A simple and non-destructive model for individual leaf area estimation in citrus

Abstract

-Introduction. Leaf area is often related to plant growth, development, physiology and yield. Many non-destructive models have been proposed for leaf area estimation of several plant genotypes, demonstrating that leaf length, leaf width and leaf area are closely correlated. Thus, the objective of our study was to develop a reliable model for leaf area estimation from linear measurements of leaf dimensions for citrus genotypes. Materials and methods. Leaves of citrus genotypes were harvested, and their dimensions (length, width and area) were measured. Values of leaf area were regressed against length, width, the square of length, the square of width and the product (length × width). The most accurate equations, either linear or secondorder polynomial, were regressed again with a new data set; then the most reliable equation was defined. Results and discussion. The first analysis showed that the variables length, width and the square of length gave better results in second-order polynomial equations, while the linear equations were more suitable and accurate when the width and the product (length × width) were used. When these equations were regressed with the new data set, the coefficient of determination (R 2 ) and the agreement index 'd' were higher for the one that used the variable product (length × width), while the Mean Absolute Percentage Error was lower. Conclusion. The product of the simple leaf dimensions (length × width) can provide a reliable and simple non-destructive model for leaf area estimation across citrus genotypes. Résumé -Introduction. La surface foliaire est souvent liée à la croissance, le développement, la physiologie et le rendement des plantes. Beaucoup de modèles non destructifs ont été proposés pour estimer la surface foliaire de plusieurs génotypes végétaux ; ils ont montré que la longueur et la largeur des feuilles, de même que la surface foliaire, étaient étroitement corrélées. L'objectif de notre étude a donc été de développer un modèle fiable pour estimer la surface foliaire à partir de mesures linéaires des dimensions de feuilles pour les génotypes d'agrumes. Matériel et méthodes. Les feuilles de certains génotypes d'agrumes ont été récoltées et leurs dimensions (longueur, largeur et surface) ont été mesurées. La surface foliaire a été corrélée à la longueur, la largeur, le carré de la longueur, le carré de la largeur et le produit (longueur × largeur). Les équations les plus précises, qu'elles soient linéaires ou polynomiales de second ordre, ont été testées à nouveau avec un nouvel ensemble de données, puis l'équation la plus fiable a été définie. Résultats et discussion. La première analyse a montré que les variables longueur, largeur et carré de la longueur donnaient de meilleurs résultats dans les équations polynomiales de second ordre, tandis que les équations linéaires étaient plus appropriées et précises lorsque la largeur et le produit (longueur × largeur) étaient utilisés. Lorsque ces équations ont été utilisées avec le nouvel ensemble de données, le coeffici...

Models for leaf area estimation in dwarf pigeon pea by leaf dimensions

“…Similar results were obtained by Antunes et al (2008), Tsialtas et al (2008), Mazzini et al (2010), and Padrón et al (2016), when studying respectively coffee, grapevine, citrus, and bell pepper with models presenting high R² by using the product of the leaves length times width. This can be explained due to shape differences in each leaflet, which may vary from more lanceolate to more oval.…”

Regression models for estimating leaf area of seedlings and adult individuals of Neotropical rainforest tree species

“…There are several published studies of nondestructive estimations of LA involving measurements of leaf dimensions as independent variables, but using different regression models, including power (Kandiannan et al, 2002;Antunes et al, 2008;Pompelli et al, 2012;Wang and Zhang, 2012;Misle et al, 2013) and second-order polynomial models (Mazzini et al, 2010). In our study, we adopted the use of linear regression models because they are simpler and provide good estimates for a great number of plant species with different leaf areas and leaf shapes when compared with non-linear regression models (Cristofori et al, 2007;Mazzini et al, 2010;Rouphael et al, 2010;Wang and Zhang, 2012;Souza and Habermann, 2014).…”

“…Our results demonstrate that it is not always possible to use models developed for adults in studies with seedlings, and vice-versa. This fact is very critical, since most of the models available in the literature have been developed based upon leaves of adult plants (Cristofori et al, 2007;Mazzini et al, 2010;Rouphael et al, 2010;Wang and Zhang, 2012;Souza and Habermann, 2014). The use of models developed with leaves of adults in studies with Table 4.…”

“…In our study, we adopted the use of linear regression models because they are simpler and provide good estimates for a great number of plant species with different leaf areas and leaf shapes when compared with non-linear regression models (Cristofori et al, 2007;Mazzini et al, 2010;Rouphael et al, 2010;Wang and Zhang, 2012;Souza and Habermann, 2014). In addition, we tested two geometric formulas for estimating LA from simple linear regression models.…”

Allometric models for leaf area estimation across different leaf-age groups of evergreen broadleaved trees in a subtropical forest

“…However, accurate LA measurement of a large number of leaves, especially in the field, is time-consuming, laborious, and usually destructive (Beerling and Fry 1990). Thus, nondestructive and easily applied models were widely developed for LA estimation based on simple measurements of L and/or W mainly for fruit trees (Ramkhelawan and Bratwaite 1990, Potdar and Pawar 1991, Williams and Martinson 2003, Demirsoy et al 2004, Cittadini and Peri 2006, Serdar and Demirsoy 2006, Mendoza-de Gyves et al 2007, Demirsoy 2009, Demirsoy and Lang 2010, Mazzini et al 2010 or crop species (Rouphael et al 2006, 2007, 2010a, 2010b, Salerno et al 2005, Peksen 2007, Antunes et al 2008, Tsialtas and Maslaris 2008, Fascella et al 2009, Kandiannan et al 2009, Kumar 2009, Zhou and Shoko 2009, Kumar and Sharma 2010, Olfati et al 2010. As an alternative for LA measurement, this indirect, nondestructive method can provide accurate LA estimates and help the in situ LA estimation, which is also necessary for the successive measurements on the same leaf (Beerling and Fry 1990).…”