2019 ASHS Annual Conference

‘UCB-1’ is currently the most commonly used pistachio rootstock in California but it varies because it is a population of F1 seedlings from a cross between two heterozygous outbreeding species. Phenotyping of large orchard populations is labor inefficient and expensive. High-throughput phenotyping (HTP) using drones allows analysis of many genotypes in multiple locations. A DJI Matrice 100 drone, equipped with both a conventional DJI X3 12 MP red-green-blue (RGB) camera and a Micasense RedEdge multispectral (blue, green, red, red edge, and near infrared) imager was flown over a 3.5 acre experimental pistachio orchard at UC Davis’s Russell Ranch multiple times during 2018. Tree height and canopy volume of 480 five year old UCB-1 seedlings were recorded. These flights were conducted at an altitude of 30 meters above ground level, using a pre-planned crosshatched (grid) autonomous flight plan, with the cameras set to trigger along the drone’s path such that each picture would have an approximately 90% overlap with each adjacent picture. The resulting RGB orthomosaics were found to have a spatial resolution (ground sample distance) of approximately 1.5 cm, and the multispectral imagery a spatial resolution of 1.8 cm. This HTP reduced measurement error and facilitated the determination of dynamic traits such as tree height and canopy volume.