Número mínimo de medições para a avaliação acurada de características agronômicas de pinhão-manso

Abstract

Resumo -O objetivo deste trabalho foi identificar o método mais eficaz para estimar coeficientes de repetibilidade em progênies de meios-irmãos de pinhão-manso (Jatropha curcas) e predizer o número mínimo de medições necessárias para algumas características agronômicas da oleaginosa. Avaliaram-se 18 famílias de meios-irmãos, em delineamento de blocos ao acaso, com três repetições, de 2009 a 2013. Nesse período, as seguintes características foram avaliadas: altura de plantas, diâmetro do caule, número de ramos por planta, projeção da copa na linha, projeção da copa na entrelinha e produtividade de grãos. O coeficiente de repetibilidade (r) foi estimado a partir de diferentes estratégias: análise de variância; análise dos componentes principais (ACP), com base na matriz de correlações (CPCOR); ACP, com base na matriz de variâncias e covariâncias fenotípicas (CPCOV); e análise estrutural, com base na matriz de correlações. A estratégia CPCOV proporciona estimativas mais acuradas do coeficiente de repetibilidade e do número de medições necessárias (no mínimo quatro) para avaliação acurada (mínimo 80%) das características, devido ao comportamento cíclico das progênies.Termos para indexação: Jatropha curcas, análise multivariada, eficiência de seleção, precisão experimental, repetibilidade. Minimum number of measurements for the accurate evaluation of agronomic traits in physic nutAbstract -The objective of this work was to identify the most effective method to estimate the coefficient of repeatability in progenies of half-sib families of physic nut (Jatropha curcas), and to predict the minimum number of measurements required for some agronomic traits of this oilseed crop. Eighteen half-sib families, in a randomized complete block design with three replicates, were evaluated from 2009 to 2013. In this period, the following traits were evaluated: plant height, stem diameter, number of branches per plant, crown projection on the line, crown projection on the space between rows, and grain yield. The repeatability coefficient (r) was estimated considering different strategies: analysis of variance; principal component analysis (PCA) based on the correlation matrix (PCCOR); PCA based on the matrix of phenotypic variance and covariance (PCCOV); and structural analysis based on the correlation matrix. The PCCOV strategy provides the most accurate estimates of the repeatability coefficient and of the number of measurements (minimum of four), which are required for an accurate evaluation (minimum 80% accuracy) of the traits, due to the cyclical behavior of the progenies.

Research Article Minimum number of measurements for evaluating Bertholletia excelsa.

“…The F-test also revealed a significant effect for measurements, which indicates that there has been a change in the mean of the genotypes over the years. These results are similar to those obtained for other perennial crops (Lopes et al, 2001;Degenhardt et al, 2002;Danner et al, 2010;Bruna et al, 2012;Negreiros et al, 2014;Lessa et al, 2014;Teodoro et al, 2016) and reinforce the need to study the minimum number of measurements to select superior Brazil nut genotypes for a productive increase. The Scott-Knott test clustered the 75 Brazil nut genotypes in three homogeneous groups for the number of fruits and two for the dry mass of seeds ( Table 2).…”

“…The dimensioning of the number of measurements has been conducted for several perennial crops such as acerola (Lopes et al, 2001), guava (Degenhardt et al, 2002), araçazeiro and pitangueira (Danner et al, 2010), peach (Bruna et al, 2012), sweet orange (Negreiros et al, 2014), banana , and Jatropha (Teodoro et al, 2016). The repeatability coefficient in the Brazil nut was estimated by Pedrozo et al (2015) and Assis (2016) from the methodology of mixed models.…”

Multivariate diallel analysis allows multiple gains in segregating populations for agronomic traits in Jatropha

“…Thus, to install a genetic breeding program of Jatropha in Brazil numerous studies have been conducted in recent years, such as studies on genetic diversity (Rosado et al, 2010;Bhering et al, 2015), estimates of genetic parameters Teodoro et al, 2016d) and gains with selection Peixoto et al, 2016), repeatibility , Teodoro et al, 2016b, and path analysis (Teodoro et al, 2016c). However, for the formation of base populations for practicing the selection, diallel is the main genetic design used (Cruz et al, 2012).…”

Repeatability of biometric and fruit and seed yield traits of sacha inchi

“…In an assessment of 18 half-sib progenies of jatropha (Jatropha curcas), a species of Euphorbiaceae that is also oleaginous, Teodoro et al (2016) proposed that four measurements would be required to ensure an accurate evaluation (minimum 80%) of the analyzed traits, including productivity. These authors also indicated PCcov as the most accurate method to estimate the repeatability coefficient.…”