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Carlos Campillo, M.I. García, C. Daza, and M.H. Prieto

, although with differences in the adjustment (0.89 and 0.93 for 2005 and 2006, respectively). In this case, a single curve would have enabled us to estimate the LAI by nondestructive methods using digital images. Although, in principle, the factors that can

Open access

Steven H. Schwartzkopf

Abstract

In the past, plant growth generally has been measured using destructive methods. This paper describes a nondestructive technique for continuously monitoring plant growth. The technique provides a means of directly and accurately measuring plant growth over both short and long time intervals. Application of this technique to the direct measurement of plant growth rates is illustrated using corn (Zea mays L.) as an example.

Open access

George J. Wulster

Abstract

In the article “A Nondestructive Method for Measuring Root System Surface Area” by George J. Wulster (HortScience 20:1058–1060, Dec. 1985), the author requests that the following correction be noted: The 3rd line under Gel Construction on p. 1058 should be changed from “… HHR (0.65gm/l) was added slowly to 2 liters … ” to “… HHR (0.65 gm/100 ml) was added slowly to 2 liters …”.

Open access

George J. Wulster

Abstract

A method is described for obtaining nondestructive estimates of root system surface area. The technique is based on the assumption that the larger the root system, the more gel of a given viscosity will adhere to it. The correlation between gel adherence and 5 parameters of root system size (root length, root fresh weight, root dry weight, root volume, and root surface area) is established.

Free access

Judith A. Abbott and Louis A. Liljedahl

Sonic vibrational characteristics of intact apples are related to flesh elasticity which is, in turn, related to firmness. Firmness changes in Golden Delicious and Delicious apples were followed during accelerated ripening and under storage conditions. Firmness was measured by Magness-Taylor puncture force and by compression of tissue cylinders (modulus of elasticity and rupture strength) for comparison with sonic vibrational characteristics of intact apples. Influences of apple temperature, size, shape, and skin on sonic spectra were investigated. Sonic resonant frequencies were significantly correlated with destructive firmness measurements and decreased as storage time increased. Sonic amplitudes were not closely related to firmness. Regression equations incorporating sonic data and size were developed to predict Magness-Taylor force. Use of sonic vibrational characteristics is proposed as a rapid nondestructive method for firmness sorting of apples.

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K.H.S. Peiris, G.G. Dull, R.G. Leffler, and S.J. Kays

A nondestructive method for measuring the soluble solids (SS) content of peaches [Prunus persica (L.) Batsch] was developed using near-infrared (NIR) spectrometry. NIR transmittance in the 800 to 1050 nm region was measured for four cultivars of peaches (`Blake', `Encore', `Red Haven', and `Winblo'), over a period of three seasons (1993 through 1995). Each fruit was scanned on both halves keeping the suture away from the incident light beam. Soluble solids contents of flesh samples taken from corresponding scanned areas were determined using a refractometer. Multiple linear regression models using two wavelengths were developed with second derivative spectral data and laboratory measurements of SS content. Multiple correlation coefficients (R) for individual cultivar calibrations within a single season ranged from 0.76 to 0.98 with standard error of calibration (SEC) values from 0.35% to 1.22%. Selected spectra and corresponding SS data in individual cultivar calibration data sets were combined to create season and cultivar calibration data sets to cover the entire range of SS contents within the season or within the cultivar. These combined calibrations resulted in R values of 0.92 to 0.97 with SEC values ranging from 0.37% to 0.79%. Simple correlations of validations (r) ranged from 0.20 to 0.94 and the standard error of prediction (SEP) ranged from 0.49% to 1.63% while the bias varied from -0.01% to -2.62%. Lower r values and higher SEP and bias values resulted when individual cultivar calibrations were used to predict SS levels in other cultivar validation data sets. Cultivar calibrations, season calibrations and the overall calibration predicted SS content of all validation data sets with a smaller bias and SEP and with higher r values. These results indicate that NIR spectrometry is suitable for rapid nondestructive determination of SS in peaches. Feasible applications of the method include packinghouse sorting of peaches for sweetness and parent and progeny fruit quality assessment in peach breeding programs. Using this technique fruit may be sorted into two or three sweetness classes. The technique may also potentially be extended to other fruit.

Free access

Masahiko Fumuro and Naoki Sakurai

cannot be reused in subsequent measurements. A nondestructive method for estimating flesh firmness would allow the same fruit to be measured in succession, and the effect of treatment could be detected in real time. Such an approach would also improve

Free access

Julia L. Whitworth, Andy Mauromoustakos, and Michael W. Smith

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F.J. Montero, J.A. de Juan, A. Cuesta, and A. Brasa

The importance of rapid, nondestructive, and accurate measurements of leaf area (LA) in agronomic and physiological studies is well known, but a search of the literature revealed little information available for grape (Vitis vinifera L.). The results described herein include a comparison of 12 different mathematical models for estimating leaf area in `Cencibel'. The simplest, most accurate regression equations were: LAi = 0.587 LW (R 2 = 0.987) and LAi = 0.588 LW (R 2 = 0.994), where LAi is leaf area measured using image analysis and LW is leaf length × maximum width. Use of maximum width (W), leaf length (L), petiole length (Lp), and dry weight of leaves (DML) as single variables in the regression equations were not as closely associated with total leaf area, although their R 2 values were also highly significant.

Free access

Robert E. Rouse, Sandra P. Perez, and Sally B. Davenport

The Minolta chlorophyll meter SPAD-502 (Minolta Camera Company, 101 Williams Drive, NJ 07446, USA) was evaluated as an accurate, nondestructive means to measure chlorophyll content in citrus leaves. Meter readings from leaves of sweet orange and grapefruit citrus cultivars were used to develop a standard curve for citrus. A significant correlation value of 0.96 was calculated between the chlorophyll meter readings and actual chlorophyll extraction levels. The development of a standard curve using the SPAD-502 chlorophyll meter had not been established on citrus. The SPAD-502 chlorophyll meter proved to be a quick, accurate, simple, and nondestructive way to determine chlorophyll content in citrus leaves.