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Nitrogen is the most required and complex management element in maize crop, promoting the highest responses in crop yield. The objective of this work was to verify the effect of different N sources on topdressing in minimum tillage and conventional tillage systems on the agronomic performance of the Pioneer 32R22YHR single cross and on the severity of common rust disease. Two experiments were carried out in a randomized block design (DBC) in the 2013/14 crop in minimum tillage and conventional tillage systems. The treatments were: control without nitrogen, ammonium sulfate, urea, ammonium nitrate, a physical mixture of nitrate (70%) and ammonium sulfate (30%) and a chemical mixture of these same sources in the same proportion just explained. Nitrogen sources had no significant effect on plant height, ear insertion height, ear prolificacy, grain yield and leaf severity of common rust, regardless of the sowing system. Under conventional tillage, the plants presented higher plant height, ear insertion and grain yield. There was no effect of sowing systems on prolificacy. With the exception of nitrogen free treatment, for all others, the severity of common rust was higher in minimum tillage system.

The aim of this study was to investigate the effect of treatment with insecticides and fungicides on the physiological quality of corn seeds, classified in sizes, in different periods of storage. Seeds of the hybrid BM915 PRO, classified in two sizes (CH20/64 and CH24/64), were treated with a mixture of carbendazim + thiram (Derosal Plus®), pirimiphos methyl (Actellic®), deltamethrin (K-obiol®), and water (standard treatment). In addition to the standard treatment adopted by the company, treatments with clothianidin (Poncho®), thiamethoxam (Cruizer®), and fipronil (Shelter®) were added to the spray mixture. The seeds were stored in a non-climate-controlled environment in multi-ply paper packages. The physiological quality of the seeds was evaluated every ninety days over a period of 270 days by the germination test, cold test, and accelerated aging. Sanitary quality was also evaluated through the Blotter test. The physiological quality of seeds of the hybrid BM915 PRO is maintained up to ninety days of storage, regardless of the chemical treatment used and the size of the seeds. The addition of the insecticide to the standard treatment used in chemical seed treatment does not affect the action of the fungicides on the fungi in the seeds. Resumo: Objetivou-se verificar a interferência do tratamento com inseticidas e fungicidas sobre a qualidade fisiológica de sementes de milho, classificadas em dois tamanhos, em diferentes períodos de armazenamento. Sementes do híbrido BM915 PRO, classificadas em dois tamanhos (CH20/64 e CH24/64), foram tratadas com calda caracterizada pela mistura de Carbendazim + Thiram (Derosal Plus®), Deltametrina (Actellic®), Pirimifós metílico (K-obiol®) e água (tratamento padrão). Além do tratamento padrão adotado pela empresa, foram acrescentados à mistura da calda tratamentos com clotianidina (Poncho®), tiametoxam (Cruizer®) e fipronil (Shelter®). As sementes foram armazenadas em ambiente não climatizado em embalagens de papel multifoliado. A qualidade fisiológica das sementes foi avaliada, a cada noventa dias, por um período de 270 dias por meio do teste de germinação, teste de frio e envelhecimento acelerado. Foi avaliada, ainda, a qualidade sanitária por meio do Blotter test. Concluiu-se que a qualidade fisiológica das sementes do híbrido BM915 PRO é mantida até os noventa dias de armazenamento, independente do tratamento químico utilizado e do tamanho das sementes. A adição do inseticida ao tratamento padrão utilizado no tratamento químico das sementes não afeta a ação dos fungicidas sobre os fungos presentes nestas.

Abstract: The formononetin biostimulant may be an option for reducing P fertilization once it stimulates mycelial growth of arbuscular mycorrhizal fungi and increases plant ability to take up nutrients through the roots, especially phosphorus. The objective of this study was to evaluate the effect of formononetin associated with phosphorus fertilization in maize. Field experiments were conducted in a randomized block design with a 3 × 4 factorial arrangement (0, 50 or 70, and 140 kg ha-1 P2O5; and formononetin application rates: 0, 25, 50, and 100 g ha-1), with four replications. Formononetin (100 g ha-1) increased the mycorrhizal colonization rate up to 30% in maize in the first four weeks after emergence when no P fertilizer was applied, and to 17% when 50 or 70 kg ha-1 of P2O5 were applied. The application of 50 and 100 g ha-1 of formononetin significantly increased plant height, ear height, and grain yield (22% - 76%) when no P fertilizer was applied. The use of formononetin in the field stimulates mycorrhizal colonization, has a positive effect on maize yield, and reduces the need for P fertilizer application in maize. However, this effect was evident only at low P soil contents.

Water deficit stress is the abiotic factor with the highest impact on crop yield. The objective of this study was to evaluate grain yield (GY), the anthesis-silking interval (ASI) and drought tolerance indices in maize hybrids. We evaluated GY and the ASI of 86 hybrids under two moisture levels (normal irrigation and water stress) for three consecutive years. The stress susceptibility index, water stress tolerance, drought resistance coefficient, drought resistance index, stress tolerance index and harmonic mean were evaluated. There were significant hybrid x environment interactions for GY and the ASI. Differences in the ASI among environments ranged from 0 to 5 days. The hybrids P3862, 1I873, 1I923, 1I862 and 1J1211 showed high GY, associated with the highest drought tolerance indices. The stress tolerance index and harmonic mean indices can be used to identify higher-yielding maize hybrids in environments with and without water restriction.

One of the main barriers to the production of hybrid maize seeds consists of needing detasseling of female parent in order to avoid contamination with unwanted pollen. This activity is a laborious practice, which makes the production more expensive and promotes productive losses. Thus, the use of cytoplasmic genetic male sterility can facilitate the hybridization process, and consequently, the production of hybrid seeds. The objective of this study was compare grain yield in maize hybrids produced from the combination of two testers with five distinct lines of cytoplasm C “Charrua” versus the isogenic of fertile cytoplasm. Twenty common hybrids were evaluated in relation to grain crops and resistance to leaf diseases, white spot and gray leaf spot. The experiments were carried out during summer season of 2015/2016 and winter season of 2016. The use of lines with cytoplasm C was observed and it is promising since it did not affect the agronomic performance of hybrids, regardless of environment, crop season, parental and tester used. Therefore, cytoplasm C can be used as an excellent source of cytoplasmic genetic sterility in the production of hybrid seeds in seed companies that want to decrease the use of detasseling practice. Key words: Zea mays L, production of seeds, detasseling.

The identification of genotypes presenting wide adaptability and stability is pivotal in breeding programs. To identify such genotypes, it is necessary to use sophisticated analytical tools to establish the genotypes × environments interaction (GEI) pattern across multi-environment trials and select for genotypic stability and adaptability. The aim of the present study was to estimate GEI using Bayesian analysis of Additive Main Effects and Multiplicative Interaction (AMMI) models for both balanced and unbalanced data sets and estimate the predictive ability of model. Two studies were assessed to showcase this approach; in the first, 10 commercial maize (Zea mays) single-cross hybrids and 45 double-cross hybrids were evaluated at 15 different locations. In the second study, 28 hybrids were evaluated in 35 different environments distributed over two different harvest seasons (first and second harvests) with unbalanced data sets within and between harvests. The Bayesian analysis of the AMMI models was robust in dealing with the unbalanced data. This approach is promising for the identification of interaction patterns and the estimation of GEI. The genotypes and environments could be grouped according to their interaction patterns even using the unbalanced data sets, showing that Bayesian analysis of AMMI models could be applied effectively for multi-environment trials. The prediction for missing hybrids was satisfactory in a simulated unbalanced design and captured the GEI and patterns in the data. This allowed the direct comparison of genotypes from the first and second harvests and the estimation of selection gain.

The identification of causal regions associated with resistance to Fusarium verticillioides can be useful to understand resistance mechanisms and further be used in breeding programs. In this study, a genome-wide association study (GWAS) was conducted to identify candidate markers associated with resistance to the ear rot caused by the fungus F. verticillioides. A total of 242 maize inbred lines were genotyped with 23,153 DArT-seq markers. A total of 12 DArTs were associated with ear rot resistance. Some DArTs were localized close to genes with functions directly related to ear rot resistance, such as a gene responsible for the innate immune response that belongs to the class of NBS-LRR receptors. Some markers were also found to be closely associated with genes that synthesize transcription factors (nactf11 and nactf61), genes responsible for the oxidation-reduction process and peroxidase activity. These results are encouraging since some candidate markers can present functional relationship with ear rot resistance in maize.

The diversity analysis and screening of major genes using genomewide association studies (GWAS) for quantitative traits have been exploited in several grass crops, but in maize it has been neglected. This study was conducted to evaluate the genetic diversity of a collection of lines and the potential of genomic analysis as an initial screening tool. For this purpose, a collection of 470 maize inbred lines were genotyped with 23,153 Dart-seq markers. The genomewide analysis of ear weight was used aiming to perform an initial screening in our germplasm. The diversity analysis allowed the lines to be separated into distinct groups, and most of the lines were in agreement with previous pedigree information. The GWAS revealed ten regions potentially associated with the ear weight trait, one of which was related to drought stress. The results of a multiple marker analysis confirmed four of these regions, presenting a predictive accuracy of 0.6. Based on the molecular data and the results of GWAS, it is possible to infer the potential use of this genetic background for breeding.

