Genetic variation for the time of first flower and shoot length in Hybrid Tea-rose seedling populations under a range of temperatures

Seedlings of 30 Hybrid Tea-rose populations were grown at 6 constant temperatures (10, 14, 17, 20, 23 and 26°C) under natural light conditions in greenhouses of the IVT-phytotron. Significant differences only occurred between populations in the number of days to first flower or shoot length at first flower. The two characteristics were not affected by genotype-temperature interactions. Several populations occurred that combined a short number of days to first flower with a long shoot. Selection for adaptation to low growing-temperatures is discussed.