FIGURE 1.

Plant material used in this study. Wheat (T. aestivum cv. Chinese Spring) was crossed as the female parent with rye (S. cereale cv. Petkus). The resulting interspecific wheat–rye hybrids are completely sterile. To obtain the octoploid triticale (×Triticosecale Wittmack), wheat–rye hybrids were treated with colchicine to double the chromosome number. The same crossing scheme was used to obtain the wheat–rye hybrids and the octoploid triticale, both lacking the Ph1 locus; only this time, wheat lacking Ph1 was used as the female parent for the initial crosses.