Half a century of studying adaptability and stability in maize and soybean in Brazil

The study of adaptability and stability underlies the cultivar recommendation process for all crops. There is a considerable number of statistical methods available for this purpose, but little is known about their actual adoption by the Brazilian scientific community. The objective of this study was to carry out a systematic review of the scientific literature on the adaptability and stability methods used in maize and soybean in Brazil from scientific articles published between 1970 and 2017 in Brazilian journals. Article searches were carried out in journals indexed through the SciELO database. The articles were classified according to the year of publication and the adaptability and stability methods used. We also evaluated the pattern of association between methods. We found 113 articles on adaptability and stability in maize and soybean, in which 21 methods were listed. The most commonly used method was the Eberhart and Russell methodology. The Cruz, Torres, and Vencovsky along with the AMMI methods were also widely used. The number of articles using most methods decreased in the current decade, except for the GGE Biplot, MHPRVG, and Centroid methods. In studies with more than one method, the methods were more likely to be used together with the Eberhart and Russell methodology. Adaptability and stability in maize and soybean have been widely studied over the last several decades in Brazil, although the number of publications on this subject has decreased over this time period

Inoculation of maize with Azospirillum brasilense in the seed furrow 1 Inoculação do milho com Azospirillum brasilense no sulco de semeadura

ABSTRACT -Several studies addressing the inoculation of cereals with diazotrophic microorganisms can be found in the literature. However, in many experiments, investigators have overlooked the feasibility of applying these microorganisms to the furrow together with the seed, and the effect of bacterial concentration on phytostimulation. The aim of this work was to evaluate the effect of doses of an inoculant based on Azospirillum brasilense, applied to the seed furrow when planting maize, combined with different doses of nitrogen fertiliser. The experiment was carried out in the field, in soil of the cerrado region of Brazil. An experimental design of randomised blocks in bands was adopted, comprising nitrogen (40, 100, 200 and 300 kg ha -1 ) and doses of an A. brasilense-based liquid inoculant applied to the seed furrow (0, 100, 200, 300 and 400 mL ha -1 ). The dose of 200 mL ha -1 Azospirillum was noteworthy for grain production. This is the first report of the effective application of Azospirillum in the seed furrow when planting maize in the cerrado region of Brazil

Desenvolvimento e produtividade de grãos de milho submetido a níveis de desfolha

The objective of this work was to evaluate the influence of defoliation of maize on grain development and yield. Six trials were conducted in different growing seasons and locations and at two yield levels. A randomized complete block design was used, with seven replicates. Defoliation was made at the V4 vegetative stage of maize (four expanded leaves), and treatments consisted of: removal of the two basal leaves, removal of the four expanded leaves, total removal of leaves (aerial plant section), and a control (without defoliation). The following were evaluated: length of the vegetative period; and, at pre‑harvest, plant height, ear insertion height, plant lodging percentage, stalk‑breaking strength, force required to pull the plant, and yield. The removal of four leaves and the total removal of leaves increased the length of the vegetative period and reduced plant height, ear insertion height, and stalk strength against breaking. These defoliation levels also reduced yield, mainly with the total removal of leaves. The force required to pull the plant was not influenced by defoliation. Removal of four leaves and of all leaves reduces grain yield, respectively, in 6.25 to 14,05 in the evaluated hybrids.O objetivo deste trabalho foi avaliar a influência da desfolha do milho no desenvolvimento e na produtividade de grãos. Seis ensaios foram conduzidos em diferentes safras e locais e em dois níveis de produtividade. Utilizou-se o delineamento de blocos ao acaso, com sete repetições. A desfolha foi realizada no estádio vegetativo V4 do milho (quatro folhas expandidas), e os tratamentos foram: remoção das duas folhas basais, remoção das quatro folhas expandidas, remoção total das folhas (secção da parte aérea) e testemunha (sem desfolha). Foram avaliados: duração do período vegetativo; e, em pré‑colheita, altura de planta, altura de espiga, percentagem de plantas acamadas, força de quebramento de colmo, força de arranquio da planta e produtividade. A remoção das quatro folhas e a remoção total aumentaram a duração do período vegetativo e reduziram a altura de planta, a altura de espiga e a resistência do colmo ao quebramento. Esses níveis de desfolha também reduziram a produtividade, principalmente com a remoção total das folhas. A força de arranquio da planta não foi influenciada pela desfolha. A retirada de quatro folhas e do total das folhas reduz a produtividade de grãos, respectivamente, em 6,25 a 14,05% nos híbridos avaliados

