Navegando por Autor "Amaral Júnior, Antonio Teixeira do"

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Biometria aplicada ao melhoramento intrapopulacional do maracujazeiro amarelo
(Revista Ciência Agronômica, 2012-07) Reis, Ronaldo Viana dos; Silva, Marcelo Geraldo de Morais; Viana, Alexandre Pio; Amaral Júnior, Antonio Teixeira do; Gonçalves, Leandro Simões Azeredo
Objetivou-se estimar parâmetros genéticos associados a onze características agronômicas de uma população de maracujazeiro amarelo sob seleção recorrente, utilizando-se 140 progênies de irmãos completos do segundo ciclo, com plantio em outubro de 2007, em delineamento látice quadrado simples e parcelas constituídas de três plantas. Os quadrados médios das características revelaram significância pelo teste F para o efeito de progênies, indicando que existe variabilidade genética a ser explorada nos próximos ciclos. As estimativas dos coeficientes de herdabilidade variaram de 19,54 a 71,38%. As médias das principais características de importância agronômica da população avaliadas foram superiores às das testemunhas, ratificando o potencial da população em gerar população superior com o acúmulo de alelos favoráveis nos sucessivos processos seletivos. As estimativas dos parâmetros genéticos e fenotípicos das principais características de importância econômica revelam a possibilidade de sucesso com a seleção de progênies superiores de maracujazeiro amarelo no intento de registro e proteção de nova cultivar.
Heterotic parametrization for economically important traits in popcorn
(Acta Scientiarum. Agronomy, 2009-07) Cruz, Cosme Damião; Vieira, Rafael Augusto; Souza Neto, Israel Leite; Bignotto, Lucas Souto; Amaral Júnior, Antonio Teixeira do; Scapim, Carlos Alberto
Six popcorn varieties were crossed in a diallel mating scheme to obtain 15 F1 hybrids, with the purpose of analyzing the estimates of heterotic parametrization for agronomically important traits. The genitors and hybrids were evaluated in randomized block design with three replications in Viçosa and Visconde do Rio Branco, in Minas Gerais State, Brazil, in three growing seasons. Six traits were evaluated, including grain yield and popping expansion. There were highly significant effects for treatments, varieties and mean heterosis for plant and ear heights, and for the others traits the significance extended to all sources of variation. Amarela and Viçosa revealed superiority for grain yield in relation to performance per se, while Rosa Claro expressed the highest effect of varietal heterosis. The best combinations for grain yield were Roxa x Viçosa, Amarela x Rosa Claro, Rosa Claro x Beija-Flor and Branca x Beija-Flor. For popping expansion, there were positive and negative values for specific heterosis in all growing seasons evaluated, ratifying the influence of bidirectional dominance on this trait. Simultaneous genetic gains for grain yield and popping expansion may be obtained by using Viçosa in intrapopulational programs, while Amarela and Rosa Claro are recommended for using in interpopulational breeding.
Pi statistics underlying the evaluation of stability, adaptability and relation between the genetic structure and homeostasis in popcorn
(Acta Scientiarum. Agronomy, 2010-04) Paula, Thiago Otávio Mendes de; Peternelli, Luiz Alexandre; Amaral Júnior, Antonio Teixeira do; Gonçalves, Leandro Simões Azeredo; Scapim, Carlos Alberto; Silva, Vanessa Quitete Ribeiro da
The purpose of this study was to evaluate the interaction between genotypes and environments, evaluate adaptability and stability, and study the relationship between genetic structure and homeostasis. In addition to landrace, the study evaluated recommended genotypes or genotypes in experimental recommendation stages (varieties and hybrids) in three environments in northern and northwestern Rio de Janeiro State. Eight traits were measured, including grain yield and popping expansion. The individual analysis of variance revealed significant differences for all traits at 1% probability. In the combined analysis of variance, the genotype by environment interaction was significant at 1% probability for all traits except ear height. The interaction was simple for all traits except mean number of ears. The method of Lin and Binns detected the most suitable and stable genotypes, and also the most productive. UNB2U-C4 and IAC112 contained the lowest values of general Pi. Of those, UNB2U-C4 contributed least to the interaction, and IAC112 ranked fourth in interaction. UNB2U-C4 stood out with the best adaptation to favorable and unfavorable environments. No association between the genetic structure and stability degree in popcorn was observed.