dagneutrale

Dagneutrale refers to plants whose flowering is not governed by photoperiod, meaning they initiate blooming regardless of the length of day or night. The term is used in Danish and Norwegian horticultural contexts to describe species and cultivars that do not rely on long or short days to trigger flowering, in contrast to short-day and long-day plants.

Etymology and usage: The word dagneutrale combines elements meaning day and neutral. In English-language horticulture, the term day-neutral is commonly used, and dagneutrale is the equivalent in Scandinavian languages. The concept helps growers categorize crops by their flowering response to light.

Mechanisms: In day-neutral plants, flowering is less dependent on day length and more influenced by other factors such as plant age, temperature, hormonal signals, or internal developmental cues. While photoreceptors and flowering pathway genes play roles in many species, dagneutrale cultivars exhibit flowering responses that can occur under a wide range of photoperiods. Temperature and vernalization can still affect flowering in some cases.

Examples and applications: Tomato and cucumber are widely cited as day-neutral crops, producing flowers and fruit across various day lengths. Some strawberry cultivars are also considered day-neutral, enabling production outside strict seasonal windows. Several ornamental species, including certain roses, may show day-neutral tendencies. For greenhouse producers, dagneutrale crops offer more predictable or flexible flowering schedules, which can improve year-round production when combined with controlled environmental conditions.

Limitations: Day-neutral behavior can vary among varieties and may be influenced by temperature, nutrition, or extreme environmental conditions. Understanding a crop’s specific flowering behavior remains important for effective cultivation.