Haploid plants have one set of chromosomes in their
genome and are usually sterile. However, upon spontaneous chromosome doubling or treatment with
chromosome doubling reagents, they can produce doubled haploids (DHs), which are valuable homozygous materials in plant breeding. In contrast to conventional breeding, which takes 6–8 generations to develop an inbred line of about 99 % homozygosity , the DH technology has reduced the time and resources significantly to reach 100 % homozygosity and thus has become a major aid in maize breeding