ABSTRACT. Organic agriculture systems have the nutrients supplied by plant or animal by-products, bioinoculants, and compost-based products as earthworm composts and green manures. However, the quantitative and qualitative parameters of soil amendments depend on their sources, and soil amendments are generally not sufficient to supply the nutritional requirements of maize crops. Moreover, specialty maize requires high levels of N. Thus, the aim of this study was to investigate specialty maize varieties supplied with two microbial inoculants applied in two inoculation methods. These factorial treatments were compared with their checks (varieties without inoculation), and the interaction among these factors was also investigated. The trials were carried out during the growing season in 2017-2018 in the State University of Maringá. The popcorn trial followed the randomized complete block design where the factorial 3 × 2 × 2 + 3 had five replications. The trial with white grits maize followed the same experimental design but the factorial scheme was 2 × 2 × 2 + 2 with three replications. Both trials had maize varieties and two species of microbial inoculants (Azospirillum brasilense and Methylobacterium sp.) applied in two inoculation methods, in the seeds and the foliar spray at V4 stage of plant development. The response traits were grain yield and the components of crop production. In both trials, we verified that the majority of the interactions among the factors was non-significant (p > 0.05), indicating the independence of these factors. Furthermore, the microbial inoculants had no beneficial effects on the traits. The possibility of a higher crop yield did not confirm the application of the inoculant in the stage V4. The organic compost may be the key point in mitigating the treatments with microbial inoculants due to the availability of N in the first stages of plant development. The traits also suggest the necessity of more trials about the influence of microbial inoculants on specialty maize production.

Abstract: The seedling traits is a simple and non-destructive methodology used to identify haploids/diploids in maize. This study aimed at establishing an optimal germination temperature to evaluate this methodology and verify its effectiveness. Haploid and diploid seeds, obtained from crosses with the haploidy inducer TAIL9, were classified using the R1-Navajo marker and placed to germinated in growth chambers maintained at different temperatures. After 96 h, radicle and coleoptile lengths and the number of lateral seminal roots were determined. Cut-off points for these traits were established using Receiver Operating Characteristic curves and a new haploid/diploid classification was performed and compared to the plant phenotype (gold standard) to obtain false discovery rates and false negative rates. The seedling traits methodology successfully differentiated haploids and diploids, proving to be effective in eliminating false positives, selected by the R1-Navajo marker. The temperature of 30 °C was established as the optimal germination temperature for this study.

Resumo: O objetivo deste trabalho foi avaliar as influências dos fatores genótipos de milho (Zea mays), safras agrícolas, texturas dos endospermas, fundo genético e bases genéticas nas taxas de haploides putativos (THPs), conforme a expressão do gene R1-navajo (R1-nj). Foram avaliados 41 genótipos de milho como receptores de pólen, em cruzamentos com o indutor “Krasnodar haploid inducer”, em duas safras (verão e inverno), no município de Maringá, no estado do Paraná, Brasil. O delineamento experimental foi o inteiramente casualizado com dez repetições (espigas). A variável resposta analisada foi a THP determinada pela proporção de haploides putativos, obtidos com base no marcador R1-nj, em relação ao número de sementes diploides por espiga. Posteriormente, foram utilizados modelos lineares generalizados para escolher o mais adequado para explicar a THP em função dos fatores testados. As safras, os genótipos e a interação safras x genótipos afetaram significativamente a THP, o que evidencia a dependência destes fatores na expressão do marcador fenotípico baseado na pigmentação por antocianina e determinado pelo gene dominante R1-nj. O número de agrupamentos formados pelos genótipos foram diferentes em cada safra. Dez genótipos apresentaram taxas maiores no verão do que no inverno. As texturas dos endospermas, as bases genéticas e o fundo genético não interferiram na THP.

Abstract: The objective of this work was to evaluate the influences of the factors corn (Zea mays) genotypes, crop seasons, endosperm texture, genetic background, and genetic basis on putative haploid rates (PHRs) according to the expression of gene R1-navajo (R1-nj). Forty-one corn genotypes were evaluated as pollen receptors, in crosses with the Krasnodar haploid inducer, in two crops (summer and winter), in the municipality of Maringá, in the state of Paraná, Brazil. The experimental design was completely randomized with ten replicates (ears). The response variable analyzed was the PHR, determined by the proportion of putative haploids, obtained through the R1-nj marker, in relation to the number of diploid seeds in each ear. Subsequently, generalized linear models were used to choose the one best fit to explain the PHR in function of the tested factors. Crop seasons, genotypes, and the crop seasons x genotypes interaction affected significantly the PHR, showing the dependence of these factors on the expression of the phenotypic marker based on anthocyanin pigmentation and determined by gene R1-nj. The number of clusters formed by the genotypes was different in each crop season. Ten genotypes showed higher rates in summer than in winter. Endosperm texture, genetic basis, and genetic background did not affect the PHR.

ABSTRACT. Statistics is the main science by which researchers validate the results of scientific work, and the choice of an inadequate statistical method may lead to conclusions that are considered questionable by reviewers. This study had the objective of describing the characteristics of the statistical methods used in the papers published in Acta Scientiarum. Agronomy from 1998 to 2016 as part of a a critical analysis of the journal to pinpoint possible failures in the application of these methods. All scientific articles (n = 1,237) published in the journal were surveyed, of which 54.1% addressed areas of crop production. The mean comparison methods were the most commonly used (75.5%) and, consequently, they represented the highest proportion of errors (60.8%) of the authors in the journal.