Non-Destructive Optical Monitoring of Grape Maturation by Proximal Sensing

Ghozlen, Naïma Ben; Cerović, Zoran G.; Germain, Claire; Toutain, S.; Latouche, Gwendal

doi:10.3390/s101110040

Cited by 189 publications

(200 citation statements)

References 34 publications

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“…Those had a quite good correlation of 0.699 and 0.674, respectively [12]. Moreover, previous researchers also succeeded in promoting the chlorophyll fluorescence technique as a non-destructive evaluation for flavonols and anthocyanins in grapes [13].…”

Section: Potential Maturity Indices In Satsuma Mandarinmentioning

confidence: 87%

Monitoring of Fluorescence Characteristics of Satsuma Mandarin (Citrus unshiu Marc.) during the Maturation Period

et al. 2017

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Abstract:Monitoring the maturation process of Satsuma mandarin (Citrus unshiu Marc.) by determining the soluble solids (SS) and acid content non-destructively is needed. Fluorescence components potentially offer such means of accessing fruit maturity characteristics in the orchard. The aim of this study was to determine the potential of fluorescence spectroscopy for monitoring the stage of citrus maturity. Four major fluorescent components in peel and/or flesh were found including chlorophyll-a (excitation (Ex) 410 nm, emission (Em) 675 nm) and chlorophyll-b (Ex 460 nm, Em 650 nm),polymethoxyflavones (PMFs) (Ex 260 nm and 370 nm, Em 540 nm), coumarin (Ex 330 nm, Em 400 nm), and a tryptophan-like compound (Ex 260 nm, Em 330 nm). Our results indicated a significant (R 2 = 0.9554) logarithmic ratio between tryptophan-like compoundsExEm and chlorophyll-aExEm with the SS:acid ratio. Also, the log of the ratio of PMFs from the peel (ExExEm was significantly correlated with the SS:acid ratio (R 2 = 0.8207). While the latter correlation was not as strong as the former, it does demonstrate the opportunity to develop a non-destructive field measurement of fluorescent peel compounds as an indirect index of fruit maturity.

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Section: Potential Maturity Indices In Satsuma Mandarinmentioning

confidence: 87%

Monitoring of Fluorescence Characteristics of Satsuma Mandarin (Citrus unshiu Marc.) during the Maturation Period

et al. 2017

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“…Three detectors are measuring the emitted fluorescence at the wavelengths of blue, red and far-red light. Ghozlen et al [46] and Cerovic et al [47] provide a more detailed description of the sensor. Table 2 gives an overview of the different ratios measured by the Multiplex R sensor.…”

Section: Multiplexmentioning

confidence: 99%

Using Optical Sensors to Identify Water Deprivation, Nitrogen Shortage, Weed Presence and Fungal Infection in Wheat

et al. 2016

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Abstract:The success of precision agriculture relies largely on our ability to identify how the plants' growth limiting factors vary in time and space. In the field, several stress factors may occur simultaneously, and it is thus crucial to be able to identify the key limitation, in order to decide upon the correct contra-action, e.g., herbicide application. We performed a pot experiment, in which spring wheat was exposed to water shortage, nitrogen deficiency, weed competition (Sinapis alba L.) and fungal infection (Blumeria graminis f. sp. tritici) in a complete, factorial design. A range of sensor measurements were taken every third day from the two-leaf stage until booting of the wheat (BBCH 12 to 40). Already during the first 10 days after stress induction (DAS), both fluorescence measurements and spectral vegetation indices were able to differentiate between non-stressed and stressed wheat plants exposed to water shortage, weed competition or fungal infection. This meant that water shortage and fungal infection could be detected prior to visible symptoms. Nitrogen shortage was detected on the 11-20 DAS. Differentiation of more than one stress factors with the same index was difficult.

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“…The fluorometer measurements resulted in a suite of indices from various combinations of the activation and detection wavelengths used (e.g. Ghozlen et al 2010), as shown in Table 2. Measurements were made to target the heads and top of the wheat canopy.…”

Section: Active Light Fluorometermentioning

confidence: 99%

“…A strong correlation (r = -0.87) was found between Fv/Fm measurements made immediately after exposure to À128C, and visual scoring of frost damage in the field for the corresponding cultivars tested. Wu et al (2012) used a handheld active light fluorometer to measure a nitrogen balance index (NBI_G; Ghozlen et al 2010) for potted wheat seedlings exposed to freezing temperatures, and assessed by visual inspection of apparent damage. With accumulation of freezing events, the NBI_G values actually increased, rather that decreased as would be expected.…”

Section: Previous Researchmentioning

confidence: 99%

In-field methods for rapid detection of frost damage in Australian dryland wheat during the reproductive and grain-filling phase

Perry¹,

Nuttall²,

Wallace³

et al. 2017

Crop Pasture Sci.

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Abstract. Frost damage causes significant production losses and costs to Australian dryland wheat, and frost impacts are not expected to decline in the near future, despite global warming. Rapid estimation of frost damage to crops on a spatial basis would allow for timely management decisions to reduce the economic impact of frost events. In this paper, we take a first step in evaluating the utility of hyperspectral reflectance and active light fluorescence for detecting frost damage to wheat during its reproductive phase. Two experiments were conducted immediately after the first observation of frost damage, (i) in 2006, five plots in an existing trial were opportunistically subdivided to take spectral reflectance measurements on frost damaged plants along with yield measurements, and (ii) in 2015, a transect across 31 rows within a commercial paddock was established to evaluate spectral reflectance, fluorometer measurements, and yield along a gradient from non-frosted to frost damaged plants. The results of the hyperspectral reflectance data appeared variable in response across the two experimental sites where frost was observed in-crop. In 2006, hyperspectral-derived indices showed significant differences (P < 0.05) between measurements of frosted and non-frosted canopies, but this was not the case for observations taken in 2015, where the mean response was reversed between experimental sites for several of the indices. In contrast, fluorometer measurements in the 2015 trial resulted in higher correlations with yield and observed frost damage compared with the reflectance measurements. Seven of the nine fluorometer indices evaluated were correlated with yield (used as an indicator of frost damage) at P < 0.01. An index of compounds which absorbs at 375 nm, FLAV, had the best correlation coefficients of 0.91 and 0.90 for the two dates in 2015. The fluorescence index FLAV was selected to evaluate whether it could be used to classify the canopy as frost affected or not, using discriminant analysis for the 2015 transect data. The overall classification accuracy, defined as the number of correctly classified measurements (57) divided by the total number (62) was 92%. The present study was not able to provide insight into how rapidly the sensors could detect frost damage before detection with the naked eye, as the survey data constituted a transect based on early visual symptoms, however this study does provide important insight into what sensors and/or indices may be sensitive to 'seeing' early frost damage in-crop. The next steps, which build on this work and need to be resolved are (i) what is the nominal scale of measurements required, and for which portions of the plant canopy? (ii) How robust (over space and time) are any relationships between frost damage and index response? (iii) Can frost damage be detected before the onset of visual damage?

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Non-Destructive Optical Monitoring of Grape Maturation by Proximal Sensing

Cited by 189 publications

References 34 publications

Monitoring of Fluorescence Characteristics of Satsuma Mandarin (Citrus unshiu Marc.) during the Maturation Period

Monitoring of Fluorescence Characteristics of Satsuma Mandarin (Citrus unshiu Marc.) during the Maturation Period

Using Optical Sensors to Identify Water Deprivation, Nitrogen Shortage, Weed Presence and Fungal Infection in Wheat

In-field methods for rapid detection of frost damage in Australian dryland wheat during the reproductive and grain-filling phase

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