Identification of citrus varieties using laser-induced fluorescence spectroscopy (LIFS)

• LIF spectroscopy was used to discriminate different varieties citrus.
• Spectral differences were found among the different canopies and also between the two rootstocks assessed.
• High accuracy was obtained with the technique presented to classify the varieties.
• These results can be used in the development of a quick and economically viable method for seedling certification.

The production of sweet orange faces a problem with regard to visually identifying citrus seedling varieties. Despite using analytical techniques such as molecular markers, this kind of classification is not possible due to very subtle genetic variations. This is an important fact given that the cultivation of a variety that differs from the one planned can cause numerous serious problems, such as the treatments applied to the orchards as well as the quality and characteristics of the fruits after harvest. Within this context, we assess the laser-induced fluorescent emission technique (LIFS) as a tool to identify citrus varieties. The results showed that LIFS combined with statistical methods is able to discriminate the different citrus varieties chosen. The rate of success for this classification depends on the combination of canopy and rootstock varieties, and our best result was of around 100%. These results can be used in the development of a new method that is economically viable for seedling certification.