Fruitlet abscission in olive (Olea europaea L.)

Despite profuse flowering, olive (Olea europaea L.) yields are low because of excessive fruitlet abscission. Only 1-3% of the flowers develop into mature fruit. We studied the role of flower position within an inflorescence as well as the effect of flower removal on fruitlet abscission in ‘Barnea’. Various flower removal treatments, with or without the removal of all other inflorescences on the branch, were carried out and mature fruit development was recorded. Of 540 flowers examined, about 44% were staminate and 66% hermaphroditic. We found that the lateral flowers within an inflorescence tend to be staminate. Flower removal of at least 50% of the flower within inflorescence, delayed abscission from day 20 after anthesis to day 30. The developed fruits were not necessarily those of flowers which opened earliest. Flowers at position 1 (apical) and 5T (terminal) were more likely to develop into fruits compared to those at other positions within the inflorescence. Removing all inflorescences on a branch except one significantly increased the number of fruits from 1.28 to 2.79 fruits per inflorescence. Removing only the lateral flowers increased the number of fruits from 1.28 to 1.58 fruits per inflorescence, but this increase was not considered significant. These preliminary results highlight the need for further research aimed at increasing the percentage of developed fruits per inflorescence.