An experiment to partition the components of variation in selected lines of triticale was conducted at Lincoln, Canterbury, New Zealand. Genetic variation, genotype × environment interaction, and phenotypic stability of 20 quantitative characters, as well as biochemical variation were studied in 11 hexaploid triticale lines. For the quantitative study, the lines were grown in four environments. The randomised complete block design was used in each environment. Data were collected on an individual plant basis except for five characters, measured on a plot basis. The results showed that genetic variation for most of the characters was high as expressed by the high broad sense heritability (>50%). Biochemical variation showed major differences between lines, though each line, except ‘Till’ and ‘Salvo’, was relatively homogenous. Genotype × environment interaction was strong for 16 characters. Lines such as ‘Lasko’, ‘Salvo’, ‘Presto’, ‘Juanillo’, ‘Aranui’, and ‘Swans’ have great potential for triticale yield improvements as they had average stability and were well adapted to all environments. Of the early maturing lines—'Fulis’, ‘Juanillo’, ‘Swans’, and ‘Till’ are likely to be the best for incorporation in the breeding programme as they had average stability and could be harvested earlier than other lines.