microbeMASST: A Taxonomically-informed Mass Spectrometry Search Tool for Microbial Metabolomics Data

microbeMASST, a taxonomically informed mass spectrometry (MS) search tool, tackles limited microbial metabolite annotation in untargeted metabolomics experiments. Leveraging a curated database of >60,000 microbial monocultures, users can search known and unknown MS/MS spectra and link them to their respective microbial producers via MS/MS fragmentation patterns. Identification of microbe-derived metabolites and relative producers without a priori knowledge will vastly enhance the understanding of microorganisms’ role in ecology and human health

A Taxonomically-informed Mass Spectrometry Search Tool for Microbial Metabolomics Data

MicrobeMASST, a taxonomically-informed mass spectrometry (MS) search tool, tackles limited microbial metabolite annotation in untargeted metabolomics experiments. Leveraging a curated database of >60,000 microbial monocultures, users can search known and unknown MS/MS spectra and link them to their respective microbial producers via MS/MS fragmentation patterns. Identification of microbial-derived metabolites and relative producers, without a priori knowledge, will vastly enhance the understanding of microorganisms’ role in ecology and human health

Adaptability and stability: systematic review and application

A interação genótipos x ambientes (GxA) é um dos principais desafios enfrentados no melhoramento de plantas, pois causa inconsistências no ranqueamento de genótipos entre os ambientes. Consequentemente, a interação GxA dificulta o processo de seleção e recomendação de cultivares. Para minimizar, e até aproveitar, os efeitos da interação GxA, têm sido propostas ao longo dos anos diversas metodologias estatísticas para o estudo da adaptabilidade e estabilidade dos genótipos. Visto isso, o objetivo deste trabalho foi estudar a adoção dos métodos para estudo da adaptabilidade e estabilidade nas duas principais culturas agrícolas brasileiras, milho e soja, e aplicar algumas dessas metodologias em dados de milho provenientes do leste africano. Inicialmente, foi realizada uma revisão sistemática da literatura científica para verificar a adoção dos métodos em artigos sobre milho e soja publicados desde 1970 em revistas brasileiras indexadas na base de artigos SciELO. Foram encontrados 113 artigos (38 sobre soja e 75 sobre milho), nos quais foram listados 21 métodos de adaptabilidade e estabilidade. O método utilizado com maior frequência em ambas as culturas foi Eberhart e Russell. Os métodos Cruz, Torres e Vencovsky e Modelo de efeitos principais aditivos e interação multiplicativa (AMMI) também foram amplamente adotados. Em geral, o número de publicações com a maioria dos métodos reduziu na presente década, exceto com GGE Biplot, Média harmônica da performance relativa dos valores genotípicos (MHPRVG) e Centroide, que apresentaram crescimento. Posteriormente, após a realização da revisão sistemática, aplicaram-se os métodos GGE Biplot e Cruz, Torres e Vencovsky em conjuntos de dados de experimentos realizados em 2017 no leste da África (Quênia, Uganda e Tanzânia) pelo Centro Internacional de Melhoramento de Milho e Trigo (CIMMYT). Os ensaios abrangeram 24 locais bem irrigados (condições ótimas) e sete locais em condições de déficit hídrico, nos quais foram avaliados 65 híbridos de milho de ciclo intermediário e 55 de ciclo precoce. O método GGE Biplot permitiu identificar o melhor e pior local