No abstract

Plant growth analyses are important because they generate information on the demand and necessary care for each development stage of a plant. Nonlinear regression models are appropriate for the description of curves of growth, since they include parameters with practical biological interpretation. However, these models present information in terms of the conditional mean, and they are subject to problems in the adjustment caused by possible outliers or asymmetry in the distribution of the data. Quantile regression can solve these problems, and it allows the estimation of different quantiles, generating more complete and robust results. The objective of this research was to adjust a nonlinear quantile regression model for the study of dry matter accumulation in garlic plants (Allium sativum L.) over time, estimating parameters at three different quantiles and classifying each garlic accession according to its growth rate and asymptotic weight. The nonlinear regression model fitted was a Logistic model, and 30 garlic accessions were evaluated. These 30 accessions were divided based on the model with the closest quantile estimates; 12 accessions were classified as of lesser interest for planting, 6 were classified as intermediate, and 12 were classified as of greater interest for planting.

-The objective of this work was to identify nonlinear regression models that best describe dry matter accumulation curves over time, in garlic (Allium sativum) accessions, using Bayesian and frequentist approaches. Multivariate cluster analyses were made to group similar accessions according to the estimates of the parameters with biological interpretation (β 1 and β 3 ). In order to verify if the obtained groups were equal, statistical tests were applied to assess the parameter equality of the representative curves of each group. Thirty garlic accessions were used, which are kept by the vegetable germplasm bank of Universidade Federal de Viçosa, Brazil. The logistic model was the one that fit best to data in both approaches. Parameter estimates of this model were subjected to the cluster analysis using Ward's algorithm, and the generalized Mahalanobis distance was used as a measure of dissimilarity. The optimal number of groups, according to the Mojena method, was three and four, for the frequentist and Bayesian approaches, respectively. Hypothesis tests for the parameter equality from estimated curves, for each identified group, indicated that both approaches highlight the differences between the accessions identified in the cluster analysis. Therefore, both approaches are recommended for this kind of study.

No abstract

O Mercado de pimentas ornamentais está crescendo nos últimos anos, nacionalmente e internacionalmente, e tem estimulado o desenvolvimento de programas de melhoramento visando novas variedades de pimenta com caracteres desejáveis para o mercado ornamental. O uso da análise fatorial é uma técnica multivariada que permite reduzir um conjunto de variáveis em um número reduzido de fatores latentes, o que facilita o estudo de um conjunto de dados.  O objetivo do presente trabalho foi avaliar o potencial ornamental de genótipos de pimenta com base em análise fatorial. Foram avaliados 29 genótipos de Capsicum annnuum, com base em 12 características quantitativas, em delineamento inteiramente casualizado, com 5 repetições. As 12 características avaliadas foram resumidas em 3 fatores: qualidade de fruto (8 variáveis), porte da planta (2 variáveis) e arquitetura de planta (2 variáveis). Dentro de cada fator então as variáveis que são altamente correlacionadas. Os valores dos fatores foram preditos através dos escores. Por meio destes foram confeccionados gráficos para verificar o comportamento dos genótipos de C. annuum em relação aos fatores obtidos. 12 genótipos foram selecionados como os de maior potencial para ornamentação, podendo ser utilizados em futuros cruzamentos.

The present work had as main objective to use factor analysis to describe the structure of variability of characteristics considered commercially important in ornamental pepper, aiming to summarize the information contained in such variables in a smaller number of latent variables or factors. For that, 12 quantitative traits were evaluated in 29 pepper genotypes (Capsicum annuum). Of the factors created, 3 presented practical interpretation, grouping a total of 12 variables into factors related to “fruit quality” (8 variables), “plant size” (2 variables) and “plant architecture” (2 variables).

Peppers of the Capsicum annuum species are the most suitable for use in ornamentation, for having characters that confer aesthetic value, for being easy to cultivate and for good adaptability in pot. Despite the great variability that exists, in Brazil few commercial varieties are used for this purpose. It is of interest to the plant breeder, an ideotype that contains all the characteristics of interest for commercialization. The aim of the present study is to evaluate and select C. annuum genotypes, with potential for ornamentation that most closely resemble the proposed ideotype. 14 quantitative traits and seven qualitative traits were evaluated in 29 C. annuum genotypes, in a completely randomized design with five replications. The cultivar Calypso was used as an ideotype for presenting desirable characters to the ornamental pepper market. Nine genotypes were selected as the most similar to the Calypso ideotype (ideotype), with the potential to be used in future crossings between them and / or with the ideotype.

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