Shoot growth pattern and return bloom of six olive varieties in response to cultivation practices stimulating or limiting the vegetative growth in young trees

Abstract

Olive trees show a very marked alternate bearing behavior. Generally, this behavior is regulated by the balance between growth of vegetative and reproductive organs. A high fruit load can negatively affect the elongation of 1-year-old mixed shoots and lead to decreased production of new potential reproductive buds in the following year. Applied nutrients and water availability can also affect new shoot growth, yet, the best period for vegetative growth and bud induction is unclear. In this study we investigated growth pattern of the vegetative portion of 1-year-old mixed shoots (year n) and the return bloom in the following year (n + 1) in six olive cultivars under “strong” and “weak” vegetative growth practices. Results found that in the following year the number of inflorescences on 1-year-old mixed shoots was affected as a consequence of the different level of vegetative growth. In addition to the greater vegetative growth of 1-year-old mixed shoots, the number of sylleptic shoots also seemed to be influenced by cultivation practices. Moreover, sylleptic shoots had more inflorescences per bud than the 1-year-old shoots. The nodes of the 1-year-old mixed shoots that grew during June and July produced the majority of inflorescences per bud compared to the nodes that grew during spring and late summer.