LOW-TEMPERATURE TOLERANCE OF OCTOPLOID TRITICALE AND ITS PARENTAL SPECIES GROWN IN SOUTHERN ONTARIO

The low-temperature tolerance of 25 octoploid triticale (× Triticosecale Wittmack) lines and their five wheat (Triticum aestivum L. em. Thell) and five rye (Secale cereale L.) parental cultivars was evaluated in controlled freezing tests following field acclimation in southern Ontario. The average LT50 rating of triticale was 1–2 °C inferior to that of wheat and rye. Triticale synthesized from very hardy rye did not have better levels of hardiness than triticale from less hardy rye. The raw primary octoploid triticale lines were generally less cold tolerant than their hardy wheat parents. The LT50 rating of triticale was not significantly correlated with the LT50 rating of either the wheat or the rye parent.Key words: Triticum aestivum L. em. Thell., Secale cereale L., cold hardiness, intergeneric hybridization