The objective of this study was to evaluate gene expression related to water deficit tolerance in maize lines. For this, lines previously classified as tolerant (91-T and 32-T) and non-tolerant (24-NT and 57-NT) to water deficit were used. The seeds of the four lines were evaluated for emergence and emergence speed index, and the seedlings were evaluated for root and shoot length under two conditions of water availability (70 and 10% substrate water retention capacity). In transcript analysis, the expression of several genes associated with water deficit tolerance, ZmDBP3, ZmALDH9, ZmAN13, and ZmDREB2A, was evaluated by qRT-PCR for the 91-T and 57-NT lines. It can be concluded that soil water deficiency did not reduce root development. However, the shoot length was significantly lower under dry conditions. Through transcript analysis, the genes ZmDBP3 and ZmAN13 were identified as potential markers for the early selection of maize lines tolerant to water deficit.

Knowing genes related to water deficit is a valuable tool to assist and accelerate the selection process of maize genotypes more adapted to drought conditions. Therefore, this work aimed to evaluate genes expression related to tolerance to water deficit in maize lines, using proteomic and transcriptomic analyses. Two lines previously classified as tolerant (91-T) and non-tolerant (57-NT) to low water availability were used. Dried seeds, ears tips, and seedlings (collected at three, five, and seven days after sowing) of the two maize lines (91-T and 57-NT) were used in proteomic analyses. Seedlings were subject to two contrasting water-availability conditions (70% and 10% of the water retention capacity). The expression of catalase, peroxidase, and esterase enzymes and heat-resistant proteins were evaluated by electrophoresis. Dried seeds, ears tips, and seedlings (collected at seven days after sowing, subject to two contrasting water-availability conditions) of two maize lines (91-T and 57-NT) were used in the transcriptomic analyses. The expression of genes associated with tolerance to low water availability (ZmPP2C, ZmLEA3, and AOX2) was evaluated by the qRT-PCR technique. Results revealed that catalase, peroxidase, and esterase enzymes had a higher expression on the ears tips of the 91-T line. The expression of catalase and esterase enzymes reduced in seven-day-old seedlings in the two lines analyzed. Heat-resistant proteins had greater activity on the dried seeds of the 91-T line. The AOX2 gene was identified as a potential marker for the selection of maize genotypes tolerant to water deficit. RESUMO O conhecimento de genes relacionados ao déficit hídrico é uma importante ferramenta visando auxiliar e acelerar o processo de seleção de genótipos de milho mais adaptados às condições de seca. Diante disso, objetivou-se neste trabalho avaliar a expressão de genes relacionados à tolerância ao déficit hídrico em linhagens de milho, por meio das análises proteômicas e transcriptômicas. Para isso, foram utilizadas duas linhagens previamente classificadas como tolerante (91-T) e não tolerante (57-NT) a baixa disponibilidade hídrica. Para as análises proteômicas, utilizaram-se sementes secas, ponta de espigas e plântulas coletadas com três, cinco e sete dias após a semeadura, sendo as plântulas submetidas a duas condições contrastantes quanto a disponibilidade hídrica (70% e 10% da capacidade de retenção de água). Avaliou-se a expressão das enzimas catalase, peroxidase, esterase e das proteínas resistentes ao calor por meio da técnica de eletroforese. Sementes secas, ponta de espigas e plântulas (coletadas sete dias após a semeadura, submetidas a duas condições de disponibilidade hídrica) de duas linhagens de milho (91-T e 57-NT) foram utilizadas para as análises transcriptômicas. A expressão dos genes associados a tolerância a baixa disponibilidade hídrica (ZmLEA3, AOX2 and ZmPP2C) foi realizada pela técnica de qRT-PCR. Pode-se concluir que houve maior expressão em ponta de espigas na linhagem 91-T para as enzimas catalase, peroxidase e esterase. Para as enzimas catalase e esterase, as plântulas de sete dias de desenvolvimento apresentaram uma redução da expressão, nas duas linhagens analisadas. Maior atividade das proteínas resistentes ao calor ocorreu nas sementes secas da linhagem 91-T. Identificou-se o gene AOX2 como um potencial marcador para seleção de genótipos de milho tolerantes ao déficit hídrico.

RESUMO - A preocupacao a respeito do fluxo genico entre lavouras de milho transgenicas e convencionais tem recebi-do cada vez mais atencao no âmbito tecnico e politico no Brasil. Diante disso, objetivou-se, com este trabalho, estimar o fluxo genico em lavouras comerciais de milho, bem como estabelecer um tamanho de amostra adequado para estimar a taxa de contaminacao por transgenicos nos campos convencionais de milho com o uso de amostragem sistematica. As coletas das amostras foram realizadas em campos de producao de graos comerciais nos municipios de Itumirim e Madre de Deus, MG, na safra 2010/2011 e na cidade de Ingai, MG, na safra 2011/2012. Foram coletadas amostras em cinco distâncias do campo convencional em relacao ao campo de transgenicos: 5 m, 10 m, 20 m, 50 m e 100 m. Foram tambem coletados quatro diferentes tamanhos de amostra: 1 espiga, 5 espigas, 10 espigas e 15 espigas em quatro re-peticoes. Apos as coletas, retirou-se de cada amostra uma aliquota de 300 sementes para realizacao do PCR em tempo real para a estimacao do fluxo genico. Nao houve diferenca significativa entre os diferentes tamanhos analisados nos tres locais. Em Itumirim e em Madre de Deus, tambem nao houve diferenca entre as distâncias analisadas; ja no campo do municipio de Ingai, as amostras coletadas na distância de 10 m apresentaram maior taxa de contaminacao. Em todos os campos, a contaminacao media ficou abaixo de 1%. Palavras-chave: Zea may L, transgenico, contaminacao. ANALYSIS OF GENE FLOW IN MAIZE UNDER DIFFERENT SAMPLE SIZES AND SAMPLING DISTANCES ABSTRACT – The concern about gene flow between transgenic and conventional maize farming has been received increasing attention in technical and political scope in Brazil. Thus, the objective of this work was to estimate the gene flow in commercial maize farms, as well as the establishment of an adequate sample size to estimate the contamination rate by transgenic in conventional maize fields, using systematic sampling. The samples collections were carried out in fields of grain commercial production in the Itumirim and Madre de Deus municipalities, both in Minas Gerais state, in 2010/2011 crop season and in Ingai, also Minas Gerais state, in 2011/2012 crop season. Samples were collected at five distances between conventional and transgenic field: 5, 10, 20, 50 and 100 m. Four different sample sizes were also collected: 1, 5, 10 and 15 spikes, with four replications. After collection, a portion of 300 seeds of each sample was used in a real-time PCR for the gene flow estimation. There was no statistical difference among the different sample sizes analyzed at the three sites. In Itumirim and Madre de Deus also no statistical difference was observed among the distances analyzed; the samples collected in Ingai field in a distance of 10 m had a higher rate of contamination by transgenics when compared to the other samples. The average contamination was below of 1% in all fields. Palavras-chave: Zea mays, transgenic, contamination.

The study was conducted on dry maize seed and seed subjected to sub optimal germination temperature. Four lines of maize seeds were used, two were classified as susceptible to low temperature (44 and 54) and two tolerant to low temperature (64 and 91°C). Water content and germination tests were performed at different temperatures (10 and 25°C) to evaluate the physical and physiological quality of maize seeds. For molecular study, activity of heat-resistant proteins, esterase, superoxide dismutase, catalase and α-amylase enzymes were assessed. Study of AOX1, ZmMPK5, SOD, APX, SAD, ENR and LEA genes with real time polymerase chain reaction (PCR) were carried out. AOX, SAD and LEA genes that are related as tolerant to abiotic stress showed higher expression in line 64, which was classified as tolerant to low germination temperature. The ZmMPK5 gene is associated with increased production of abscisic acid and expressed more in line 54, which was considered as susceptible to low germination temperature. Key words: Zea mays, seed vigor, abiotic stress.

RESUMO - Xenia e considerado o resultado do cruzamento pelo alopolen que se manifesta na geracao da planta mae. Neste trabalho, objetivou-se verificar a ocorrencia do efeito xenia na produtividade e na estrutura do endosperma de sementes de milho. O experimento foi conduzido em duas epocas de semeadura (25/11/2011 e 15/12/2011). No pri-meiro ensaio, foram produzidas as sementes a partir dos cruzamentos dos hibridos simples: DKB390pro X DKB177; DKB390pro X DKB175; DKB390pro X DKB175pro. O segundo ensaio foi conduzido a 100 m de distância do pri-meiro e foram produzidas as sementes a partir dos cruzamentos das linhagens: L30 X L91; L30 X L63. Sementes dos hibridos DKB177, DKB 175, DKB175pro e DKB390pro e das linhagens L63, L91 e L30 foram produzidas em campo isolado a 100 m de qualquer outro polinizador, constituindo os tratamentos testemunhas. Foram avaliados o peso de 100 sementes, a profundidade de sementes, a produtividade e a estrutura do endosperma de sementes de milho. Para o cruzamento DKB390pro X DKB175, foram observados os maiores acrescimos nos valores de peso de 100 sementes e produtividade final nas duas epocas de semeadura. O efeito xenia sobre a estrutura do endosperma de sementes de milho varia com o polinizador utilizado em cruzamentos. Palavras-chave: Zea mays L, cruzamentos, alopolen. XENIA ON MAIZE PRODUCTIVITY AND IN THE ENDOSPERM STRUCTURE OF MAIZE KERNELS ABSTRACT - Xenia effect is the result of crossing by allopollen which is manifested in the mother plant generation. This work aimed at verifying the Xenia effect in maize seed productivity and in the endosperm structure of maize seeds. Four single hybrids and three inbred lines with good agronomic characteristics were used. The experiment was conducted in two sowing dates (11/25/2011 and 12/15/2011). In the first trial, seeds were produced from the crossing between simple hybrids: DKB390pro X DKB177; DKB390pro X DKB175; DKB390pro X DKB175pro. The second trial was installed at 100 m from the first with the crossings between lines L30 X L91, L30 X L63. Seeds of the hybrids DKB177, DKB 175, DKB175 pro, DKB390pro and the inbred lines L63, L91 and L30 were produced in an isolated field at 100 m from any other pollinator, constituting the control treatments. Weight of 100 seeds, seed depth, productivity and endosperm structure of maize seeds were evaluated. The Xenia expression was observed in the DKB175pro maize seeds when pollinated by DKB390pro, increasing in 23.58% the weight of 100 seeds. For the DKB390pro X DKB175 crossing, with the DKB390pro as pollinator, the largest increments in the weight of 100 seeds value and in the final yield were observed on both sowing periods. The xenia effect on the endosperm structure of maize seeds varies with the pollinator used in the crossings. Key words: Zea mays L., crosses, allopollen.

