Grouping sunflower genotypes for yield, oil content, and reaction to Alternaria leaf spot using GGE biplot

Abstract

-The objective of this work was to evaluate the suitability of the multivariate method of principal component analysis (PCA) using the GGE biplot software for grouping sunflower genotypes for their reaction to Alternaria leaf spot disease (Alternariaster helianthi), and for their yield and oil content. Sixty-nine genotypes were evaluated for disease severity in the field, at the R3 growth stage, in seven growing seasons, in Londrina, in the state of Paraná, Brazil, using a diagrammatic scale developed for this disease. Yield and oil content were also evaluated. Data were standardized using the software Statistica, and GGE biplot was used for PCA and graphical display of data. The first two principal components explained 77.9% of the total variation. According to the polygonal biplot using the first two principal components and three response variables, the genotypes were divided into seven sectors. Genotypes located on sectors 1 and 2 showed high yield and high oil content, respectively, and those located on sector 7 showed tolerance to the disease and high yield, despite the high disease severity. The principal component analysis using GGE biplot is an efficient method for grouping sunflower genotypes based on the studied variables.Index terms: Alternariaster helianthi, Helianthus annuus, disease resistance, principal component analysis. Agrupamento de genótipos de girassol quanto à produtividade, ao teor de óleo e à reação à mancha de alternária por GGE biplotResumo -O objetivo deste trabalho foi avaliar a adequação do uso do método multivariado de análise de componentes principais (ACP), com uso do programa GGE biplot, para o agrupamento de genótipos de girassol quanto à sua reação à mancha de alternária (Alternariaster helianthi), e quanto à produtividade e ao teor de óleo. Sessenta e nove genótipos foram avaliados quanto à severidade da doença em campo, na fase de desenvolvimento R3, em sete safras, em Londrina, PR, com uso de uma escala diagramática própria, desenvolvida para esta doença. A produtividade e o teor de óleo também foram avaliados. Os dados foram padronizados com o programa Statistica, e o GGE biplot foi utilizado para ACP e exibição gráfica dos dados. Os dois primeiros componentes principais explicaram 77,9% da variação total. De acordo com o biplot poligonal, obtido com os dois primeiros componentes principais e as três variáveis resposta, os genótipos foram divididos em sete setores. Os genótipos alocados nos setores 1 e 2 apresentaram alta produtividade e alto teor de óleo, respectivamente, e os agrupados no setor 7 apresentaram tolerância à doença e alta produtividade, apesar de elevada severidade da doença. O método de análise de componentes principais com uso do GGE biplot é eficiente para agrupar genótipos de girassol com base nas variáveis estudadas.Termos para indexação: Alternariaster helianthi, Helianthus annuus, resistência a doenças, análise de componentes principais.

Yield potential of different sunflower genetic classes: A multivariate approach

“…According to Rencher (2002), at least 70% of the total variation must be explained by the first two principal components; therefore, PC1 and PC2 may be used to study this data set. Such result is in compliance with that by Leite and Oliveira (2015) and Mousavi et al (2016) who found that the first two CPs explain more than 70% of the original variation.…”

“…Examples listed in the studies by Brankovic et al (2012), Leite and Oliveira (2015) and Oliveira et al (2018) corroborate the technique adequacy to simultaneously assess different sunflower-crop characteristics.…”

“…The biplot graphic representation is a key element to reveal the relation between variables, between observations, and between variables and observations. Many studies have evidenced that this method completes the data in a practical manner and allows better identifying the genotypes (Leite and Oliveira, 2015).…”

Main aspects of sunflower production in Brazil

“…Thus, effective control is based on an integrated program, which includes zoning for climatic risk, use of genetic resistance to diseases and adequate cultural practices. A great deal of work has been done in the search for genetic resistance to diseases, especially for Alternaria leaf spot, Sclerotinia head rot and downy mildew (Leite et al, 2007b;Leite and Oliveira, 2015). However, so far no commercial hybrids or varieties have a level of resistance to Sclerotinia suitable for cultivation under favorable conditions to disease (Leite, 2014).…”

Severity of Septoria Leaf Spot and Sunflower Yield Due to Leaf Wetness Duration

“…Low yield is frequently observed due to different adverse factors, which prevent the yield potential expression of the available genotypes. In Brazil, part of this problem emerges from the difficulty in carrying out disease control (Gomes et al, 2008;Leite & Oliveira, 2015).…”