Predição de ganhos genéticos e diversidade genética em genótipos de batata-doce obtidos por meio de polycross
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Data
2022
Autores
Mariano, Giovana Guerra
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Universidade Estadual Paulista (Unesp)
Resumo
A cultura da batata-doce apresenta grande variabilidade genética, mas é necessário estimar parâmetros genéticos das populações sob melhoramento, principalmente quando se pretende praticar seleção com base em vários caracteres, da mesma forma é importante quantificar a diversidade genética para recomendar intercruzamentos para continuidade do programa. Assim, objetivou-se estimar parâmetros genéticos, selecionar clones por meio de índice de seleção e avaliar a divergência genética em uma população de batata-doce obtida a partir de cruzamentos não controlados. O experimento foi conduzido no município de Ilha Solteira, no período de junho a novembro de 2020. Foram avaliados 144 clones e três testemunhas, totalizando 147 tratamentos. Utilizou-se delineamento em blocos casualizados com duas repetições de três plantas por parcela. A análises dos dados foi realizada por modelos mistos (REML/BLUP) e foi aplicado o índice proposto por Mulamba & Mock adotando pressão de seleção de 17,3% para a seleção dos clones superiores. A divergência genética foi estudada por meio de análise multivariada, sendo os dados agrupados pelo método de otimização proposto por Tocher e o método hierárquico de Ward, com os 25 clones selecionados que possuíam melhores resultados nos caracteres de interesse. A seleção direta possibilitou maior predição de ganho para cada caráter, porém avaliando conjuntamente houve a maximização de ganhos seletivos em todos os caracteres de interesse. Entre os selecionados, os clones 38, 63, 79, 77 e 5 foram os mais indicados para as próximas etapas de melhoramento da batata-doce com características para produção e consumo de mesa. Entre os clones considerados mais promissores para futuras hibridações, recomenda-se os cruzamentos entre os clones 63 x 4; 5 x 4; 38 x 53; 79 x 53; 77 x 25.
The sweet potato crop presents great genetic variability, but it is necessary to estimate genetic parameters of the populations under breeding, mainly when it is intended to practice selection based on several characters, in the same way it is importante to quantify the genetic diversity to recommend intercrosses for the continuity of the program. Thus, the objective was to estimate genetic parameters, select clones by means of a selection index and evaluate the genetic divergence in a sweet potato population obtained from uncontrolled crossings. The experiment was conducted in the municipality of Ilha Solteira, from june to november 2020. A total of 144 clones and three controls were evaluated, totaling 147 treatments. A randomized block design with two replications of three plants per plot was used. Data analysis was performed by mixed models (REML/BLUP) and the index proposed by Mulamba & Mock was applied, adopting a selection pressure of 17.3% for the selection of superior clones. Genetic divergence was studied by means of multivariate analysis, with data were grouped by the optimization method proposed by Tocher and the hierarchical method of Ward, with the 25 selected clones that had the best results in the characters of interest. The direct selection allowed a greater prediction of gain for each character, however, evaluating together, there was a maximization of selective gains in all characters of interest. Among those selected, clones 38, 63, 79, 77 and 5 were the most suitable for the next stages of improvement of sweet potato with characteristics for production and table consumption. Among the clones considered most promising for future hybridizations, crossbreeding between 63 x 4 clones are recommended; 5 x 4; 38 x 53; 79 x 53; 77 x 25.
The sweet potato crop presents great genetic variability, but it is necessary to estimate genetic parameters of the populations under breeding, mainly when it is intended to practice selection based on several characters, in the same way it is importante to quantify the genetic diversity to recommend intercrosses for the continuity of the program. Thus, the objective was to estimate genetic parameters, select clones by means of a selection index and evaluate the genetic divergence in a sweet potato population obtained from uncontrolled crossings. The experiment was conducted in the municipality of Ilha Solteira, from june to november 2020. A total of 144 clones and three controls were evaluated, totaling 147 treatments. A randomized block design with two replications of three plants per plot was used. Data analysis was performed by mixed models (REML/BLUP) and the index proposed by Mulamba & Mock was applied, adopting a selection pressure of 17.3% for the selection of superior clones. Genetic divergence was studied by means of multivariate analysis, with data were grouped by the optimization method proposed by Tocher and the hierarchical method of Ward, with the 25 selected clones that had the best results in the characters of interest. The direct selection allowed a greater prediction of gain for each character, however, evaluating together, there was a maximization of selective gains in all characters of interest. Among those selected, clones 38, 63, 79, 77 and 5 were the most suitable for the next stages of improvement of sweet potato with characteristics for production and table consumption. Among the clones considered most promising for future hybridizations, crossbreeding between 63 x 4 clones are recommended; 5 x 4; 38 x 53; 79 x 53; 77 x 25.
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Palavras-chave
Ipomoea batatas (L.) Lam, Variabilidade genética, Índice de seleção, Ganho com seleção, Métodos de agrupamento, Genetic variability, Selection index, Selection gain, Clustering methods