ISHS Acta Horticulturae 51: Symposium on Protected Cultivation of Flowers and Vegetables
THE INFLUENCE OF THE TIME OF PROPAGATION, PINCHING AND SHORTDAY TREATMENT ON THE GROWTH AND DEVELOPMENT OF EUPHORBIA PULCHERRIMA |
| Author: | O. Voigt Christensen |
| Abstract:
It is possible to remove the apical dominance in Euphorbia pulcherrima Willd by manual pinching or by short day treatment. Manual pinching can be done at the same time as propagation, but if the short day treatment can be undertaken at the same time it will be a more rational method. Before short day pinching can be successful, it is necessary to know, how many short days are needed to induce all plants with the first order cyathium and how many plants then are induced with the second order cyathium. Furthermore, the question is how many leaves will an induced plant develop? Four experiments have been carried out, and they show that it takes from 4 to 20 days to induce Euphorbia pulcherrima cuttings to the first order cyathium. In most cases 15 short days are needed so all the plants are induced, but by then 40 to 90 per cent of the plants have initiated the second order cyathium. If the cuttings have 4–5 fully developed leaves at the time of propagation the total number of leaves up to the first order cyathium is as a mean 16. Short day pinching of Euphorbia pulcherrima is not suitable because of the above mentioned reasons and also due to the variation among the plants although treated alike. | |
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