Modelling visual quality of Kalanchoe blossfeldiana: influence of cultivar and pot size

An explanatory model for predicting kalanchoe plant height and cropping duration has been developed for one cultivar and one pot size, as described in earlier papers. In two experiments (winter and summer) seven contrasting cultivars ('Anatole', 'Debbie', 'Delia', 'Mie', 'Pandora', 'Tenorio' and 'Toleda') and two pot sizes (7 and 10.5 cm) were analysed to make this model more generally applicable. The studied cultivars showed a strong variation in plant height (10.2 to 29.2 cm) and reaction time (55 to 64 days, from start of short-day period until harvest) when grown under the same conditions (values provided are for summer cultivation in 10.5 cm pots). The effect of pot size on plant height was closely related to the cultivation practices, which already corresponded to model input parameters. For instance, smaller pots resulted in shorter plants but this was due to a lower initial number of internodes and a reduced duration of long-day period. Additionally, growing plants in smaller pots resulted in a longer reaction time especially during winter (on average 8 days delay). The framework of the explanatory model previously developed for 'Anatole' grown in 10.5 cm pots was successfully adapted to other kalanchoe cultivars and pot sizes. It was concluded that when implementing this dynamic model to predict plant height and reaction time for different cultivars in different climate conditions, only few parameters have to be quantified and compared to the reference cultivar at one light and temperature condition.