kukintaajankohta

Kukintaajankohta, or flowering time, is the period during which a plant produces flowers (anthesis) and may include the onset, peak, and duration of flowering. It is a trait shaped by genetic factors and environmental conditions, and it varies among species, cultivars, and populations. Flowering time influences reproductive success, pollination opportunities, seed set, and, for crops, yield and quality. In many plants, flowering is controlled by photoperiod (day length), temperature (vernalization or vernalization requirement), and moisture and nutrient status. Plants may also exhibit plasticity, altering timing in response to ambient conditions, and exhibit genotype-by-environment interactions.

In practice, flowering time is measured as the date of first open flower, the date of peak flowering, or the window of flowering, often reported as day of year. Standard scales such as the BBCH growth stages are used in research to describe phenology. Flowering time data support plant breeding, enabling selection for early or late flowering, synchronization with pollinators, or avoidance of frost. They are also used in ecological studies to understand plant–pollinator networks and in agriculture for planning sowing, pruning, irrigation, and harvest schedules.

Climate change is affecting kukintaajankohta, with trends toward earlier and sometimes more variable flowering in many regions, leading to phenological mismatches and agricultural risk. Adaptive breeding and management aim to stabilize flowering timing under changing conditions.