Estimativa da área foliar de meloeiro em estádios fenológicos por fotos digitais

Lopes, Sidinei José; Brum, Betânia; Santos, Valdecir José dos; Fagan, Evandro Binotto; Luz, Gean Lopes da; Medeiros, Sandro Luís Petter

doi:10.1590/s0103-84782007000400039

Cited by 15 publications

(27 citation statements)

References 3 publications

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“…In contrast to the results obtained by Tavares Júnior et al (2002) and Dombroski et al (2010), who compared the digital scanner method with the leaf disc method, we concluded that the LA was overestimated in the leaf disc method. Dombroski et al (2010), working with a pine cone culture, used a correction factor (0.894) to balance the overestimation of LA by the leaf disc method. In a study that used Chrysobalanus icaco, Cunha et al (2010) found a high coefficient of determination (R² = 0.978) and a high angular coefficient (0.994) between the digital scanner and the leaf disc methods.…”

Section: Resultscontrasting

confidence: 99%

“…In addition, this finding partially clarifies the differences between the present and past research results. The underestimation of LA in the present study is proportional to or smaller than the overestimation that was observed in other studies, such as those by Dombroski et al (2010), Marrocos et al (2010) and Lucena et al (2011).…”

Section: Resultscontrasting

confidence: 55%

“…In a comparison between the leaf disc method and the digital scanner analysis method in beet plants, Marrocos et al (2010) obtained a result of R² = 0.87. The authors suggest that this result occurred because the leaves were not always perforated in the same place, which increased the SLA variability and error and decreased the R² value.…”

Section: Resultsmentioning

confidence: 99%

“…However, this hypothesis is not supported by the similar CVs for the observed SLAs at each sampling date (Table 2). Lopes et al (2007) determined that the highest accuracy of digital photo LA estimations occurred during the phenological growth stages. In this study, the authors only used one cultivar and only sampled at one date of plant development.…”

Section: Resultsmentioning

confidence: 99%

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<b>Efficiency of the leaf disc method for estimating the leaf area index of soybean plants</b> - doi: 10.4025/actasciagron.v35i4.16290

Pierozan

Kawakami

2013

Acta Sci. Agron.

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ABSTRACT. The objective of this study was to evaluate the efficiency of the leaf disc method for estimating the leaf area index (LAI) of soybean plants in comparison with the digital photo method. A split-plot experimental design was used with three replications. The LAIs calculated by the leaf disc and digital photo methods were compared at four growth stages in four soybean cultivars (subplot). These soybean cultivars were sowed in Guarapuava, Paraná State, Brazil, at three different sowing dates (main plot) in the 2010/2011 growing season. Regression analysis was used for each group of samples, and the efficiency of the leaf disc method was evaluated on the basis of the coefficient of determination (R²), the calculated F and the intersection and abscissa errors. The regression analysis that compared the two methods resulted in highly significant F values and low errors for all sample groups, which showed the effectiveness of the leaf disc method. Although the R 2 value was high for all of the analyses, the values were minor for the separate growth stage analysis, especially for the samples collected at the V9 and R2 stages. The results indicated that the specific leaf area calculated by the leaf disc method was lesser to the specific leaf area calculated by the digital photo method. The leaf disc method is an efficient and robust method for estimating the LAI of soybean plants.Keywords: Glycine max, cultivars, digital photos, growth stages, sowing dates.Eficiência do método de discos foliares para estimar o índice de área foliar em plantas de soja RESUMO. O objetivo deste estudo foi avaliar a eficiência do método dos discos foliares para estimar o índice de área foliar (IAF) de plantas de soja em comparação como método de fotos digitais. O delineamento experimental utilizado foi o de parcelas subdivididas com três repetições. Os IAFs calculados pelo método dos discos e das fotos digitais foram comparados em quatro estádios de desenvolvimento, e em quatro cultivares de soja (subparcelas). As cultivares de soja foram semeadas em Guarapuava, Estado do Paraná, Brasil, em três diferentes datas de semeadura (parcelas principais) na safra de 2010/2011. Análise de regressão foi feita para cada grupo de amostras, e a eficiência do método dos discos foi avaliado com base no coeficiente de determinação (R²), no F calculado e nos erros da interseção e da abscissa. As análises de regressão que compararam os dois métodos resultaram em F altamente significativos e baixos erros para todos os grupos de análises, o que mostrou a eficácia do método dos discos. Embora o valor de R 2 tenha sido elevado em todas as análises, os valores foram menores para as análises separadas por estádios de crescimento, especialmente para as amostras coletadas nos estádios V9 e R2. Os resultados indicaram que a área foliar específica calculada pelo método dos discos foliares foi menor do que a área foliar específica calculada pelo método das fotos digitais. O método dos discos foliares é um eficiente e robusto método para estimar o IAF de plantas...