RESUMO - No Brasil, com o uso constante de adubos concentrados em NPK com baixos teores de enxofre, alem de outros fatores, o Enxofre (S) passou a ser limitante ao desenvolvimento das plantas. Com o objetivo de avaliar a eficiencia agronomica de fertilizantes na cultura do milho associados a duas fontes de enxofre e a duas formas de micro-nutrientes, foram conduzidos dois experimentos sob plantio direto em novembro 2008. Um experimento foi semeado em Ijaci, MG e o outro em Lavras, MG. Os delineamentos experimentais foram de blocos casualizados com quatro repeticoes em esquema fatorial 3 x 2, sendo tres fertilizantes, um sem enxofre e os outros dois com diferentes fontes de enxofre (enxofre elementar ou sulfato de amonio), associados a duas formas de micronutrientes (granulado ou grânulo revestido). Nao foram constatadas diferencas para fontes de enxofre e para formas de fornecimento dos micronutrien-tes. As diferentes fontes de enxofre afetaram as caracteristicas estudadas de modo semelhante e independeram da forma usada dos micronutrientes. A substituicao do enxofre proveniente do sulfato de amonio pelo enxofre elementar em fertilizantes NPK ou ate mesmo a ausencia deste nos fertilizantes nao comprometeu a eficiencia dos fertilizantes avaliados pela produtividade. Palavra-chave: Zea mays, enxofre elementar, sulfato de amonio. EVALUATION OF SULFUR SOURCES AND FORMS OF MICRONUTRIENTS COATED ONTO NPK FERTILIZER IN MAIZE ABSTRACT- In Brazil, as a result of the constant use of concentrated NPK fertilizers, besides some other factors, sulfur became a limiting nutrient for plant development. Two experiments were performed under no till system in November 2008 aiming to evaluate the agronomic efficiency of fertilizers associated to two sulfur sources and two micronutrients forms in corn crops,. one in Ijaci-MG and one in Lavras-MG. The experimental design was randomized blocks with four replications in a 3 x 2 factorial scheme, with three fertilizers, one without sulfur and the other two with different sources of sulfur (elemental sulfur or ammonium sulfate), associated to two forms of micronutrients (granular or coated granule). No differences were observed for sulfur sources and forms of supplying micronutrients. The different sulfur sources affected the characteristics in a similar way and did not depend on the form of the micronutrients. The replacement of sulfur originated from ammonium sulfate by the elemental sulfur in NPK fertilizers or even the absence of this in fertilizers did not affect the efficiency of fertilizer evaluated by productivity. Keys words: Zea mays, elemental sulfur, ammonium sulfate.

RESUMO – Este trabalho objetivou avaliar o efeito da populacao de plantas e epoca de corte sobre a producao de sorgo sacarino. O experimento foi instalado em novembro de 2012, em Lavras–MG. O delineamento experimental foi o de blocos casualizados, com 3 repeticoes, em esquema fatorial 4x4 (4 populacoes: 70, 100, 130 e 160 mil plantas ha-1; 4 epocas de corte: 0 dias apos o florescimento (DAF), 10 DAF, 20 DAF e maturidade fisiologica aos 40 DAF. A partir da analise do caldo sacarino da cultivar BRS 506, foram avaliadas as caracteristicas industriais: volume de caldo (VC), solidos soluveis totais (obrix), acucares redutores totais (ART) e toneladas de brix por hectare (TBH). O aumento das populacoes propicia o maior VC e nao afetou as demais variaveis. As caracteristicas industriais sao influenciadas pelas epocas de corte. O brix e a ART apresentaram crescimento linear com o aumento do periodo apos o florescimento para o corte de plantas. A maior produtividade (VC e TBH) foi obtida proxima aos 17 e 14 DAF, respectivamente, favorecendo maior producao de etanol nesses estadios. Palavras-chaves: sorghum bicolor, brix, biocombustivel. EFFECT OF PLANT POPULATION AND HARVEST TIME ON SORGHUM SACCHARINE YIELD ABSTRACT- The present work aimed to evaluate the sorghum saccharine cultivar BRS 506 regarding industrial characteristics related to yield and production of ethanol related to plant population and harvest time. The experiment was carried out in November 2012, in Lavras – MG. A randomized blocks experimental design was used, with three replications, in a 4x4 factorial scheme [4 populations: 70, 100, 130 and 160 thousands plants per hectare; 4 cutting seasons according to flowering: 0 days after flowering (DAF), 10 DAF, 20 DAF and physiological maturity 40 DAF]. Industrial characteristics such as juice volume (JV), total soluble solid (0brix), total reducing sugars (TRS) and tones of brix per hectare (TBH) were evaluated after the analysis of saccharine juice of the BRS 506. Increased population provided higher JV. The industrial characteristics were affected by the period of cutting. The cutting at 40 DAF provided the highest 0brix and TRS. JV and TBH reached the highest values at 17 and 14 DAF, respectively, periods showing the highest production of ethanol. Key words: Sorghum bicolor, production of ethanol, brix, biofuel.

RESUMO – O sorgo sacarino e uma excelente opcao para a producao de etanol sob os pontos de vista agronomico e industrial. Possui alta producao de massa verde e colmos suculentos com acucares fermentaveis. O objetivo foi avaliar o sorgo sacarino quanto a caracteristicas industriais relacionadas a producao de etanol em funcao de epocas de semeadura na regiao de Lavras, MG. Foram instalados cinco experimentos em intervalos de 21 dias a partir de 01/11/2012, no CDTCA / UFLA, em Lavras, MG. O delineamento experimental foi blocos casualizados, em esquema de parcelas subdivididas, com cinco repeticoes. Para as cinco epocas de semeaduras, as parcelas foram formadas por duas populacoes de plantas (100 e 130 mil plantas ha-1) e as subparcelas por duas epocas de corte / colheita das plantas. Utilizou-se a variedade de sorgo sacarino BRS 506. As variaveis avaliadas na colheita foram: materia verde; volume de caldo; solidos soluveis totais (obrix); e toneladas de brix por hectare (TBH). As epocas de semeadura, as populacoes e as epocas de corte influenciaram o rendimento de materia verde, o volume de caldo e as TBH. A semeadura realizada em 22 de novembro na epoca de corte aos 20 DAF e na populacao de 130 mil plantas ha-1 proporcionou incremento na maioria das variaveis. Palavras-chave: Sorghum bicolor, producao de etanol, brix, biocombustiveis. EFFECTS OF PLANT POPULATION, SOWING DATE AND HARVEST TIME ON PRODUCTIVITY OF SACCHARINE SORGHUM BRS 506 ABSTRACT- Sweet sorghum is an excellent option under the agronomic and industrial points of view, presenting succulent stems with fermentable sugars and high green matter production. The objective of the present study was to evaluate saccharine sorghum regarding the industrial characteristics related to the production of ethanol and different periods of sowing in Lavras-MG region. Five experiments were done in intervals of 21 days, in the Centre for Technological and Scientific Development in Agriculture UFLA, Lavras-MG. A randomized blocks experimental design was used with five replications. The sweetness of juice of the variety BRS 506 was assessed in a Split-Plot design,, with two populations (100 and 130 thousands plants per hectares) and two different periods of cutting (20 and 40 DAF). At harvest the variables evaluated were: green matter, broth volume, total soluble solids (obrix) and tons of Brix per hectare (TBH). Sowing date, population and cutting season affected the yield of green matter, volume of broth and TBH. Sowing at 22 November, cutting at 20 DAF and population of 130,000 plants ha-1 caused increase in most characteristics. Key words: sorghum bicolor, production of ethanol, brix, biofuels.

