**4. Chromosome doubling of identified haploids**

The next objective is to create DH lines from the haploids after a successful induction cross using an appropriate inducer [3]. Haploids are normally infertile since they only have one copy of each chromosome, thus they must be chromosomally duplicated. Chemicals that prevent haploid seedlings from mitotically duplicating are used to achieve artificial chromosomal duplication (**Figure 4**). Colchicine is the chemical of choice in DH pipelines for artificial chromosomal doubling [1, 3]. Initially, haploid seeds are recognized using any of the markers and then germinated on paper towels until the coleoptiles reach a length of 2 cm. Before submersion in colchicine, the coleoptile tip is cut off, and the seedlings are rinsed out under tap water. The seedlings were then placed in trays filled with peat moss and kept at room temperature until they reached the three-leaf stage. Viable seedlings were then transplanted to a DH nursery field with suitable row-to-row and plant-to-plant spacing [3].