para seleção de híbridos em condições ótimas, respectivamente Kakamega e Kabuku. Não foi possível definir os melhores e piores locais para condições de estresse hídrico, pois estes foram altamente dependente da maturidade dos híbridos. Utilizando-se os dois métodos, GGE Biplot e Cruz, Torres e Vencosvky, foi possível identificar com segurança os híbridos precoces E14, E2 e E23 e os intermediários I35, I18, I21 e I41 como os mais bem adaptados simultaneamente a condições ótimas e a condições de estresse hídrico. Embora o número de publicações sobre adaptabilidade e estabilidade tenha reduzido nos últimos anos, essa área de pesquisa continua ativa e relevante no Brasil. Além disso, a aplicação dos métodos de estudo da adaptabilidade e estabilidade fornece informações e direcionamentos fundamentais ao processo de melhoramento de plantas.The genotype by environment (GE) interaction is a huge challenge to the plant breeding as it may cause inconsistencies in the ranking of genotype across environments. Thus, the GE interaction makes the selection and recommendation of cultivars difficult. To minimize and even take advantage of the effects of GE interaction, many statistical methods have proposed to study the stability of genotypes. The objectives of this work were to study the adoption of the stability methods in soybean and maize, the main crops in Brazil, and to apply some of these methods on a dataset from Eastern Africa. First, it was done a systematic review to verify the adoption of the stability methods in articles about soybean and maize published since 1970 in Brazilian scientific journals indexed by SciELO. It was found 113 articles (38 about soybean and 75 about maize), in which 21 stability methods were listed. Eberhart and Russell method was the most frequently used. Cruz, Torres and Vencovsky and The Additive Main Effects and Multiplicative Interaction (AMMI) methods were widely adopted as well. In general, the number of publications related to most methods has decreased in the last decade, except GGE biplot, Harmonic mean of the relative performance of the genetic values (MHPRVG) and Centroid methods, which showed increase. Them, it was applied GGE biplot and Cruz, Torres and Vencovsky on an experimental dataset from Eastern Africa (Kenya, Uganda and Tanzania. These trials were performed by International Maize and Wheat Improvement Center (CIMMYT) in 2017. A total of 55 early maturing and 65 intermediate maturing maize hybrids were selected for these studies. The hybrids were evaluated in 24 well-watered (WW) and 7 drought stress (DS) locations. In WW conditions, GGE biplot was able to identify Kakamega as the best location to select hybrids and Kabuku as the worst location. However, the best and worst locations to select hybrids to drought stress conditions were highly dependent on hybrid maturity. Using both methods, GGE biplot and Cruz, Torres and Vencovsky, it was possible to identify confidently the early maturity hybrids E14, E2 and E23 and the intermediate maturity hybrids I35, I18, I21 and I41 as well adapted to both WW and DS conditions. Although the number of publication on stability has decreased in recent years, this research topic remains active and relevant in Brazil. In addition, the use of stability methods provides key information and guidance for plant breeding.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Implications of early defoliaton and chemical protection to maize white spot in maize