It is known that genetic manipulation of plants can cause pleiotropic effects or mutations originated from the incorporation of an exogenous gene, which may interfere with foraging of herbivores. Little is known about how herbicide-tolerant plants (singular event), insect-resistant plants (singular event), and herbicide-tolerant plus insect-resistant plants (stacked event) affect foraging of Spodoptera frugiperda. The objective of this study was to evaluate if singular and stacked maize events interfere with the quantity and quality of S. frugiperda eggs. The hybrids DKB390 (VTPRO, VTPRO2, VTPRO3), DKB390 (isogenic) and Ag 3700 RR2 were evaluated. Choice and non-choice tests for oviposition preference of S. frugiperda, in plants with and without injuries, were performed in a greenhouse. The size of egg masses and the number of hatched larvae were evaluated. Larger egg masses and higher number of hatched larvae per plant were found in transgenic plants. The conclusion was that S. frugiperda females modify their oviposition behavior in the presence of transgenic and non-transgenic maize hybrids, especially when they are injured. However, the females do not discriminate between singular or stacked hybrid for oviposition.

Saccharine sorghum is an excellent option for ethanol production under industrial and agronomic perspectives, due to high green matter production and succulent stalks with fermentable sugars. The aim of this work was to evaluate the harvesting season and plants population effect over theethanol and fodder production from sweet sorghum culture BRS 506. The experiment was installed in November 2012, at (CDTCA/UFLA), located in Lavras (MG). The experimental design was in randomized blocks, with 3 repetitions, factorial scheme 4 x 4 (4 populations: 70, 100, 130 and 160thousand plants ha-1 ; 4 harvesting seasons: flowering (0 days after flowering (DAF), 10 DAF, 20 DAF and physiological maturity at 40 DAF). The variables evaluated at harvesting: green matter weight (GM), dry matter weight (DM), juice volume (JV), total soluble solids (ºbrix), total reducing sugars (TRS) and brix tonnes per hectare (TBH). The populations increase provided the highest JV and it has not affected other variables. The characteristics were influenced by the harvesting seasons. The harvesting season at 40 DAF provided the highest ºbrix. The ºbrix and the TRS showed linear growth with an increase after flowering for plants harvesting. The highest productivities (GM, DM, JV and TBH) were obtained close to 17, 22, 17 and 14 DAF, respectively, favoring higher fodder and ethanolproduction in these stages.

This study evaluated the effect of water and salt stresses on the physiological quality and on the electrophoresis patterns of heat resistant proteins in corn seeds. The experiments were carried out in the laboratories of seed analysis and biotechnology at the Universidade Federal de Lavras. Corn seeds of the hybrid GNZ 2004 and the inbred line LE 57 were used. The seeds were produced in soils with an electric conductivity of 3 dS m-1 (under stress) and 0.4 dS m-1 (without stress) and in pots containing substrate with a water holding capacity of 40% (with stress) and 70% (without stress). The randomized complete block design with treatments arranged in a split-plot scheme was used with four replications . Seeds were harvested at different stages of development. Seed physiological quality was evaluated using the tests of germination, artificial aging and cold test. The patterns of heat resistant proteins were evaluated by electrophoresis. The results showed that depending on seed developmental stage there was an effect of water and salt stresses on the seed vigor. The electrophoretical patterns of heat resistant proteins were stable in seeds produced under different stress conditions. Key words: Zea mays, developmental stages, late embryogenesis abundant proteins (LEA proteins).

O objetivo deste trabalho foi verificar a relacao entre a perda de agua dos graos com as caracteristicas produtividade de graos e ciclo de hibridos de milho. Para isso, na safra agricola 2008/2009, sob o sistema de plantio direto foram conduzidos experimentos nos municipios de Lavras e Ingai, ambos localizados na regiao Sul de Minas Gerais. Em ambos os locais foram instalados dois experimentos em duas epocas de semeadura, sendo uma na primeira quinzena de novembro e a outra na primeira quinzena de dezembro. O delineamento experimental utilizado foi o de blocos casualizados com tres repeticoes e avaliados 14 hibridos. As caracteristicas avaliadas foram a produtividade de graos, numero de dias e o somatorio de graus dia ate o florescimento pleno, somatorio de graus dia ate os pontos de maturidade fisiologica e de colheita, bem como o teor de agua dos graus. Constatou-se que nas condicoes estudadas, que a perda de agua dos graos nao esta associada com as caracteristicas produtividade de graos e ciclo de hibridos de milho.

Transgene insert location in the genome through different methods is random. Thus, alterations in the expression of desired trait may occur, as well as alterations in the expression of other characteristics of receptor plant. The purpose of this study was to compare Bt transgenic maize hybrids and the respective conventional isogenic hybrid in relation to adaptability and phenotypic stability. Field trails were set up in four locations of Minas Gerais, Brazil (Campo do Meio, Lavras, Madre de Deus and Paraguacu). A randomized complete block design was used, with three replications, and the treatment structure was a factorial 6 × 2, with six hybrids in the transgenic and conventional versions. Plant and ear height and grain yield were evaluated. To estimate stability, the Anicchiarico, Wricke and AMMI methodologies were used. Grain yield and ear height of the transgenic hybrids and their respective conventional isogenic hybrid did not differ. There are differences in the phenotypic stability between transgenic hybrids with Bt technology and their counterpart conventional isogenic hybrid.

The aim of this study was to perform genome-wide selection using a set of Dart-seq markers associated to the additive-dominant genomic best linear unbiased prediction (GBLUP) model to predict maize grain yield in different crop seasons and locations. Genotyping was performed with Dart-seq markers from 447 lines coming from a germplasm bank of a private maize breeding company. Crossing these lines provided 838 single-cross hybrids evaluated in six locations in the winter crop season of 2013 and 797 single-cross hybrids evaluated in four locations in the summer crop season of 2013/2014. Four k-fold levels were applied on the full panel of 23,153 Dart genotyping-by-sequencing markers and samples of 50% of the available markers. The different crop seasons were used as training and validation populations to estimate the predictive accuracy. The magnitude of the correlations between predicted and observed hybrids ranged from 0.82 to 0.89 in the winter crop season and from 0.56 to 0.76 in the summer crop season. The correlations between combinations tested in different crop seasons and locations were encouraging (0.53). Predictive ability was highly influenced by the genetic background and also by the interaction between crop seasons. The coincidences between the genomic values of the summer crop and winter crop, in terms of discard, were 89 and 90%. This result shows the possibility of using genomic prediction in breeding programs for initial discard of low-yielding genotypes. The GBLUP method was able to generate high correlations between predicted and observed hybrids, even at high levels of missing in k-fold and in different locations and crop seasons.

In recent years, there has been a large incidence of fungi causing “ear rot” in maize in Brazil, the main fungus being Fusarium verticillioides. The most efficient and competitive alternative for control of this disease consists of using maize hybrids resistant to this pathogen. Thus, the aims of this study were to analyze the genetic variability of maize inbred lines in regard to resistance to ear rot to observe if there is a maternal effect to resistance to ear rot, to study genetic control of the traits evaluated in hybrids originating from inbred lines of the maize breeding program at the Agriculture Department of Universidade Federal de Lavras (Lavras, MG, Brazil), and characterize the gene expression pattern related to the plant defense mechanism against F. verticillioides. High genetic availability was observed for resistance to this disease among the inbred lines evaluated. Considering combined diallel analysis, it was observed that the mean square of general combining ability (GCA) was not significant for the characteristic under study. However, specific combining ability (SCA) was significant, which indicates the predominance of non-additive effects involved in control of the characteristic for the population evaluated. A maternal effect was not observed for the characteristic of ear rot resistance in this study. Inbred lines 22, 58, and 91 showed potential for use in breeding programs aiming at resistance to F. verticillioides. Only two genes, LOX8 and Hsp82, had a satisfactory result that was able to be related to a plant defense mechanism when there is ear rot infection, though expression of these genes was observed in only one susceptible genotype. Thus, the genes LOX8 and Hsp82 are potential molecular markers for selection of maize inbred lines resistant to F. verticillioides.

The aim of this study was to use a multi-environment trial approach from a mixed model point of view for factor analysis (FA) of the stability and adaptability of hybrids. Twenty-eight hybrids were analyzed in 35 environments across four seasons/years (summer season 2010, winter season 2011, summer season 2011 and winter season 2012). Several of these hybrids were analyzed during the first seasons and were not evaluated in later seasons or vice versa. Therefore, the dataset used in this study simulated the dynamics of a genetic breeding program with removal and inclusion of genotypes over the years. A biplot of the factor scores and loadings showed that the environments were more similar within seasons than between seasons, thereby suggesting that a given site may behave differently year after year. The season was more effective in discovery mega-environments. The FA models may be directly interpreted as GGE biplot analysis since the first factor score had a perfect fit ( $$r^{2} = 0.99$$ ) with the empirical best linear unbiased predictors of the genotypes. Given the assumption of normality for the factor scores, confidence ellipses could be created to directly compare the genotypes in the biplot. Stability and adaptability could be analyzed in unbalanced experiments with the removal and inclusion of genotypes over time. This approach allowed certain trends in a breeding program to be measured by directly comparing hybrids developed for the first or winter season. The biplot interpretation was direct and intuitive, and it has the same properties as the GGE biplot obtained by singular value decomposition.

