High-throughput analysis of the canopy traits in the worldwide olive germplasm bank of Córdoba using very high-resolution imagery acquired from unmanned aerial vehicle (UAV)

The characterization of tree canopy traits represents a key step to identify potential cultivars adaptable to a specific growing system. Developing methodologies to rapidly evaluate canopy traits allows to classify cultivars in germplasm banks and facilitates selections in breeding programs. In the present work, the ability of low-cost unmanned aerial vehicle (UAV) was compared with on-ground traditional methodology for measuring canopy traits (namely crown diameters, tree height and crown volume) in trees of the Worldwide Olive Germplasm Bank of Córdoba. The evaluated trees belonged to a wide range of cultivars and were planted in three different dates. A wide variability was found for the four parameters measured with both on ground and UAV methodologies. Besides, a significant linear correlation was observed at tree and cultivar level, with relative errors that ranged from 4.44 to 13.9 % for axial parameters or from 17.0–29.0% for volume, depending on the planting date considered. ANOVA and Tukey's results showed a high agreement between both methodologies in identifying cultivars with similar vigour values. When comparing means over time, the UAV-based data allowed a slightly better detection of significant differences than on-ground data. The results provided by the present research indicated that the use of UAV is a reliable methodology to study tree canopy traits in olive germplasm banks, supporting breeders to the identification and definition of the genetics behind crop variability. The evaluation here performed indicates that there is a wide variability on canopy traits on the cultivated olive germplasm that could be exploited to select potential cultivars for different growing systems.

The WOGBC-IFAPA has been maintained by different national projects (RFP 2013-00005-00-00 and RFP 2017-00007-00-00) funded by INIA as well as by project PR.CRF.CRF2019.004 partly funded by the European Agricultural Fund for Rural Development (EAFRD).

Peer reviewed