No abstract

A cultura da soja é extremamente importante para a economia brasileira, por isso formas para aumentar o rendimento de grãos devem ser consideradas. Uma proposta para aumentar produtividade pode ser a aplicação de micronutriente via foliar. O objetivo do trabalho foi avaliar a resposta da cultura da soja sob diferentes concentrações de boro (B), aplicadas via pulverização foliar, em diferentes estádios de desenvolvimento sob sistema de plantio direto. O delineamento experimental utilizado foi blocos ao acaso com parcelas subdivididas. Os tratamentos constituíram de quatro doses de B (0, 150, 300 e 450 g ha-1) aplicadas no estádio vegetativo (V6) e no reprodutivo (R2). Foi avaliado o número de legumes por planta, número de grãos por legumes, massa de mil grãos e a produtividade em kg ha-1. Os dados foram submetidos à análise de variância e comparados pelo teste Tukey a 5% de significância e análise de regressão. A adubação foliar com B promoveu aumento na massa média de grãos quando aplicado em R2 e no número de grãos por legumes (2,43 grãos para dose ajustada de 320 g ha-1 de B). No entanto, a produtividade (3200 kg ha-1) não apresentou comportamento diferenciado independentemente da dose e do estádio fenológico de aplicação.   Palavras-chave: Glycine max (L), Absorção de nutrientes, Micronutriente.

The objective of this work was to estimate the phenotypic correlation and the direct and indirect effects of the aerial part components of common bean (Phaseolus vulgaris) that are associated with root distribution, in order to facilitate the indirect selection for this character. Sixteen genotypes were used, from which 12 are segregating populations in the F6 generation and four are fixed populations, which were conducted in field conditions in a randomized complete block design, with two replicates. The root system evaluation was performed according to Böhm’s method. Pearson’s phenotypic correlation was estimated by the path analysis. The characters stem diameter, leaf area index, first pod set, and root angle showed the highest positive correlations with root distribution and, therefore, may help the indirect selection for this character. The residual effect was higher than the determination coefficient, which indicates that the independent characteristics do not have a total influence on root distribution, and the low values of the determination coefficients can be attributed to environmental effects, competition for nutrients, and to different physiological mechanisms that control the expression of several genes with minor effects.

When different gene groups are combined by hybridization, the expression of predominant genes for a trait must be known. This understanding is fundamental to the decisions made by breeders in the stages of cultivation and selection of segregating populations during the breeding program. Thus, the objective of this study was to determine the effects of combining ability and gene action for the root distribution traits of the Andean and Mesoamerican common bean gene groups. Six common bean parents from the Andean and Mesoamerican groups were hybridized in a complete diallel mating scheme, resulting in 30 F1 hybrids. The parents and hybrids were planted in the field in a simple lattice design. The target trait was root distribution, calculated as the relative number of roots in the topsoil. The effect of the general combining ability was significantly higher than that of the specific combining ability (58%) and the reciprocal effect (41%). Particularly, the combination estimates were modified according to the order of the gene groups used. The combinations IPR Uirapuru x BAF53 (Mesoamerican x Andean), BAF53 x CBS14 (Andean x Andean), and CBS14 x IPR Uirapuru (Andean x Mesoamerican) mainly exhibited an increase in the mean root distribution. However, the highest fraction of genetic variance correlated with additive components (60%), even in crosses involving different gene groups. Consequently, the additive gene action was predominant in the expression of root distribution trait in common bean, irrespective of the gene group used.

Anualmente, inúmeros cultivares de soja são desenvolvidos por programas de melhoramento genético. Desse modo, é importante obter informações sobre o comportamento desses cultivares em distintos ambientes. Objetivou-se com a elaboração do trabalho avaliar o efeito da interação genótipo*ambiente no desempenho de cultivares de soja em diferentes ambientes de cultivo. O delineamento experimental utilizado foi de blocos ao acaso com três repetições. Durante a execução dos experimentos, foi avaliado o desempenho produtivo de seis cultivares de soja em seis ambientes. A variável considerada foi o rendimento de grãos (kg ha-1). As informações foram submetidas a análise de variância, análise de regressão linear simples e teste de comparação de médias. A média geral de produtividade de grãos foi de 2960 kg ha-1. Aanálise de regressão indicou dois cultivares com adaptabilidade ampla, três cultivares com adaptabilidade específica a ambientes desfavoráveis e um cultivar com adaptabilidade específica a ambientes favoráveis. Dentre os cultivares avaliados, quatro apresentaram comportamento esperado ao longo dos ambientes de cultivo. Os cultivares exibiram comportamento análogo quanto ao rendimento de grãos. Por meio da aplicação da metodologia da regressão linear, foi possível obter informações relevantes para cultivo de soja em ambientes subsequentes.Palavras-chave: Glicine max L.; interação genótipo*ambiente; adaptabilidade; estabilidade. PERFORMANCE OF SOYBEAN CULTIVARS IN DIFFERENT GROWING ENVIRONMENTS ABSTRACT:Annually, numerous soybean cultivars are developed by breeding programs. Thus, is important to obtain information about of these cultivars behavior in different environments. The objective of this work was to evaluate the effect of the genotype * environment interaction on the performance of soybean cultivars in different growing environments. The experimental design used was randomized blocks with three replications. During the execution of the experiments, was evaluated the productive performance of six soybean cultivars in six environments. The trait considered was grain yield (kg ha-1). The information was submitted to analysis of variance, simple linear regression analysis and means comparison test. The overall mean grain yield was 2960 kg ha-1. Regression analysis indicated two cultivars with broad adaptability, three cultivars with specific adaptability to unfavorable environments and one cultivar with specific adaptability to favorable environments. Among the evaluated cultivars, four showed prospective behavior throughout the cultivation environments. The cultivars exhibited analogous behavior regarding grain yield. The application of the linear regression methodology provided relevant information for soybean cultivation in subsequent environments.Keywords: Glicine max L.; genotype*environment interaction; adaptability; stability.