O desenvolvimento de cultivares adaptadas a estresse de nitrogenio (N) e uma das opcoes de sustentabilidade ecologica para aumentar a produtividade em sistemas agricolas de baixa e tambem alta tecnologia. O objetivo com este trabalho foi avaliar a eficiencia e uso de N (EUN) em populacoes tropicais de milho ( Zea mays L. ) para a producao forrageira no Sul do Estado do Tocantins. Dois experimentos foram instalados em novembro de 2009, um com baixa disponibilidade de N e outro com alta disponibilidade de N. Vinte e quatro populacoes e uma cultivar comercial foram usadas nos experimentos. O delineamento experimental utilizado foi blocos casualizados com duas repeticoes. Foram avaliadas a altura de plantas e espiga, a participacao da espiga na massa total da planta, massa verde da planta com e sem espiga, massa verde total e EUN na producao de forragem. Pelo metodo de Moll, foram observadas diferencas entre populacoes para a EUN, porem essas diferencas nao foram observadas pela metodologia de Fischer. As populacoes 12-4, 1-3, 12-6, 12-5, 26-1, 15-2, 25-2 e 1-5 sao consideradas eficientes no uso de N. As populacoes 12-6, 12-5, 12-4, 1-3, 1-4, 1-5 e 15-2 sao as melhores para uso em ambientes de alto e baixo N, combinando uma satisfatoria producao de massa verde e sendo eficiente no uso de N.

This paper proposes an alternative method for evaluating the stability and adaptability of maize hybrids using a genotype-ideotype distance index (GIDI) for selection. Data from seven variables were used, obtained through evaluation of 25 maize hybrids at six sites in southern Brazil. The GIDI was estimated by means of the generalized Mahalanobis distance for each plot of the test. We then proceeded to GGE biplot analysis in order to compare the predictive accuracy of the GGE models and the grouping of environments and to select the best five hybrids. The G × E interaction was significant for both variables assessed. The GGE model with two principal components obtained a predictive accuracy (PRECORR) of 0.8913 for the GIDI and 0.8709 for yield (t ha−1). Two groups of environments were obtained upon analyzing the GIDI, whereas all the environments remained in the same group upon analyzing yield. Coincidence occurred in only two hybrids considering evaluation of the two features. The GIDI assessment provided for selection of hybrids that combine adaptability and stability in most of the variables assessed, making its use more highly recommended than analyzing each variable separately. Not all the higher-yielding hybrids were the best in the other variables assessed.

Early characterization of genotypes, through the previous assessment of physiological quality of their seeds and their enzymatic systems, can provide parameters capable of aiding in the selection of new maize cultivars tolerant to water stress. Thus, this study was aimed at assessing seed performance of five different maize lines subjected to four different water stress levels. The physiological quality of seeds germinated under the osmotic potentials of 0.0, -0.3, -0.6 and -0.9 MPa was assessed by germination test, number of strong normal seedlings and T50, as well as by the expression of the isozymes superoxide dismutase (SOD), catalase (CAT), glutamate oxaloacetate transaminase (GOT), esterase (EST), malate dehydrogenase (MDH), alcohol dehydrogenase (ADH), and of heat-resistant proteins. The osmotic potential of -0.9 MPa affected the physiological quality and vigor of seeds of all maize lines assessed. The highest values for the germination percent, in the lowest osmotic potentials assessed, were found in the seeds of line 63. However, seeds of line 91 were superior in regard to vigor. Increased expression of the enzymes SOD and CAT, considered as enzymes of the antioxidant system, was observed in seeds of lines 44 and 91. Thus, line 91 was considered as promising for tolerance to water stress. A caracterização precoce de genótipos, por meio de avaliação prévia da qualidade fisiológica de suas sementes e seus sistemas enzimáticos, pode fornecer parâmetros capazes de auxiliar na seleção de novas cultivares de milho tolerantes ao estresse hídrico. Assim, o objetivo deste estudo foi avaliar o desempenho das sementes de cinco linhagens de milho submetidas à quatro níveis de estresse hídrico. Para isso, a qualidade fisiológica das sementes, germinadas sob os potenciais osmóticos de 0,0; -0,3; -0,6 e -0,9 MPa, foi avaliada pelo teste de germinação, número de plântulas normais fortes e T50, bem como pela expressão das isoenzimas superóxido dismutase (SOD), catalase (CAT), glutamato oxalacetato transaminase (GOT), esterase (EST), malato desidrogenase (MDH), álcool desidrogenase (ADH) e de proteínas resistentes ao calor. O potencial osmótico de -0,9 MPa afetou a qualidade fisiológica, bem como o vigor das sementes de todas as linhagens avaliadas. Os maiores valores para a porcentagem de germinação, nos menores potenciais osmóticos avaliados, foram observados nas sementes da linhagem 63. No entanto, sementes da linhagem 91 foram superiores quanto ao vigor. Maior expressão das enzimas SOD e CAT, consideradas como enzimas do sistema antioxidante, foram observadas em sementes das linhagens 44 e 91. Assim, a linhagem 91 é considerada como linhagem promissora quanto à tolerância ao estresse hídrico.

This study seeks to quantify the importance of epistatic effects on the heterosis of maize using complex pedigrees in a single model of the so-called bi-, tri-, and tetra-alleles in an analysis with and without information from microsatellite markers. To this end, 51 inbred lines were sampled from different backgrounds, obtaining 6 double cross hybrids, 14 triple cross hybrids, and 58 single cross hybrids, for a total of 78 hybrids. Seventy-nine microsatellite markers were used in the genotyping of the 51 lines. These markers were distributed throughout the 10 linkage groups in maize. This information was used to construct an information matrix on kinship. The mixed models and restricted maximum likelihood approaches were used to estimate additive, dominant and epistatic effects. It was observed that the dominant by dominant epistasis was the most important effect related to genetic control of the heterosis in maize. Also, our study demonstrated that it is possible to exploit a large amount of information when we jointly analyze simple, double, and three-way cross hybrids under the same model. Using this approach, it is possible to dissect heterosis into several components and to adopt the best crossbreeding strategy based on the importance of each component. Additionally, it was possible to verify that the use of molecular markers improves the accuracy of calculating the epistatic and dominance effects. Thus, using the current state-of-art in quantitative genetics and statistical methods the concept of crossbreeding can be expanded to frontiers that are far beyond the traditional general and specific combining ability.

Este trabalho foi realizado com o objetivo de avaliar os efeitos da aplicação de fungicida, no controle da Cercosporiose e da Mancha-Branca do milho, e suas consequências na produtividade de grãos e na incidência de grãos ardidos, além de estabelecer a relação existente entre a produtividade de grãos e a severidade dessas doenças. Dois experimentos distintos (com Azoxystrobina + Cyproconazole e tratamento controle) foram conduzidos em três locais, no ano agrícola de 2007/2008. Utilizaram-se 12 híbridos comerciais de milho, que foram avaliados em delineamento de blocos casualizados, com três repetições. Foram realizadas cinco avaliações da severidade das doenças Cercosporiose e Mancha-Branca, por meio de escala de notas, variando de 1 (altamente resistente) a 9 (altamente susceptível). Estimou-se a área abaixo da curva de progresso da doença (AACPD). A aplicação de fungicida é eficiente no controle de doenças foliares e na redução da incidência de grãos ardidos, além de proporcionar 12% de aumento na produtividade de grãos, em relação à do tratamento controle. As doenças foliares Cercosporiose e Mancha-Branca reduzem a produtividade de grãos de milho e essa redução é maior quando as doenças ocorrem mais precocemente. A Cercosporiose provoca maior redução na produtividade de grãos, quando comparada com a Mancha-Branca.

The physiological quality of maize seeds is affected by the genotype. Thus, the study of expression of genes associated with this characteristic is important in the genotype selection process in breeding programs. The aim of this research was to study the expression of amylase enzymes associated with physiological quality of maize seeds with different genotypes and seed sizes. We further sought to assess the expression of these enzymes in dry and soaked seeds The experiment was conducted in the experimental area and the Central Seed Laboratory of the Department of Agriculture of the Universidade Federal de Lavras. Seeds of four maize inbred lines were used, classified in two sizes. The physiological quality of the seeds was evaluated by means of germination, seedling emergence, seedling emergence speed index and accelerated aging test. Expression of the alpha amylase enzyme was evaluated by the electrophoresis technique and expression of the alpha amylase B73, alpha amylase (LOC542522) and beta amylase 5 (amyb5) genes was studied by the qRT-PCR technique in dry and soaked seeds of the inbred lines. There is differentiated expression of amylase enzymes in maize seeds of inbred lines with different levels of physiological quality. higher expression of amylase enzymes is observed in soaked maize seeds. The expression of transcripts is higher in smaller as wellas in soaked maize seeds of inbred lines.

The aim of this study was to identify inbred progenies of S0:1 maize (Zea mays L.) plants that were efficient at a low level of technology and responsive at a high level of technology through the use of topcrosses. Two contrasting environments were created using two levels of base fertilization and topdressing, so that the levels of nitrogen, phosphorus, and potassium were applied four times higher in one environment than in the other. We used S0:1 progenies derived from commercial hybrids in topcrosses with two testers (an elite line from the flint heterotic group and an elite line from the dent heterotic group). The progenies and three controls were evaluated in an augmented block design in Nossa Senhora das Dores, SE, Brazil in the 2010 crop season. The average grain yield in the high-technological level was 21.44% greater than that in the low-technological level. There were no changes in progeny behavior in the two technological levels for grain yield. The testers did not differ in the average grain yield of the progenies at the two technological levels. Therefore, it is possible to select progenies derived from commercial hybrids that have an efficient response to fertilization.