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Section: Resultscontrasting

confidence: 99%

Section: Resultscontrasting

confidence: 55%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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<b>Efficiency of the leaf disc method for estimating the leaf area index of soybean plants</b> - doi: 10.4025/actasciagron.v35i4.16290

Pierozan

Kawakami

2013

Acta Sci. Agron.

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“…There are nondestructive methods for LA determination using simple and easily operated devices that preserve leaf integrity (Adami et al, 2008;Fagundes et al, 2009;Bakhshandeh et al, 2011). Some examples are models generated for tomato and cucumber (Blanco & Folegatti, 2003), melon (Lopes et al, 2007), sunflower (Maldaner et al, 2009) and crambe (Toebe et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Non-destructive models for leaf area determination in canola

Tartaglia

Righi

Rocha

et al. 2016

Rev. bras. eng. agríc. ambient.

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A B S T R A C TThe leaf is a very important structure of the plants, since it allows gas exchanges and the transformation of light energy into chemical energy. This study aimed to generate and test mathematical models for leaf area estimation in canola based on leaf dimensions. Two experiments were conducted with canola in 2014, in which leaves were collected in different phenological stages with different sizes and shapes. Subsequently, leaf length, width and area were measured (with automatic meter) in 606 leaves, which included 371 ovate and 235 lanceolate leaves. The models were generated using length, width and length versus width as independent variables and leaf area as dependent variable. The models were validated using a group of leaves different from those used to generate the models. A total of 27 models were obtained and those with best statistics and higher simplicity were selected. The polynomial model LA = 0.88735 W 2 + 0.93503 W and the power model LA = 1.1282 W 1.9396 can be used for both types of leaves and have high accuracy in the estimation of canola leaf area.Modelos não destrutivos para determinação da área foliar em canola R E S U M O A folha é uma estrutura de grande importância para as plantas, visto que por meio dela ocorrem as trocas gasosas e a transformação da energia luminosa em energia química. O objetivo neste trabalho foi gerar e testar modelos matemáticos para a estimativa de área foliar de folhas de canola em função das dimensões foliares. Para isto foram realizados dois experimentos com canola no ano de 2014 e coletadas folhas em diferentes estágios fenológicos e de diferentes tamanhos e formas; posteriormente foram medidos o comprimento, a largura e a área foliar (com medidor automático) de 606 folhas dentre as quais 371 ovaladas e 235 lanceoladas. Os modelos foram gerados utilizando-se comprimento, largura e comprimento versus largura como variáveis independentes e a área foliar como variável dependente. Os modelos foram validados com um grupo distinto de folhas dos utilizados para a geração. Obteve-se o total de 27 modelos escolhendo-se aqueles que apresentaram as melhores estatísticas e maior simplicidade. Os modelos que podem ser utilizados para ambos os tipos de folhas e apresentam alta precisão de estimativa de área foliar em canola, são o modelo polinomial AF = 0,88735 L 2 + 0,93503 L e o modelo potencial AF = 1,1282 L 1,9396 . Key words:Brassica napus ovate leaves lanceolate leaves modeling Palavras-chave:Brassica napus folhas ovaladas folhas lanceoladas modelagem

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Leaf area estimation in muskmelon by allometry

Misle¹,

Kahlaoui²,

Hachicha³

et al. 2013

Photosynt.

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This study developed a method for estimating the leaf area (LA) of muskmelon by using allometry. The best linear measure was evaluated first, testing both a leaf length and width (W). Leaf samples were collected from plants grown in containers of different sizes, leaves of four cultivars, at different develpoment stages, and of different leaf sizes. Two constants of a power equation were determined for relating allometrically a linear leaf measure and LA, in a greenhouse crop. W proved to be a better fit than the leaf length. The maximum attainable W and LA were estimated at W x = 15.4 cm and LA x = 174.1 cm 2 . The indicators of fit quality showed that the function was properly related to LA and W as: LA/LA x = A o × (W/W Lx ) b ; the allometric exponent was b = 1.89, where R 2 = 0.9809 (n = 484), the absolute sum of squares, 0.4584, and the standard deviation of residues, 0.03084, based on relative values calculations (LA/LA x and W/W Lx ). The relationship was not affected by the cultivar, crop age, leaf size or stress treatment in the seedling stage. The empirical value of allometric constant (A 0 ) was estimated as 0.963.

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Estimativa da área foliar de meloeiro em estádios fenológicos por fotos digitais

Abstract: RESUMO O objetivo deste trabalho foi avaliar a precisão do método de fotos digitais na estimativa da área foliar de meloeiro e encontrar modelos matemáticos de estimativa da área foliar

Cited by 15 publications

References 3 publications

<b>Efficiency of the leaf disc method for estimating the leaf area index of soybean plants</b> - doi: 10.4025/actasciagron.v35i4.16290

<b>Efficiency of the leaf disc method for estimating the leaf area index of soybean plants</b> - doi: 10.4025/actasciagron.v35i4.16290

Non-destructive models for leaf area determination in canola

Leaf area estimation in muskmelon by allometry

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