Discrimination of Genetically Very Close Accessions of Sweet Orange ( Citrus sinensis L. Osbeck) by Laser-Induced Breakdown Spectroscopy (LIBS).

Abstract

The correct recognition of sweet orange ( Citrus sinensis L. Osbeck) variety accessions at the nursery stage of growth is a challenge for the productive sector as they do not show any difference in phenotype traits. Furthermore, there is no DNA marker able to distinguish orange accessions within a variety due to their narrow genetic trace. As different combinations of canopy and rootstock affect the uptake of elements from soil, each accession features a typical elemental concentration in the leaves. Thus, the main aim of this work was to analyze two sets of ten different accessions of very close genetic characters of three varieties of fresh citrus leaves at the nursery stage of growth by measuring the differences in elemental concentration by laser-induced breakdown spectroscopy (LIBS). The accessions were discriminated by both principal component analysis (PCA) and a classifier based on the combination of classification via regression (CVR) and partial least square regression (PLSR) models, which used the elemental concentrations measured by LIBS as input data. A correct classification of 95.1% and 80.96% was achieved, respectively, for set 1 and set 2. These results showed that LIBS is a valuable technique to discriminate among citrus accessions, which can be applied in the productive sector as an excellent cost-benefit tool in citrus breeding programs.

Plant phenotyping relevance

LIBSによる葉の元素濃度測定と分類モデルを用い、近縁カンキツ系統を識別する手法を検証・適用しており、元素濃度という植物状態の取得・解析が研究の中心である。

Code and data availability

The article describes LIBS spectral measurements of sweet orange leaves and PCA/CVR-PLSR analysis, but contains no public phenotype dataset, spectra deposit, author code, or model release. The only URL mentioned (NIST LIBS database) is a generic reference tool, not a paper-specific asset. No data or code availability/`

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