The objectives of this study were to evaluate corn cultivars for efficiency in the absorption and use of nitrogen (N) levels of efficiency through the use of nitrogen in contrasting levels of this nutrient in the greenhouse. The experiment was carried out in a greenhouse and the experimental design was in randomized blocks, with 20 treatments and four replicates, in a 10 x 2 factorial arrangement. All 10 maize cultivars were represented by local varieties and commercial hybrids, and the applied N levels were 100 and 400 mg dm-3. Plots were represented by 8L pots containing 4 plants each, which were harvested in phenological stage V8. The evaluated characteristics were dry matter weight and N level of shoot and roots. The nutritional efficiency of cultivars was also evaluated. The studied cultivars had distinct characteristics concerning N use and absorption efficiency in environments of high and low nitrogen levels. The contrasting N levels allowed the occurrence of differences needed to distinguish the most efficient cultivars. Genotypes efficient for N use and responsive to its application can be selected based on the indexes used in this work.

The objectives of this study were to evaluate corn cultivars for efficiency in the absorption and use of nitrogen (N) levels of efficiency through the use of nitrogen in contrasting levels of this nutrient in the greenhouse. The experiment was carried out in a greenhouse and the experimental design was in randomized blocks, with 20 treatments and four replicates, in a 10 x 2 factorial arrangement. All 10 maize cultivars were represented by local varieties and commercial hybrids, and the applied N levels were 100 and 400 mg dm-3. Plots were represented by 8L pots containing 4 plants each, which were harvested in phenological stage V8. The evaluated characteristics were dry matter weight and N level of shoot and roots. The nutritional efficiency of cultivars was also evaluated. The studied cultivars had distinct characteristics concerning N use and absorption efficiency in environments of high and low nitrogen levels. The contrasting N levels allowed the occurrence of differences needed to distinguish the most efficient cultivars. Genotypes efficient for N use and responsive to its application can be selected based on the indexes used in this work. Os objetivos deste trabalho foram avaliar cultivares de milho quanto à eficiência na absorção e uso de nitrogênio (N) através de índices de eficiência de utilização de nitrogênio, em níveis contrastantes desse nutriente em ambiente de casa de vegetação. O experimento foi conduzido em casa de vegetação e o delineamento experimental utilizado foi o de blocos casualizados, com 20 tratamentos e quatro repetições, dispostos em um esquema fatorial de 10 x 2. As 10 cultivares de milho foram representadas por variedades locais e híbridos comerciais e as doses de N aplicadas foram de 100 e 400 mg dm-3. As parcelas foram representadas por vasos de 8 L, os quais continham 4 plantas por vaso, sendo colhidas no estádio fenológico V8. As características avaliadas foram o peso de matéria seca e teor de N da parte aérea e raízes. Também foi avaliada a eficiência nutricional das cultivares. As cultivares estudadas apresentaram características distintas quanto à eficiência no uso e absorção de N nos ambientes com alto e baixo nível de nitrogênio. Os níveis contrastantes de N utilizados permitiram que ocorressem diferenças necessárias para distinguir as cultivares mais eficientes. Genótipos eficientes para uso de N e responsivos a sua aplicação podem ser selecionados pelos índices utilizados nesse trabalho.

The analysis of multiples traits has been largely employed in animal and forestry crop breeding; however, in annual crops such as common bean this approach is practically lacking. This study examined the selective accuracy and estimates of genetic parameters in common bean using single- and multi-trait analyses in several designs of genetic correlations and heritabilities by means of simulated- and real-traits. We also compared the efficiency of the Bayesian and REML methods as regarding its selective accuracy and estimates of genetic parameters. In real data experiments, 100 endogamic families of common bean were assessed for grain yield (GY) and grain type (GT) in three environments using a 10 × 10 triple lattice design. Single- and multi-trait analyses were applied for these traits using REML-based BLUP analysis and Bayesian methods. In simulated experiments, traits corresponding to GY and yield components in common bean were simulated under several levels of genetic correlations and evaluated under different levels of heritability in order to verify in which genetic/experimental design it is advantageous to apply single- or multi-trait analyses. The results obtained in this study indicated that GY and GT present low genetic correlation and, therefore, multi-trait analysis may be unjustifiable for these traits. The Bayesian and REML multi-trait analyses were equivalent in point and interval estimates of genetic parameters and predictive accuracy, both for the field and simulated experiments. In addition, it was found that multi-trait analysis is justified in situations where the traits present low/moderate heritability and medium/high genetic correlations among them. It also was found that GY in common bean may be outstandingly favored in accuracy when evaluated jointly with its components. Thus, one can conclude that the simultaneous analysis of GY and yield components in common bean may provide superior gains accuracy and selection efficiency, being the response to selection better obtained by use of the multi-trait heritability.

O objetivo deste trabalho foi estimar o fluxo gênico em milho transgênico com resistência a insetos, em lavouras comerciais. Amostras de grãos foram coletadas em lavouras com milho convencional e transgênico, nos municípios de: Itumirim, Uberlândia, Paracatu e Tupaciguara, MG; Itapetininga e Pedrinhas, SP; e Assaí e Ponta Grossa, PR. As amostras foram coletadas em lavouras de milho convencional, a partir de 5 m de distância da fonte com o milho transgênico. Foram coletadas dez espigas de plantas individuais por ponto, em quatro repetições, no total de 40 espigas para cada distância amostrada. As análises de fluxo gênico foram realizadas por meio da técnica de reação em cadeia da polimerase (PCR) em tempo real. Em média, 82% da fecundação cruzada ocorreu nos primeiros 30 m. Em Itapetininga, SP, foram observadas as maiores taxas de fecundação cruzada - acima de 10% até a distância de 50 m -, porém, inferiores a 1% na distância de 100 m. O isolamento de 20 m, com dez linhas de bordadura, não é suficiente para garantir taxas de fecundação cruzada inferiores a 1%. The objective of this work was to estimate the gene flow on insect-resistant transgenic maize in grain production fields. Grain samples were collected in fields containing conventional and transgenic maize in the Brazilian municipalities of: Itumirim, Uberlândia, Paracatu, and Tupaciguara, in the state of Minas Gerais; Itapetininga and Pedrinhas, in the state of São Paulo; and Assaí and Ponta-Grossa, in the state of Paraná. Seed samples were collected in conventional maize crops starting 5 m away from the transgenic maize source. Ten corn cobs were collected from individual plants per sampling point, with four replicates, totaling 40 corn cobs at each evaluated distance. Gene flow analyses were carried out by real-time polymerase chain reaction (PCR). On average, 82% of cross-fertilization occurred within the first 30 m. The highest outcrossing rates were observed in Itapetininga, SP, - at rates above 10% up to a distance of 50 m; however, less than 1% at 100 m distance. The 20-m isolation, with ten border lines, is not sufficient to ensure outcrossing rates lower than 1%.

The objective of this experiment was to characterize the dry matter production of vegetative components (stalk, leaf, husk, and cob) and reproductive components (grain) of the corn plant according to planting time and the grain maturity stage. Eight corn hybrids with different agronomic characteristics were used to carry out the experiments. Two experiments were performed with planting undertaken on 11/11/2007 and 12/12/2007 under a conventional tillage system. The eight corn cultivars were harvested at three grain maturity stages, half milk line, three quarters milk line and black layer. An 8 × 3 factorial (eight hybrids and the three cutting times) randomized blocks design was used, with three replications. Individual analysis of variance was performed for each experiment. Then joint analysis of variance was performed involving the two planting times. The means were grouped and the hybrids used as replications to characterize the components. Delay in planting significantly reduced the dry matter productivity of the whole plant; however, it did not reduce its degradability. The greatest dry matter productivity obtained was that of grain, followed by stalk, leaf, husk and cob. The vegetative components, leaves and husk, lose quality with delay in planting. The leaf is the vegetative component of highest quality, while the cob is the worst. Delay in planting increases the neutral detergent fiber content of the stalk, husk and cob.

O objetivo deste trabalho foi avaliar os efeitos da aplicacao de fungicida no controle da Cercosporiose e Mancha-Branca do milho e suas implicacoes na produtividade de graos e na incidencia de graos ardidos, alem de estabelecer a relacao existente entre a produtividade de graos e a severidade dessas doencas. Dois experimentos distintos (com Azoxystrobina + Cyproconazole e tratamento controle) foram conduzidos dentro de tres locais no ano agricola de 2007/2008. Utilizou-se 12 hibridos comerciais de milho que foram avaliados em delineamento de blocos casualizados, com tres repeticoes. Foram realizadas cinco avaliacoes da severidade das doencas Cercosporiose e Mancha-Branca, por meio de escala de notas variando de 1 (altamente resistente) a 9 (altamente suscetivel). A aplicacao de fungicida e eficiente no controle de doencas foliares e reducao da incidencia de graos ardidos alem de proporcionar 12% de aumento na produtividade de graos em relacao ao tratamento controle. As doencas foliares Cercosporiose e Mancha-Branca reduzem a produtividade de graos de milho e essa reducao e maior quando as doencas ocorrem mais precocemente. A Cercosporiose provoca maior reducao na produtividade de graos, quando comparada com a Mancha-Branca.

