Tree crown parameters assessment using 3D photo reconstruction as a tool for selection in olive breeding programs

Abstract

In olive, both discontinuous canopy (open vase configuration) and continuous canopy (hedgerow) systems are used in commercial planting. Reliable and cost effective plant architecture characterization is necessary to test the suitability of cultivars to specific growing systems, particularly in olive breeding programs where a large number of genotypes must be evaluated. In this work, the performance of a method for the estimation of olive tree height and crow diameter based on low cost unmanned aerial vehicle (UAV) imagery was evaluated. Selections from breeding programs cultivated either on discontinuous or continuous canopy cropping systems were used for developing the models. Averaged data by genotypes showed significant linear fits between reference field measurements and remote sensing estimation of crown parameters with R2 values of 0.89 for height estimation in hedgerow plantations, 0.66 and 0.53 for crown diameter in discontinuous canopy and continuous hedgerows respectively, but only 0.14 between measured and estimated height in discontinuous canopy genotypes. These results indicate that low cost UAV imagery could be used for evaluating olive tree crown parameters (tree height and crown diameter) in olive breeding programs, providing accurate enough results for selection of genotypes.