Relationships between flower density and shoot length in hazelnut (Corylus avellana L.)

High flower density is a prerequisite to obtain high yield. Considering that flower induction occurs simultaneously with shoot growth, shoot length could influence shoot flower abundance. Previous studies reported that nuts were borne in the apical part of the canopy on long shoots. But no data have been reported about possible relationship between flower density and shoot length. The aim of the present work was to assess whether flower density is related to shoot length in Corylus avellana L. Shoot morphological characteristics, flower number and flower sex was studied in two of the main cultivars of C. avellana. Female flowers were generally borne in apical long shoots. Shoot length was negatively correlated with flower density even though different behavior was observed between cultivars. Maximum estimated probabilities of shoot flowering varied between cultivars. These results suggest that flower density can be influenced by shoot length. Genotype can also affect such relationship. Flower density appeared to decrease in longest shoots in hazelnut. The effect of genotype on flower density may explain variation of productivity between cultivars.