Pleiotropy has played an important role in understanding quantitative traits. However, the extensiveness of this effect in the genome and its consequences for plant improvement have not been fully elucidated. The aim of this study was to identify pleiotropic quantitative trait loci (QTLs) in maize using Bayesian multiple interval mapping. Additionally, we sought to obtain a better understanding of the inheritance, extent and distribution of pleiotropic effects of several components in maize production. The design III procedure was used from a population derived from the cross of the inbred lines L-14-04B and L-08-05F. Two hundred and fifty plants were genotyped with 177 microsatellite markers and backcrossed to both parents giving rise to 500 backcrossed progenies, which were evaluated in six environments for grain yield and its components. The results of this study suggest that mapping isolated traits limits our understanding of the genetic architecture of quantitative traits. This architecture can be better understood by using pleiotropic networks that facilitate the visualization of the complexity of quantitative inheritance, and this characterization will help to develop new selection strategies. It was also possible to confront the idea that it is feasible to identify QTLs for complex traits such as grain yield, as pleiotropy acts prominently on its subtraits and as this "trait" can be broken down and predicted almost completely by the QTLs of its components. Additionally, pleiotropic QTLs do not necessarily signify pleiotropy of allelic interactions, and this indicates that the pervasive pleiotropy does not limit the genetic adaptability of plants.

As sementes de milho doce apresentam altos teores de acucares soluveis e baixos teores de amido. Essas caracteristicas podem causar rapida perda de viabilidade das sementes durante o armazenamento. O objetivo deste trabalho foi avaliar a qualidade fisiologica de sementes de milho doce armazenadas em diferentes condicoes. Foram utilizadas sementes da cultivar SWB585, de formato redondo. As sementes foram embebidas em agua destilada com acido giberelico, nas concentracoes de 0, 10 e 20 mg.l -1 . Posteriormente a secagem, foram acondicionadas em embalagens de plastico, a vacuo, e em embalagens de papel, logo armazenadas em dois ambientes (câmara fria e temperatura ambiente), durante cinco periodos de armazenamento (0, 60, 120, 180 e 240 dias). Foram realizados os testes de germinacao, teste de frio, envelhecimento acelerado e indice de velocidade de emergencia. O experimento foi conduzido em delineamento inteiramente ao acaso, em esquema fatorial 2 x 2 x 3 x 5 (dois tipos de embalagens, dois ambientes, tres doses de GA3 e cinco periodos de armazenamento), com quatro repeticoes. Constatou-se que as embalagens nao influenciaram a qualidade fisiologica. O acido giberelico perde efeito sobre o desempenho das sementes com o decorrer do tempo de armazenamento. O vigor das sementes de milho doce diminui linearmente com o decorrer do tempo de armazenamento.

The objective of this study was to evaluate the effects of stalk/leaf ratio and the stage of maturity on the digestibility of the corn plant. Hybrids AG1051, AG4051, AG5011, DOW2B710, DOW2C577, DOW2A525, NB7315 and P30F90 were used, harvested at the one-half milk line (½ ML), three-quarters milk line (¾ ML) and black layer (BL) stages. A randomized block design was used in an 8 (hybrids) × 3 (stages of maturity) factorial design, with three replications. The means generated were used for grouping into high and low stalk/leaf ratio and a new analysis of variance was generated in a 2 × 3 (two groups and three stages of maturity) factorial design. The whole plant and its stalk, leaf, husk, cob and grain components were incubated in situ in the rumen of three cows for determination of degradability of dry matter and degradable neutral detergent fiber. Stalk/leaf ratio did not influence neutral detergent fiber content or the degradability of dry matter and neutral detergent fiber of any of the components, except for the cob, in which the high ratio group had greater degradable neutral detergent fiber contents. There was a reduction in the degradability of all the parts, except for the stalk and cob, and an increase in the neutral detergent fiber contents of the vegetative parts, except for the stalk. Unlike the vegetative components, the neutral detergent fiber contents of the whole plant decreased throughout the stages evaluated. For degradable neutral detergent fiber, there was a reduction in the whole plant and in its components. The advance of maturity reduces the quality of the vegetative components; however, this loss in the entire plant is moderated by grain filling. Forage quality depends more on the quality of the components than on their proportions in the dry matter.

O objetivo deste trabalho foi avaliar a correlacao e a influencia das caracteristicas qualitativas dos componentes da planta de milho na qualidade da forragem de hibridos de alta e baixa degradabilidade da materia seca da forragem. Oito cultivares de milho foram colhidas em tres estadios de maturacao dos graos, meia linha de leite (½ LL), tres quartos da linha de leite (¾ LL) e camada negra (CN). Utilizou-se o delineamento em blocos casualizados, em esquema fatorial oito (hibridos) x tres (epocas de corte) x duas (epocas de semeadura), com tres repeticoes. Neste trabalho, ficou evidente a importância da qualidade dos componentes vegetativos, pois o grupo de melhor qualidade da forragem apresentou qualidade superior em todos os componentes estudados. A degradabilidade dos componentes vegetativos tem correlacao maior com a degradabilidade da materia seca da planta inteira do que a degradabilidade e densidade de grao. O avanco na maturidade afeta a degradabilidade (DEG), fibra em detergente neutro (FDN) e a fibra em detergente neutro degradavel (FDND) da planta inteira e seus componentes, exceto para FDN degradavel de colmo.

O nitrogenio (N) e o nutriente que mais interfere na produtividade do milho. O desenvolvimento de cultivares eficientes no uso de N e uma estrategia eficaz para reduzir custos de producao e minimizar a dependencia de insumos agricolas. Os objetivos deste trabalho foram avaliar cultivares de milho quanto a eficiencia de absorcao e uso de N, em niveis contrastantes desse nutriente. O experimento foi conduzido em area experimental da Universidade Federal de Lavras (UFLA), em Lavras, MG, Brasil, no ano agricola 2006/07. O delineamento experimental utilizado foi em blocos casualizados, com 20 tratamentos e tres repeticoes, dispostos em um esquema fatorial com 10 cultivares e duas doses de N. Foram avaliados a produtividade de graos, massa seca e teores de N nos graos e na parte aerea. Tambem foram estimados os indices de eficiencia nutricional das cultivares. As cultivares de milho apresentaram desempenhos distintos quanto a eficiencia no uso e absorcao de nitrogenio. Os niveis contrastantes de nitrogenio permitiram que ocorressem as diferencas necessarias, entre as caracteristicas estudadas, para a selecao das cultivares mais eficientes. Os hibridos GNZ 2004 e P 30F53 destacaram-se por apresentarem os melhores desempenhos para os parâmetros de eficiencia utilizados.

The objective of this experiment was to evaluate the production of structural components and theirproportion in a whole maize plant dry matter harvested at different maturity stages. The commercial hybrids AG 1051,AG 4051, AG 5011, DOW 2B710, DOW 2C577, DOW 2A525, NB 7315 and P 30F90 were used. Harvests weredone at three maturity stages: half of milk line (½ ML), three quarters of milk line (¾ ML) and black layer (BL). Theexperiment was sown in Lavras, MG, Brazil at 2007/2008 crop season. The experimental design was a randomizedblock with three replicates, in an 8 x 3 factorial scheme. The participation of vegetative portion decreased with thedelay in harvest, except to cob. The grain component increased its yield and proportion in dry matter, being themain component that contributed to increase of the whole plant dry matter yield. The higher yield and proportion indecreasing order were grains, stalks, leaves, straws, and cobs. The leaves presented the largest contribution to the grainfilling. The change in the relations among fractions over maturity stages can be one of the causes of forage quality loss.

O Brasil é um dos maiores produtores de milho do mundo e possui grande potencial para a produção de milho verde. Além de agregar valor ao produto, a comercialização de milho verde cresceu muito nos últimos anos. Há escassez de informações sobre a avaliação e a obtenção de cultivares destinadas à produção de milho-verde e também sobre estudos genéticos das características envolvidas nessa produção. Objetivou-se, neste trabalho, estimar parâmetros genéticos e fenotípicos, a correlação genética, classificar e identificar híbridos de milho verde promissores ao mercado consumidor e avaliar a eficiência dos pesos econômicos atribuídos. Os resultados determinaram que a seleção terá sucesso, para as diferentes características de milho-verde, pois, a herdabilidade foi de alta magnitude para as características avaliadas. A avaliação da produtividade de espigas empalhadas (PEE) é suficiente para definir quais os híbridos apresentam o melhor desempenho para a produtividade de espigas comerciais (PEC), diâmetro (DIAM) e comprimento de espigas (COMP). Isso indica que as características PEC, DIAM e COMP podem ser descartadas da avaliação em programas de melhoramento de milho-verde. Os híbridos HS48, HS27, HS24, HS25, HS12 e HS45 acumularam um maior número de características desejadas em um único genótipo, com base no índice de seleção baseado na soma de postos, sendo os mais promissores para a produção de milho-verde. Os pesos econômicos utilizados foram capazes de distinguir e identificar os híbridos mais promissores para a produção de milho- verde e podem ser utilizados como critério de seleção em programas de melhoramento de milho-verde. Brazil is one of the largest producers of corn of the world and it possesses great potential for vegetable corn production. Besides adding value to the product, the commercialization of vegetable corn increased in the last years. There is shortage of information about the evaluation and the acquisition of genotypes destined to the production of vegetable corn and also on genetic studies of the traits involved in this production. The objective of this work was to estimate the genetic and phenotypic parameters, and the genetic correlation, and to classify and identify hybrids of promising vegetable corn to the consumer market and to evaluate the efficiency of the attributed economical weights. The results determined that the selection will succeed, for the different traits of vegetable corn, because the heritability was of high magnitude to the appraised traits. Evaluation of husked ears yield (PEE) was enough to define which hybrid presents better commercial ear productivity, diameter and corn ear length. This indicates that those traits could be discarded in the selection process of genotypes of breeding programs for vegetable corn production. The hybrids HS48, HS27, HS24, HS25 and HS12 accumulated the largest number of desirable traits in a single genotype based on the sum of rank index. The used economical weights were efficient to distinguish and identify the most promising hybrid for vegetable corn production and they can be used as a selection criterion in programs of breeding of vegetable corn.

