Mid-infrared spectroscopy combined with chemometrics to detect Sclerotinia stem rot on oilseed rape ( Brassica napus L.) leaves.

Abstract

Background Detection of plant diseases in a fast and simple way is crucial for timely disease control. Conventionally, plant diseases are accurately identified by DNA, RNA or serology based methods which are time consuming, complex and expensive. Mid-infrared spectroscopy is a promising technique that simplifies the detection procedure for the disease. Mid-infrared spectroscopy was used to identify the spectral differences between healthy and infected oilseed rape leaves. Two different sample sets from two experiments were used to explore and validate the feasibility of using mid-infrared spectroscopy in detecting Sclerotinia stem rot (SSR) on oilseed rape leaves. Results The average mid-infrared spectra showed differences between healthy and infected leaves, and the differences varied among different sample sets. Optimal wavenumbers for the 2 sample sets selected by the second derivative spectra were similar, indicating the efficacy of selecting optimal wavenumbers. Chemometric methods were further used to quantitatively detect the oilseed rape leaves infected by SSR, including the partial least squares-discriminant analysis, support vector machine and extreme learning machine. The discriminant models using the full spectra and the optimal wavenumbers of the 2 sample sets were effective for classification accuracies over 80%. The discriminant results for the 2 sample sets varied due to variations in the samples. Conclusion The use of two sample sets proved and validated the feasibility of using mid-infrared spectroscopy and chemometric methods for detecting SSR on oilseed rape leaves. The similarities among the selected optimal wavenumbers in different sample sets made it feasible to simplify the models and build practical models. Mid-infrared spectroscopy is a reliable and promising technique for SSR control. This study helps in developing practical application of using mid-infrared spectroscopy combined with chemometrics to detect plant disease.

Plant phenotyping relevance

油糧ナタネ葉の感染状態という植物病害表現型を、中赤外分光とケモメトリクスで検出する方法を開発・検証しており、方法論が研究の中心である。

Code and data availability

The paper reports mid-infrared spectra of healthy and Sclerotinia-infected oilseed rape leaves and chemometric models (PLS-DA, SVM, ELM), but no public dataset, spectra, code, or models are deposited. The only availability statement directs readers to contact the corresponding author, so any paper-specific asset would需

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