<b>Determining a model to estimate leaf area in Pornunça (<i>Manihot</i> sp.) using morphometric measures

Abstract

ABSTRACT. Pornunça is a species of the genus Manihot that has been cultivated as an option for animal feeding in the Brazilian semi-arid. Leaf area (LA) is important to determine forage plant growth, whose evaluation model has to meet the following characteristics: practicality, precision and low cost. The objective of this study was to set a model to determine the leaf area in Pornunça (Manihot sp.) from morphometric measurements of the leaf. The experimental design was in randomized blocks with three methods for determination of leaf area, and three blocks, with 144 replicates (leaves). For the determination of LA, the direct method (FAReal), treadmill leaf area meter (Li-Color 3100 © ) and linear dimensions were used. Data were subjected to regression analysis. There was a relationship between the actual leaf area (FAReal) for small, medium, large and total leaves, and the leaf area determined by the treadmill leaf area meter (FALi-Cor © ) with a high coefficient of determination for linear fit. The Pornunça leaf area obtained by the Li-Cor3100 © meter is approximately 10% lower compared to the FAReal method. The model that best fit the Ponunça leaf area estimation was the potential.Keywords: growth, plant, morphology, semiarid.Determinação de modelo para estimar área foliar da Pornunça (Manihot sp.), utilizando medidas morfométricas RESUMO. A Pornunça é uma espécie do gênero Manihot que está sendo cultivada como opção para alimentação animal no semiárido do Brasil. A área foliar (AF) é importante para determinar o crescimento de planta forrageira, e a avaliação tem que reunir as seguintes características: praticidade, precisão e baixo custo. O estudo objetivou estabelecer um modelo para determinar a área foliar da Pornunça (Manihot sp.) a partir de medidas morfométricas da folha. O delineamento experimental foi realizado em blocos ao acaso, com três tratamentos (métodos de determinação de área foliar) e três blocos, com o total de 144 repetições (folhas). Para determinação da AF, utilizou-se o método direto (AFReal), medidor de área foliar tipo esteira (Li-Cor 3100 © ) por meio das dimensões lineares. Os dados foram submetidos à análise de regressão. Houve uma relação entre a área foliar real (AFReal) para folhas pequenas, médias, grandes e total, e a área foliar determinada pelo medidor de área foliar tipo esteira (AFLi-Cor © ) apresentou coeficiente de determinação elevado para o ajuste linear. A área foliar da Pornunça obtida pelo medidor Li-Cor3100 © é de aproximadamente 10%, inferior, em comparação ao método AFReal. O modelo que melhor se ajustou para a estimativa da área foliar da Pornunça foi o potencial.

Comparison of methods for estimating leaf area in pornunça (Manihot sp.)

“…Leite et al (2019) evaluated the relationship between RLA and LW of millet genotype IPA BULK 1BF and concluded that the linear, gamma, and power models exhibited a power of explanation of 99.25%, 96.07%, and 99.96%, respectively. The results of this study were more accurate than those reported by Silva et al (2017) when estimating the leaf area of euphorbiaceous forage species. Guimarães et al (2019) found that for the evaluation of 17 cassava genotypes, the linear model had the best adjustment when the product between the length and width of the central lobe was used.…”

“…Performance indices of regression models considering as an explanatory variable the product of the length by width (LW) and the number of lobes (NL) to explain the real leaf area (RLA) and the digital leaf area (DLA) regression model, highlighting the high positive correlation observed between the models and the estimated variables. Silva et al (2017) observed that the number of lobes associated with the product of the length by the leaf width significantly increased the accuracy of the model of estimation of the real leaf area of pornunça.…”

“…Pornunça (Manihot sp.) is a member of the Euphorbiaceae family and descendant of the cassava (M. esculenta) and maniçoba (M. pseudoglaziovii) (Silva et al, 2017), which stands out for its high leaf production, elevated tolerance to waterthermal stress, high accumulation of starch, and high protein content (Alencar et al, 2015).…”

“…Linear measurements of leaves are commonly used in regression models as a fast, practical, and low-cost method to evaluate leaf area (Toebe et al, 2012). Leaf measurements have been used successfully to determine the leaf area in many crops, including sunflower (Aquino et al, 2011), passion fruit (Morgado et al, 2013), pineapple (Francisco et al, 2014), mango (Lima et al, 2012), gray mucuna (Cargnelutti Filho et al, 2012), millet (Leite et al, 2019), cassava (Zanetti et al, 2017), and pornunça (Silva et al, 2017).…”

ÁREA DE CLADÓDIO DA PALMA Opuntia Stricta UTILIZANDO DIMENSÕES LINEARES

“…Nota-se que existe correlação positiva entre ARC e CL com coeficiente de correlação r=0,90, o mesmo é observado entre ARC e AE r=0,93. Leite et al (2017) com Urochloa mosambicensis, Silva et al (2017) em Manihot sp.…”