that they duplicate the chromosomes present, forming a double haploid cell. The plants that are developed from these cells have beneficial traits such as increased yields. This technique can also be achieved through selective breeding, although a true double haploid is never achieved."