Genetic variability is essential for maize breeding, being source of determining alleles and genes that maximize traits of agronomic interest, minimize abiotic and biotic stresses, as germplasm sources for breeding, one can use landraces, adapted populations, exotic populations and commercial hybrids, which are readily available to lineages extraction and improved open pollinated varieties (OPVs). Thus, the aim of this review is to highlight the main dynamics involved in the genetic improvement of maize, the use of biometric models to select genotypes superior to grain yield and nutritional components. In this study it was possible to contextualize on: Botanical description, morphological and physiological characteristics, the genetic breeding, development of inbred lines, development of hybrids, variance components and genetic parameters, heterosis, diallel analysis, genotype x environment interaction, associations between traits and Restricted Maximum Likelihood and Best Linear Unbiased Predictor (REML / BLUP).

This study investigated the effects of potting media on seed germination and early seedling growth of Pterocarpus erinaceus Poir at the Forestry Nursery in Jos, Nigeria. Using Completely Randomized Design (CRD) with three replicates, laboratory-tested soil samples, top soil, sharp sand, sharp sand + top soil, sharp sand + top soil + cow dung and sharp sand + top soil + poultry droppings were used in various combinations to assess the growth parameters of P. erinaceus (germination percentage, emergence, plant height, number of leaves, length of leaves and stem diameter) for 12 weeks. Descriptive and inferential statistics were employed to analyze collected data. Result indicated that sharp sand + top soil + poultry droppings had the highest nitrogen concentration (2.19%), sharp sand + top soil + cow dung (2.07%), sharp sand + top soil (1.50%), top soil (0.72%) and Sharp sand (0.38%). Potting media with poultry droppings recorded an overall higher percentage germination of 42.9% by the end of the germination period. Analysis of variance (ANOVA) of collected data on combined soil aggregate on growth parameters indicated a significant (p<0.05) difference in plant height, number of leaves, leaf length and stem diameter. Potting with poultry dropping gave the best potting media growth results when compared to other treatments that enhanced seed germination and seedling growth of P. erinaceus. This superior observation of the poultry droppings incorporated potting mixtures over the cow dung provides an outstanding potentials to enhance P. erinaceus plantation establishment. Consequently, recommended for raising seedlings in the nursery as well as ensuring sustainable management.

The study had the purpose to evidence the agronomic performance, inter-relations of characters and the multivariate differentiation of soybean genotypes cultivated in the preferential season, in the state of Rio Grande do Sul, Brazil. In the crops season of 2017/2018, The experimental design was the completely randomized blocks, being 25 genotypes with three replicates. The data obtained was submitted to presuppositions based on normality and homogeneity of residual variances, variance analysis, Tocher method, Euclidian algorithm, linear correlations, relative contribution of characters by Singh and artificial neural networks. The agronomic performance of the genotypes presents superior seeds yield per plant through the elevated magnitude of reproductive nodes, legumes and seeds per plant. The plant height of the soybean is positively associated with the number of total nodes and reproductive nodes in the main stem and branches, where they are directly linked with the soybean productive potential. The most polymorphic characters correspond to the number and mass of thousand seeds, being possible to differentiate in a multivariate way the soybean genotypes though the similarity profiles.

No abstract

As adequadas práticas em campos de produção de sementes e grãos, são de fundamentais para se atingir altas produtividades. O uso de sementes de alta qualidade, bem como um correto manejo nutricional da cultura são pilares para se atingir elevadas produtividades. Sendo assim, este trabalho objetivou avaliar o desempenho da soja no Noroeste do Estado do Rio Grande do Sul, submetida a diferentes doses e fontes de adubação de base. Os tratamentos consistiram nas seguintes combinações: 350 de organomineral (T1), 350 de mineral (T2), 530 de organomineral (T3), 210 de organomineral + 230 de cloreto de potássio (T4), 210 de mineral + 230 de cloreto de potássio (T5) e 440 de organomineral + 230 Kg/ha de cloreto de potássio (T6). O delineamento experimental utilizado foi o de blocos casualizados, sendo avaliado os componentes de rendimento e a qualidade fisiológica das sementes produzidas. Os melhores resultados nos tratamentos T3 e T5, ambos os tratamentos diferiam tanto na fonte quanto na dose da adubação. Não foram observadas grandes diferenças entre os tratamentos que receberam na adubação de base fertilizantes minerais ou organominerais, o que torna os fertilizantes organominereais uma opção a ser levada em conta pelo produtor. O aumento de doses de adubação potássica e fosfatada não levou a um aumento de vigor das sementes de soja.Palavras chaves: Glycine max, componentes de rendimento, crescimento de plantas, vigor das sementes.