Seleção recorrente no melhoramento do feijão carioca: estratégias para estimativa do progresso genético e para seleção de linhagens
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Universidade Federal de Viçosa
Abstract
A busca por novas cultivares é rotina nos programas de melhoramento de feijão carioca, devido a sua importância no mercado nacional. Os objetivos destes trabalhos foram comparar diferentes estratégias de avaliação do progresso genético (PG) no programa de seleção recorrente (SR) do feijoeiro e identificar linhagens elites com potencial para composição dos futuros ensaios de VCU em Minas Gerais. Para isso, foram utilizados dados do programa de SR de feijão carioca que vem sendo conduzido na Universidade Federal de Viçosa desde 2012. A população base (C 0 ) foi obtida pela combinação de 20 genitores de grãos tipo carioca, portadores de fenótipos favoráveis para os caracteres produtividade de grãos (PROD), arquitetura de plantas (ARQ) e aspecto comercial de grãos (AG). Os experimentos foram conduzidos na Estação Experimental da UFV, em Coimbra-MG. No capítulo 1, estimou-se o PG de um ciclo de SR por meio de diferentes estratégias: avaliação de famílias em cada ciclo utilizando experimentos com testemunhas comuns, avaliação simultânea das melhores famílias de cada ciclo e avaliação simultânea das melhores linhagens de cada ciclo. No capítulo 2, foram utilizados os índices distância genótipo-ideótipo e multiplicativo visando a seleção de linhagens. A interação linhagens x ambientes foi não significativa para PROD e ARQ, o que mostra consistência no comportamento das linhagens frente aos diferentes ambientes de avaliação. A linhagem no100 foi selecionada em primeiro lugar pelos dois índices utilizados e observou-se que oito linhagens se destacaram. Assim, foi possível concluir que o ganho genético para PROD em programas de SR no feijoeiro varia de acordo com a estratégia utilizada para estimar o PG, sugerindo que em estudos de estimativas de ganho genético isto deve ser levado em consideração. E os índices distância genótipo-ideótipo e multiplicativo se mostraram eficientes na seleção de linhagens que reúnam fenótipos de interesse de forma mais equilibrada. Palavras-chave: Ganho genético. Correlação. Índices de seleção
The search for new cultivars is routine in carioca bean breeding programs, due to their importance in the national market. In view of the above, the objectives of this study were to compare different strategies for evaluating genetic progress (GP) in the recurrent selection (RS) program for common beans and to identify elite strains with the potential for composing future VCU trials in Minas Gerais. For this, data from the Rio de Janeiro bean SR program that has been conducted at the Federal University of Viçosa since 2012 were used. The base population (C 0 ) was obtained by the combination of 20 carioca type grain parents, with favorable phenotypes for the characters grain yield, plant architecture and commercial grain aspect. The experiments were carried out at the UFV Experimental Station, in Coimbra-MG. In chapter 1, it was possible to estimate the PG of an SR cycle through different strategies: evaluation of families in each cycle using experiments with common witnesses, simultaneous evaluation of the best families in each cycle and simultaneous evaluation of the best lines of each cycle. In chapter 2, the genotype-ideotype and multiplicative distance indices were used, enabling balanced gains for all traits, which makes the selection of strains more efficient. Genotypic variability of treatments was observed for the three characters in the three GP evaluation strategies considered. The interaction between lines and environments was not significant for grain yield and plant architecture, which shows the stability and consistency of the lines in relation to the different environments evaluated. Strain no100 was selected first by the two indices used and it was observed that eight strains stood out. Thus, it was possible to conclude that the genetic gain for grain yield in RS programs in common beans varies according to the strategy used to estimate the GP, suggesting that in studies of genetic gain estimates this must be taken into account. Keywords: Genetic gain. Correlation. Selection index
The search for new cultivars is routine in carioca bean breeding programs, due to their importance in the national market. In view of the above, the objectives of this study were to compare different strategies for evaluating genetic progress (GP) in the recurrent selection (RS) program for common beans and to identify elite strains with the potential for composing future VCU trials in Minas Gerais. For this, data from the Rio de Janeiro bean SR program that has been conducted at the Federal University of Viçosa since 2012 were used. The base population (C 0 ) was obtained by the combination of 20 carioca type grain parents, with favorable phenotypes for the characters grain yield, plant architecture and commercial grain aspect. The experiments were carried out at the UFV Experimental Station, in Coimbra-MG. In chapter 1, it was possible to estimate the PG of an SR cycle through different strategies: evaluation of families in each cycle using experiments with common witnesses, simultaneous evaluation of the best families in each cycle and simultaneous evaluation of the best lines of each cycle. In chapter 2, the genotype-ideotype and multiplicative distance indices were used, enabling balanced gains for all traits, which makes the selection of strains more efficient. Genotypic variability of treatments was observed for the three characters in the three GP evaluation strategies considered. The interaction between lines and environments was not significant for grain yield and plant architecture, which shows the stability and consistency of the lines in relation to the different environments evaluated. Strain no100 was selected first by the two indices used and it was observed that eight strains stood out. Thus, it was possible to conclude that the genetic gain for grain yield in RS programs in common beans varies according to the strategy used to estimate the GP, suggesting that in studies of genetic gain estimates this must be taken into account. Keywords: Genetic gain. Correlation. Selection index
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SILVA, Fabíola dos Santos. Seleção recorrente no melhoramento do feijão carioca: estratégias para estimativa do progresso genético e para seleção de linhagens. 2021. 74 f. Tese (Doutorado em Fitotecnia) - Universidade Federal de Viçosa, Viçosa. 2021.