Spectral analysis of the phenological stages of Lupinus mutabilis through spectroradiometry and unmanned aerial vehicle imaging with different physical disinfection pretreatments of seeds

The economic and cultural importance of lupin has been identified in regions such as the alpine zone of Ecuador, where per capita consumption reaches 0.4 kg per month. However, fungal pathogens affect lupin cultivation, causing considerable crop losses. In this study, Lupinus mutabilis Sweet plants started from seeds were analysed using remote sensing techniques, and different physical disinfection pretreatments were applied. A total of 6 samplings were conducted according to the phenological stages of the crop. A spectroradiometer and an unmanned aerial vehicle were used to generate vegetation indices based on the red, near-infrared and red-edge bands. Using SfM photogrammetry and RTK positioning, the vegetation index values were extracted from the orthophotos and statistically analysed. All the vegetation indices exhibited significant differences between phenological stages, but the differences between pretreatments were not as clear. The best pretreatment was determined to be drying the seeds at ambient temperature for 45 minutes.