2.5 | Chromosome preparation and in situhybridization
Chromosomes were prepared for GISH analysis according to the method of Han et al. (2004). Total genomic DNA was extracted from fresh leaves by the CTAB method (Murray & Thompson, 1980). Plasmids (from positive clones that are St genome) and the StY genome were labeled with fluorescein-12-dUTP or Texas-red-5-dCTP using the nick translation method. Hybridization procedure, detection, and visualization were performed according to the method of Wang et al (2017).