Production of Homozygous Maize Lines Using Maternal Haploid Inducer Lines

The production and use of doubled haploid (DH) lines have gained a significant momentum in maize breeding worldwide due to several advantages they offer over conventional inbred lines. The use of genetically homozygous DH lines simplifies the breeding operations, offers significant time and cost savings, and facilitates greater integration of molecular marker applications to increase selection intensity and genetic gains. The production of DH lines in maize includes several steps, including in vivo production of maternal haploids using appropriate haploid inducers, identification of haploid seeds from the diploid seeds, germination of putative haploid seeds, treatment of the putative haploid seedlings with antimitotic chemicals to double the chromosome number, and seed production from the putative doubled haploids. This chapter outlines the materials and methods used at different steps in maize DH line production.