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Hyperspectral and thermal imaging of oilseed rape (Brassica napus) response to fungal species of the genus Alternaria.

Baranowski P, Jedryczka M, Mazurek W, Babula-Skowronska D, Siedliska A, Kaczmarek J - PLoS ONE (2015)

Bottom Line: The measurements of disease severity for chosen dates after inoculation were compared to temperature distributions on infected leaves and to averaged reflectance characteristics.Statistical analysis revealed that leaf temperature distributions on particular days after inoculation and respective spectral characteristics, especially in the SWIR range (1000-2500 nm), significantly differed for the leaves inoculated with A. dauci from the other species of Alternaria as well as from leaves of non-treated plants.The second-derivative transformation of the spectral data together with back-propagation neural networks (BNNs) appeared to be the best combination for classification of days after inoculation (prediction accuracy 90.5%) and Alternaria species (prediction accuracy 80.5%).

View Article: PubMed Central - PubMed

Affiliation: Institute of Agrophysics, Polish Academy of Sciences, Lublin, Poland.

ABSTRACT
In this paper, thermal (8-13 µm) and hyperspectral imaging in visible and near infrared (VNIR) and short wavelength infrared (SWIR) ranges were used to elaborate a method of early detection of biotic stresses caused by fungal species belonging to the genus Alternaria that were host (Alternaria alternata, Alternaria brassicae, and Alternaria brassicicola) and non-host (Alternaria dauci) pathogens to oilseed rape (Brassica napus L.). The measurements of disease severity for chosen dates after inoculation were compared to temperature distributions on infected leaves and to averaged reflectance characteristics. Statistical analysis revealed that leaf temperature distributions on particular days after inoculation and respective spectral characteristics, especially in the SWIR range (1000-2500 nm), significantly differed for the leaves inoculated with A. dauci from the other species of Alternaria as well as from leaves of non-treated plants. The significant differences in leaf temperature of the studied Alternaria species were observed in various stages of infection development. The classification experiments were performed on the hyperspectral data of the leaf surfaces to distinguish days after inoculation and Alternaria species. The second-derivative transformation of the spectral data together with back-propagation neural networks (BNNs) appeared to be the best combination for classification of days after inoculation (prediction accuracy 90.5%) and Alternaria species (prediction accuracy 80.5%).

No MeSH data available.


Related in: MedlinePlus

Thermal images of oilseed rape leaves inoculated with Alternaria brassicae after 3 (left) and 7 (right) d after inoculation (dai) with selected areas representing analysed leaf surfaces (temperature values in the legend in °C). Below, a histogram of temperature distribution of the leaves for these two days.Areas of the leaves used for histogram construction (two leaves for 3 dai and one leaf for 7 dai) are shown selected with polygon line.
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pone.0122913.g002: Thermal images of oilseed rape leaves inoculated with Alternaria brassicae after 3 (left) and 7 (right) d after inoculation (dai) with selected areas representing analysed leaf surfaces (temperature values in the legend in °C). Below, a histogram of temperature distribution of the leaves for these two days.Areas of the leaves used for histogram construction (two leaves for 3 dai and one leaf for 7 dai) are shown selected with polygon line.

Mentions: The temperature distributions of infected and control leaves were analysed by selecting leaf areas in each thermal image with the use of the polygon area selection tool of the ThermaCAM Researcher software. Fig 2 shows exemplary images of oilseed rape leaves inoculated with A. brassicae 3 and 7 d after inoculation. On the third day after inoculation, the average leaf temperature was higher than on the seventh day, and the range of temperatures was much lower. The histogram obtained for the results of 7 d after inoculation shows an increased range of temperatures and a lower temperature median. The infected parts of leaves on day 7 are manifested as irregular areas of temperatures lower than the rest of the leaf.


Hyperspectral and thermal imaging of oilseed rape (Brassica napus) response to fungal species of the genus Alternaria.

Baranowski P, Jedryczka M, Mazurek W, Babula-Skowronska D, Siedliska A, Kaczmarek J - PLoS ONE (2015)

Thermal images of oilseed rape leaves inoculated with Alternaria brassicae after 3 (left) and 7 (right) d after inoculation (dai) with selected areas representing analysed leaf surfaces (temperature values in the legend in °C). Below, a histogram of temperature distribution of the leaves for these two days.Areas of the leaves used for histogram construction (two leaves for 3 dai and one leaf for 7 dai) are shown selected with polygon line.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4380467&req=5

pone.0122913.g002: Thermal images of oilseed rape leaves inoculated with Alternaria brassicae after 3 (left) and 7 (right) d after inoculation (dai) with selected areas representing analysed leaf surfaces (temperature values in the legend in °C). Below, a histogram of temperature distribution of the leaves for these two days.Areas of the leaves used for histogram construction (two leaves for 3 dai and one leaf for 7 dai) are shown selected with polygon line.
Mentions: The temperature distributions of infected and control leaves were analysed by selecting leaf areas in each thermal image with the use of the polygon area selection tool of the ThermaCAM Researcher software. Fig 2 shows exemplary images of oilseed rape leaves inoculated with A. brassicae 3 and 7 d after inoculation. On the third day after inoculation, the average leaf temperature was higher than on the seventh day, and the range of temperatures was much lower. The histogram obtained for the results of 7 d after inoculation shows an increased range of temperatures and a lower temperature median. The infected parts of leaves on day 7 are manifested as irregular areas of temperatures lower than the rest of the leaf.

Bottom Line: The measurements of disease severity for chosen dates after inoculation were compared to temperature distributions on infected leaves and to averaged reflectance characteristics.Statistical analysis revealed that leaf temperature distributions on particular days after inoculation and respective spectral characteristics, especially in the SWIR range (1000-2500 nm), significantly differed for the leaves inoculated with A. dauci from the other species of Alternaria as well as from leaves of non-treated plants.The second-derivative transformation of the spectral data together with back-propagation neural networks (BNNs) appeared to be the best combination for classification of days after inoculation (prediction accuracy 90.5%) and Alternaria species (prediction accuracy 80.5%).

View Article: PubMed Central - PubMed

Affiliation: Institute of Agrophysics, Polish Academy of Sciences, Lublin, Poland.

ABSTRACT
In this paper, thermal (8-13 µm) and hyperspectral imaging in visible and near infrared (VNIR) and short wavelength infrared (SWIR) ranges were used to elaborate a method of early detection of biotic stresses caused by fungal species belonging to the genus Alternaria that were host (Alternaria alternata, Alternaria brassicae, and Alternaria brassicicola) and non-host (Alternaria dauci) pathogens to oilseed rape (Brassica napus L.). The measurements of disease severity for chosen dates after inoculation were compared to temperature distributions on infected leaves and to averaged reflectance characteristics. Statistical analysis revealed that leaf temperature distributions on particular days after inoculation and respective spectral characteristics, especially in the SWIR range (1000-2500 nm), significantly differed for the leaves inoculated with A. dauci from the other species of Alternaria as well as from leaves of non-treated plants. The significant differences in leaf temperature of the studied Alternaria species were observed in various stages of infection development. The classification experiments were performed on the hyperspectral data of the leaf surfaces to distinguish days after inoculation and Alternaria species. The second-derivative transformation of the spectral data together with back-propagation neural networks (BNNs) appeared to be the best combination for classification of days after inoculation (prediction accuracy 90.5%) and Alternaria species (prediction accuracy 80.5%).

No MeSH data available.


Related in: MedlinePlus