Phenological, morphological and functional indicators of genetic variability and their implication in the sexual reproductive system of Olea europaea L. (Oleaceae)

The floral biology of ‘Koroneiki’, ‘Kalamata’ and ‘Mastoidis’ was studied for three consecutive years to elucidate the potential physiological and genetic controls of inflorescence architecture and phenology and to identify potential genotype-distinguishing characters that could be employed for morphological cultivar discrimination. The first open flowers were mainly observed at position I for ‘Koroneiki’ (83%) while they were mainly located at position II for ‘Mastoidis’ (40%) and ‘Kalamata’ (63%). The last open flowers were principally located at the apical position for ‘Koroneiki’ (46%) and ‘Kalamata’ (68%) and at position II for ‘Mastoidis’ (75%). Most of the first open flowers were perfect for ‘Koroneiki’ (89%) and ‘Mastoidis’ (97%) while lower percentages were observed in the last open flowers (67% and 80%, respectively). Higher percentages of perfect flowers were observed in ‘Mastoidis’ compared to ‘Koroneiki’ in both cases. The average flowering shoots of ‘Kalamata’ produced significantly more flowers (1523/m) compared to ‘Koroneiki’ (1139/m) and ‘Mastoidis’ (1044/m). The half of the flowers in ‘Mastoidis’ were located at position I while the 38% was located at position II and only the 12% at the apex. By contrast, approximately the 80% of flowers in ‘Koroneiki’ and ‘Kalamata’ panicles was equally distributed at positions I and II, while the 18% and 19%, respectively, was located at the apex. A marked relationship was also observed between flower position in the panicle and flower gender.