A Reliable Method to Recognize Soybean Seed Maturation Stages Based on Autofluorescence-Spectral Imaging Combined With Machine Learning Algorithms

Thiago Barbosa Batista; Clíssia Barboza Mastrangelo; André Dantas de Medeiros; Ana Carolina Picinini Petronilio; Gustavo Roberto Fonseca de Oliveira; Isabela Lopes Dos Santos; Carlos Alexandre Costa Crusciol; Edvaldo Aparecido Amaral da Silva

doi:10.3389/fpls.2022.914287

A Reliable Method to Recognize Soybean Seed Maturation Stages Based on Autofluorescence-Spectral Imaging Combined With Machine Learning Algorithms

Front Plant Sci. 2022 Jun 14:13:914287. doi: 10.3389/fpls.2022.914287. eCollection 2022.

Authors

Thiago Barbosa Batista¹, Clíssia Barboza Mastrangelo², André Dantas de Medeiros³, Ana Carolina Picinini Petronilio¹, Gustavo Roberto Fonseca de Oliveira¹, Isabela Lopes Dos Santos¹, Carlos Alexandre Costa Crusciol¹, Edvaldo Aparecido Amaral da Silva¹

Affiliations

¹ Department of Crop Science, College of Agricultural Sciences, São Paulo State University, Botucatu, Brazil.
² Laboratory of Radiobiology and Environment, Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, Brazil.
³ Department of Agronomy, Federal University of Viçosa, Viçosa, Brazil.

Abstract

In recent years, technological innovations have allowed significant advances in the diagnosis of seed quality. Seeds with superior physiological quality are those with the highest level of physiological maturity and the integration of rapid and precise methods to separate them contributes to better performance in the field. Autofluorescence-spectral imaging is an innovative technique based on fluorescence signals from fluorophores present in seed tissues, which have biological implications for seed quality. Thus, through this technique, it would be possible to classify seeds in different maturation stages. To test this, we produced plants of a commercial cultivar (MG/BR 46 "Conquista") and collected the seeds at five reproductive (R) stages: R7.1 (beginning of maturity), R7.2 (mass maturity), R7.3 (seed disconnected from the mother plant), R8 (harvest point), and R9 (final maturity). Autofluorescence signals were extracted from images captured at different excitation/emission combinations. In parallel, we investigated physical parameters, germination, vigor and the dynamics of pigments in seeds from different maturation stages. To verify the accuracy in predicting the seed maturation stages based on autofluorescence-spectral imaging, we created machine learning models based on three algorithms: (i) random forest, (ii) neural network, and (iii) support vector machine. Here, we reported the unprecedented use of the autofluorescence-spectral technique to classify the maturation stages of soybean seeds, especially using the excitation/emission combination of chlorophyll a (660/700 nm) and b (405/600 nm). Taken together, the machine learning algorithms showed high performance segmenting the different stages of seed maturation. In summary, our results demonstrated that the maturation stages of soybean seeds have their autofluorescence-spectral identity in the wavelengths of chlorophylls, which allows the use of this technique as a marker of seed maturity and superior physiological quality.

Keywords: Glycine max; chlorophyll fluorescence; seed maturity; seed quality; support vector machine.