E-mail: banyai.judit@atk.hun-ren.hu

Over the last two decades various high-throughput phenotyping techniques have been developed, which can be used in wheat breeding, genetic analysis and model compilation for the study of disease resistance, drought and heat tolerance. The long-range spectroscopic measurements are a huge help in examining the field areas observed by breeders in minutes, enabling the recording of coordinate-location data in seconds.

Because drones, thanks to their flexibility, under the right conditions, are able to fly and hover above the given area, they are suitable for carrying out plot data recordings. With this high-throughput phenotyping system, changes occurring in experiments involving up to thousands of plots can be easily monitored, and by analyzing the huge amount of data that can be collected in one growing season, species-specific plant models can also be created from germination to ripening.

By using drones, the breeder's selection process can be simplified, accelerated and made mo

re objective, and the use of multispectral imaging sensor systems allows access to information that is not visible to the naked eye. So multi or hyperspectral imaging of a plant is more than 'photography'. The goal is none other than the quantitative measurement of the examined phenotypic properties through the interactions between light (reflected, absorbed, transmitted photons) and the plant.

Drone flights have been carried out at the Agricultural Institute, Cereal Breeding Department, Martonvásár, Hungary, since 2019. In addition, in autumn 2021 and 2022, an expanded reference variety trial was established, consisting of 11 winter wheat, barley, durum wheat and triticale genotypes, which are susceptible and/or tolerant to disease, drought and heat stress.

The trial was artificially inoculated with leaf rust and additionally with Pyrenophora teres f. maculata in case of barley. Four out of eight randomly arranged replications were treated with fungicide. In each growing season the drone flew from spring onwards weekly over the plots at a height of 100 meters.

Altogether, 17 phenotypic parameters were recorded, 47 spectral data were measured by the drone on 12 occasions, and all plots were harvested in the summer. The orthophotos show whether there is soil patches in the experimental area, how the field is covered with vegetation, the development of the plant population, whether there is weeding or wildlife damage.The emergence of individual plant diseases can be tracked, and infection hotspots can be detected linked to the corresponding GPS and vegetation index data. Our goal is to identify the spectral bands and indices that offer the greatest differences between genotypes, and to show, already at an early stage of development, that a change has occurred in the physiological processes of the examined line.

Acknowledgements

Project TKP2021-NKTA-06 has been implemented with the support provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NKTA funding scheme.