Performance of 40 poinsettia cultivars grown under two different temperatures

摘要

This study evaluated forty poinsettia cultivars to determine which cultivars perform well under cool?growing temperatures. Poinsettias were grown in separate greenhouses at temperatures of 20°C during?the day and 17°C at night for cold production, or 25°C during the day and 22°C at night for warm?production. Number of lateral shoots leading to inflorescences, number of bracts, canopy diameter, and?stem diameter was determined. A significant (P= 0.03) cultivars by greenhouse temperature interaction?existed for all parameters measured. Cultivars were then separated into classes based on greatest?values for each trait. Poinsettia cultivars with the largest stem diameter in both warm and cold?production systems included ‘39-02B’, ‘7-07’, ‘Classic? White’, and ‘Enduring? Red’. Poinsettia?cultivars ‘HC-18B’, ‘Winter Blush’, ‘Cortez? Burgundy, ‘Winter Rose? Early Red’, ‘7-07’, ‘Silverstar??Red’, ‘Topez’?, ‘Classic? Red’, ‘Enduring? White’, Novia? Red’, Advent? Red’, ‘Silverstar? Marble’,?and ‘1232’ had high bract numbers in both warm and cold production. Only one cultivar, '1266',?produced a large number of lateral inflorescences in both production systems. Poinsettia cultivars?‘Classic? White’, ‘Mira? White’, ‘Novia? Red’, Early ‘Orion? Red’, ‘Mars’? Pink’, and ‘Enduring??Red’ had larger canopy diameters when grown in cool temperatures than under warmer conditions.