S19 - Session O6 - Effect of nitrogen fertilization on flowering of strawberry (Fragaria × ananassa v. Sonata)

Authors: Anne Hykkerud *, Inger Martinussen, Anita Snsteby, Tomasz Woznicki

Background: Cultivation of strawberries under high tunnels in substrate is increasing worldwide including in Norway. This production system requires high inputs and as a consequence high yield is needed for profitability. Production of plants with high flowering and yield potential is therefore of is therefore a prerequisite. June-bearing strawberry initiates flowers under short-day (SD) conditions. Flowering of strawberry may also be modified by nutrient status, especially nitrogen (N). However, previous studies have showed that the nutritional effects on flowering in strawberry are complex. An important aspect of the fertilization in June-bearing strawberries is available N before and after flower initiation (SD period). Material and method: In order to provide more knowledge on this issue, an experiment have been carried out under controlled environment conditions with the strawberry cultivar Sonata in which various levels of nitrogen (high-medium-low) was supplied pre and post flower-inducing SD treatment. During this period growth and development was monitored. Results: The result indicates that when applying low N levels pre-SD the plants flowered later compared to the higher N levels. Low N level both pre and post SD treatment produced fewest flowers, while a low pre-N level fallowed by high post-SD produced same amount of flowers as high N level pre and post SD. The main effect of the variation in the number of flowers was due to the interaction between N availability pre and post SD. In addition number of flower stems, leaves and dry weigth was affected.