Maize is one of the main crops in Brazil and the world, and its production is highly demanded for human and animal consumption. Maintenance of leaf integrity is required by the crop to reach high yield. Therefore, this study evaluated the effect of defoliation at the beginning of the crop cycle and the combination of fungicides to control white spot disease in maize. This study was divided into two trials. The first one evaluated the effect of defoliation in vegetative stage V4 on maize development and yield. Six experiments were conducted in different years and locations, representing different environments, besides different investment levels. The experimental design was randomized complete block with four defoliation levels (treatments), and seven replicates. Defoliation was performed manually in maize vegetative stage V4, with treatments consisting of removal of the two basal leaves, removal of four fully expanded leaves, plant section (removal of all leaves), besides a control. Duration of vegetation period and, previously to harvest, plant height, main ear insertion height, breaking strength of stalk, force required to pull the plant and kernel productivity were evaluated. It can be concluded that removal of four leaves and the section of the plant in V4 stage hinders plant growth, delays flowering and greatly reduces yield. The second study evaluated combination of fungicides to control maize white spot and maize response to chemical protection in field conditions. Four experiments were done in different years and locations. The experimental design was randomized blocks with seven treatments and six replications. The treatments were: dithiocarbamate with two or three applications, strobilurin + triazole with two or three applications, strobilurin + triazole + dithiocarbamate with two or three applications and a control treatment (without fungicide). White spot severity of maize was evaluated for the calculation of AUDPC, percentage of green leaf area at the end of the crop cycle, stem integrity (stalk density, stalk breaking strength, breaking height and angle), percentage of rotten kernels and kernel yield. It can be concluded that the combination of dithiocarbamate and the pre-mix of strobilurin and triazole, with two or three applications, was effective to control the maize white spot. The use of three applications of dithiocarbamate is also effective in controlling this disease. The effective treatments to control maize white spot also provided greater green leaf area, greater stalk integrity and yield. The maintenance of leaf area is important throughout the crop cycle for the expression of its yield potential, and the use of fungicides contributes for this maintenance.Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorMestre em AgronomiaA cultura do milho é uma das principais culturas agrícolas do Brasil e do mundo, e sua produção é altamente demandada para alimentação humana e animal. Para que a cultura atinja altas produtividades, é necessária a manutenção da integridade foliar. Visto isso, o objetivo deste trabalho foi avaliar a influência da desfolha no início do ciclo da cultura do milho e a combinação de fungicidas para o controle da doença mancha branca do milho. Este trabalho foi dividido em duas pesquisas. A primeira pesquisa avaliou a influência da desfolha no estádio vegetativo V4 sobre o desenvolvimento e rendimento da cultura do milho. Para tanto, seis experimentos foram conduzidos em diferentes anos e locais, representando diferentes ambientes, além de diferentes níveis de investimento. O delineamento experimental foi em blocos casualizados, com quatro tratamentos, compostos por níveis de desfolha, e sete repetições. A desfolha foi realizada manualmente no estádio vegetativo V4 do milho, sendo os tratamentos compostos por retirada das duas folhas basais, retirada das quatro folhas completamente expandidas, secção da planta (remoção de todas as folhas), além de uma testemunha. Avaliaram-se a duração do período vegetativo e, em pré-colheita, altura de planta, altura de inserção da espiga principal, força de quebramento de colmo, força de arranquio da planta e produtividade de grãos. Concluiu-se que a retirada de quatro folhas e a secção da planta no estádio V4 prejudicam o crescimento da planta, atrasa o florescimento e reduz consideravelmente a produtividade da cultura. A segunda pesquisa avaliou combinações de fungicidas no controle da mancha branca e a resposta da cultura à proteção química em condições de campo. Para tanto, foram conduzidos quatro experimentos em diferentes anos e locais. O delineamento experimental foi em blocos casualizados, com sete tratamentos e seis repetições. Os tratamentos foram: ditiocarbamato com duas e três aplicações, estrobilurina + triazol com duas e três aplicações, ditiocarbamato + estrobilurina + triazol com duas e três aplicações e um tratamento testemunha (sem aplicação de fungicida). Avaliaram-se a severidade da mancha branca para o cálculo da AACPD, porcentagem de área foliar verde ao final do ciclo da cultura, integridade de colmo (densidade de colmo, força de quebramento do colmo, altura de quebramento e ângulo de quebramento), porcentagem de grãos ardidos e produtividade de grãos. Concluiu-se que a combinação de diotiocarbamato mais a mistura pronta de estrobilurina e triazol, com duas ou três aplicações, é eficaz para o controle da mancha branca. O uso de três aplicações de diotiocarbamato também é eficaz no controle dessa doença. Os tratamentos eficazes no controle da mancha branca também proporcionam maior área foliar verde no final do ciclo da cultura, maior integridade de colmo e produtividade. A manutenção da área foliar é importante durante todo o ciclo da cultura para a expressão do seu potencial produtivo, e o uso de fungicidas contribui para essa manutenção

Inoculation of maize with Azospirillum brasilense in the seed furrow

ABSTRACT Several studies addressing the inoculation of cereals with diazotrophic microorganisms can be found in the literature. However, in many experiments, investigators have overlooked the feasibility of applying these microorganisms to the furrow together with the seed, and the effect of bacterial concentration on phytostimulation. The aim of this work was to evaluate the effect of doses of an inoculant based on Azospirillum brasilense, applied to the seed furrow when planting maize, combined with different doses of nitrogen fertiliser. The experiment was carried out in the field, in soil of the cerrado region of Brazil. An experimental design of randomised blocks in bands was adopted, comprising nitrogen (40, 100, 200 and 300 kg ha-1) and doses of an A. brasilense-based liquid inoculant applied to the seed furrow (0, 100, 200, 300 and 400 mL ha-1). The dose of 200 mL ha-1Azospirillum was noteworthy for grain production. This is the first report of the effective application of Azospirillum in the seed furrow when planting maize in the cerrado region of Brazil