Modeling the Effect of Temperature on the Flower Development Rate of Hybrid Impatiens

Abstract

The effect of average daily temperature (ADT) on flower bud development and subsequent time to flower was investigated on hybrid impatiens (Impatiens ×hybrida) cultivars Compact Electric Orange, Compact Hot Coral, and Compact Orchid Blush. Plants with a visible flower bud measuring 2 mm in width were placed in one of the four greenhouses with temperature setpoints ranging from 16 to 28 °C. Flower bud width was measured every 3 days in each ADT treatment until flowering. The subsequent days to flower (DTF) from the onset of a visible bud decreased from 36 to 27 days as the ADT increased from 17 to 28 °C. The DTF from visible bud varied by <3 days among the three cultivars across all temperatures; therefore, cultivar data were pooled to create a stronger prediction model. A logistic formula was used to predict the remaining DTF as a function of flower bud width and ADT. The model accurately described the effect of bud width and ADT on flowering time within ±3 days for 87% of the actual DTF across all three cultivars. The resulting flower development model provides greenhouse growers with a guide for manipulating temperature to produce flowering plants for specific market dates based on flower bud width measurements.