Factors Influencing Flower Initiation in Caraway (Carum carvi L.)

ABSTRACT The ecological and biological factors which may influence flowering of caraway were investigated. Temperature and the length of the induction had a role in flower initiation. Among the examined variations, seven weeks of cold temperatures (8°C day and 5°C night) proved to be the optimal for flowering (100%). Shorter periods of cold temperatures (1–2 weeks) or higher temperature regimes (15°C day and 10°C night) induced only partial flowering (18–80%). Root stocks with a diameter below 8 mm seem to require longer vernalization. Morphological characteristics of the flowers were also affected by temperatures and photoperiod. Short day treatments (4 weeks of 10 h day and 14 h night) did not initiate flowering. The studied genotypes of biennial caraway all had similar reactions.