Micropropagation affects tree architecture of two olive cultivars: a field evaluation

ISHS Secretariat
Micropropagation affects tree architecture of two olive cultivars: a field evaluation

As part of his PhD at the Department of Soil, Plant and Food Sciences, University of Bari Aldo Moro, Italy, Francesco Maldera is evaluating the behavior of new hedgerow systems in olive and almond orchards. This research is exploring the relevance of propagation methods for olive trees and how the in vitro propagation techniques affect the morphology and architectural parameters of different olive cultivars and thus their suitability in orchard intensification. The aim of this study was to observe the impact of different propagation methods on the shooting dynamics of two olive cultivars, ‘Arbequina’ and ‘Coratina’, in a super high-density orchard. The research was conducted in an experimental olive orchard in Apulia, southern Italy. Micropropagation (micro) and mist propagation (auto) techniques were compared. Measurements were taken to analyze growth, internodal length and the number of nodes, to understand how they affect the growth and architecture of olive trees. Micropropagation had a significant effect on the apical sprout growth of ‘Coratina’ compared to auto, resulting in longer internodes with the same amount of nodes. In ‘Arbequina’, no significant differences were observed in apical sprout growth between the two propagation methods. However, shorter internodes were observed in micropropagated trees. An analysis of the branching model revealed differences in the shoot architecture between the cultivars and propagation methods. ‘Arbequina’ showed an acrotonic gradient with sprouts developing from the upper part of the shoot, whereas ‘Coratina’ exhibited a proleptic shoot branching pattern, where sprouts appeared linearly relative to the apical sprout. Micropropagation led to more lateral sprouts with strong branching in ‘Coratina’. Overall, the study finds that micropropagation does not significantly impact the vegetative dynamics of ‘Arbequina’ but negatively affects the shoot dynamics of ‘Coratina’. These findings suggest that new low-vigor cultivars may benefit from micropropagation techniques. However, further studies are needed to better understand the behavior of newly introduced low-vigor cultivars and to optimize propagation methods for different olive varieties in super high-density orchards.

Francesco Maldera won the ISHS Young Minds Award for the best oral presentation at the I International Symposium on Plant Propagation, Nursery Organization and Management for the Production of Certified Fruit Trees in Italy in July 2023.

Francesco Maldera, Department of Soil, Plant and Food Sciences, Università degli studi di Bari Aldo Moro, Bari 70126 (Puglia), Italy, e-mail: francesco.maldera@uniba.it

The article is available in Chronica Horticulturae

tree architecture
Young Minds Award Winners