Modelling temperature and flower bud growth in November cactus (Schlumbergera truncata, Haw.)

Abstract

A simple dynamic model was constructed describing the relationship between flower bud development and bud length increment in Schlumbergera truncata 'Eva'. A unit development index was calculated from a linear relationship between rate of development and mean day temperature. The flower bud length was calculated using a modified exponential growth equation where time was substituted by the development index. Model parameters were estimated from data from experiments conducted in greenhouse environment at 12, 15, 18, 21, and 24°C. The model gave a good fit to the data with R2-values ranging from 0.999 to 0.967 depending up on the treatment. Model simulations were validated on independent data collected from experiments where plants had been moved between 15 and 21°C. In-the validation it was first towards the end of the cultivation period that the model overestimated the rate of development. The R2-values varied from 0.999 to 0.992 depending on the treatment. When simulations were compared to previously published data from the cultivar 'Madisto' there was a good correlation (R2=0.919). The use of the model in applied production is discussed.