A composição química das sementes pode ser influenciada por fatores genéticos, ambientais e pela disponibilidade de nutrientes no solo durante a produção e, como consequência, terem o seu vigor afetado. O potássio pode influenciar a atividade de várias enzimas presentes nas plantas, necessárias em várias reações envolvidas na utilização de energia, síntese de amido, metabolismo do nitrogênio e respiração. Avaliou-se o efeito da adubação potássica e da calagem na composição química, qualidade fisiológica e na atividade de enzimas de sementes de soja. A pesquisa foi desenvolvida nos laboratórios de análises e biotecnologia de sementes do Departamento de Agricultura e no Laboratório de Produção Vegetal do Departamento de Ciências dos Alimentos da Universidade Federal de Lavras (UFLA). Em sementes de soja do cultivar Msoy 8001, produzidas sob 2 níveis de saturação por base (48% e 85%) e quatro doses de K2O por hectare (0, 50, 100 e 200 kg), foram avaliados teores de óleo e proteína, germinação, envelhecimento acelerado e atividade das enzimas envolvidas nos processos de germinação e deterioração de sementes. A adubação potássica não afeta a germinação e o vigor das sementes, enquanto a elevação da saturação por base, proporciona maior vigor de sementes de soja. Há aumento no teor de óleo e redução no teor de proteína em sementes de soja à medida que a dose de K2O é aumentada. Ocorre aumento de teor de proteínas em sementes de soja, produzidas sob maiores níveis de saturação por base. A atividade das enzimas piruvato quinase, esterase e álcool desidrogenase em sementes de soja é afetada pela concentração de potássio e saturação por base no solo. The chemical composition of seeds can be influenced by genetical and environmental factors and by the availability of nutrients in the soil during production, which consequently affect their vigor. Potassium can influence the activity of several enzymes present in plants. These enzymes are necessary in a number of reactions involved in the utilization of energy, starch synthesis, nitrogen metabolism and respiration. The effects of potassium fertilization and liming on the chemical composition, physiological quality and enzymes activities of soybean seeds were evaluated. The research was developed in the Seed Analysis Laboratory of the Agriculture Department and in the Plant Production Laboratory in the Food Science Department of the Federal University of Lavras, Lavras (UFLA). In soybean seeds of cultivar Msoy 8001 produced under two levels of base saturation (48% and 85%) and four doses. ha-1 of K2O, 0, 50, 100 and 200, oil and protein contents, seed germination, aging test and the activity of some enzymes involved in the seed germination and deterioration processes were evaluated. Seed germination and vigor are not influenced by fertilization with potassium. However, base saturation increases the vigor of soybean seeds. Highert doses of potassium increase oil content and reduce protein in soybean seeds. High base saturation level increases the protein content. The activities of the enzymes piruvate kinase, esterase and alcohol dehydrogenase are altered by the doses of potassium and levels of soil base saturation.

Em áreas tropicais há poucas informações disponíveis sobre o efeito da desfolha em milho, principalmente quando ocorre no período do enchimento de grãos. Objetivou-se neste trabalho avaliar os efeitos da remoção do limbo foliar durante o período de enchimento de grãos. Os experimentos foram instalados em 12/11/2005 e 21/12/2005 utilizando-se os híbridos GNZ 2004 e P 30F33. O delineamento experimental utilizado foi o de blocos casualizados com três repetições, em esquema fatorial, sendo duas posições de desfolha (acima e abaixo da espiga), duas porcentagens de desfolha (50% e 100%) e quatro estádios reprodutivos (R1, R2, R3 e R4), mais um tratamento adicional, no qual não foi realizada a retirada das folhas. A remoção do limbo foliar acima da espiga resultou em maiores perdas na produção de grãos em relação à remoção do limbo abaixo da espiga. O efeito da remoção do limbo foliar não variou com os estádios fenológicos considerados. Os efeitos na produtividade de grãos, da remoção do limbo foliar abaixo da espiga foram similares à remoção de 50% do limbo foliar acima da espiga em todos estádios fenológicos considerados. O efeito da remoção do limbo foliar sobre a porcentagem de plantas acamadas e quebradas foi de pequena magnitude.There is little information, in tropical areas concerning the effects of blade removal on maize crop characteristics. The aim of this research was to evaluate the effects of defoliation during the grain filling period. The experiment was arranged as a factorial complete randomized block design with blade removal at two different plant insertion points (above and below corn ear), with two percentages of blade removal (50% and 100%), and four phenological stages (R1, R2, R3, and R4). There were three blocks. Two identical experiments were installed, in 12/11/2005 and 21/12/2005. The hybrids GNZ 2004 and P 30F33 were evaluated in both experiments. Blade removal treatment above corn ear promoted higher grain yield loss in all reproductive stages in relation to the blade removal below corn ear. Blade removal treatment did not change with phenological stages. Results of blade removal below corn ear were similar to 50% of defoliation treatment above the ear. In addition, corn plant lodging was little affected by manual blade removal.

Com o objetivo de avaliar o efeito do condicionamento fisiológico e da qualidade de sementes sobre a época de florescimento de plantas de milho, foi realizado o presente trabalho. Foram utilizados lotes de sementes com qualidade fisiológica distinta de duas linhagens. Parte das sementes de cada lote foi condicionada em água, por período de 24 horas, totalizando quatro tratamentos, os quais foram avaliados na ausência e presença do "split" (sincronia de plantio) recomendado. Na área experimental, cada parcela foi composta por seis linhas de quatro metros cada uma, seguindo o delineamento de blocos casualizados com quatro repetições. Foram avaliadas a porcentagem da emergência das plantas em campo, altura das plantas, as datas em que ocorreram 50% e 100% de liberação do pólen e de emissão do estilo-estigma e, ainda, a data da ausência de liberação de pólen das plantas do parental masculino e receptividade do estilo-estigma para as do parental feminino e a data em que as sementes estavam no estádio de desenvolvimento LL3. Quando foram utilizadas sementes com alta qualidade e sem condicionamento, não houve necessidade de se efetuar o "split". O mesmo ocorreu com sementes não condicionadas e com alta qualidade do parental mais tardio, associadas com sementes de baixa qualidade e condicionadas do parental mais precoce. Foi observado, também, que a diferença existente no florescimento dos parentais praticamente se estendeu até o desenvolvimento das sementes no estádio LL3.In order to evaluate the effect of priming and physiological seed quality on maize flowering aiming the production of hybrid seeds, the following experimental procedure was carried out. Seed lots with distinct physiological quality of two lines were used. Part of each seed lot obtained was primed in water for 24 hours on a total of four treatments, which were evaluated in the presence and absence of the recommended split. In the experimental field, each plot was composed of six lines of four meters each, following the experimental design which consisted of a randomized complete block in four replications. The following variables were measured: percentage of field emergence, plant height, dates when 50% and 100% of pollen release and the emission of "stigma-style" occurred; moreover the date of no pollen release of male parent and receptivity of "stigma-style" towards the female parent and the date when the seeds were at stage ML 3 of development. When high quality seeds and no priming were used, it was not necessary to use the split. The same happened to high quality non-primed seeds of the later parent associated with low quality and primed seeds of the earlier parent. It was also observed that the difference in flowering date between the parents extended until the date of ML 3.

Estudar o acumulo de micronutrientes em funcao dos estadios fenologicos da cultura e de fundamental importância para subsidiar estrategias de definicao das quantidades e das epocas de realizacao de adubacoes na cultura, e das quantidades minimas que devem ser restituidas ao solo para fins de manutencao da fertilidade. Neste trabalho, objetivou-se avaliar o acumulo de micronutrientes em funcao dos estadios fenologicos da cultura, considerando dois hibridos de milho. O delineamento utilizado foi o DBC com quatro repeticoes, em esquema de parcelas subdivididas, sendo os dois hibridos de milho dispostos nas parcelas e, nas sub-parcelas, as epocas de coleta das plantas, considerando os estadios fenologicos da cultura do milho. Hibridos de milho acumulam quantidades minimas de B, Cu, Mn e Zn nos estadios iniciais de desenvolvimento da cultura, sendo os valores maximos acumulados obtidos a partir de 100 dias apos a emergencia. Os hibridos de milho avaliados acumulam zinco e cobre ate proximo a maturidade fisiologica, quando sao obtidos os acumulos maximos. Hibridos de milho acumulam micronutrientes em sua parte aerea na seguinte ordem decrescente: Zn>Mn>Cu>B. As quantidades de micronutrientes necessarias para produzir uma tonelada de graos de milho sao: 0,0009 kg de B; 0,019 a 0,020 kg de Cu; 0,042 a 0,046 kg de Mn; 0,100 a 0,194 kg de Zn.

Com o objetivo de avaliar o desempenho agronômico de nove cultivares de milho, sendo cinco destinadas ao cultivo com baixo investimento e quatro cultivares destinadas ao cultivo sob condições de alto investimento, foram conduzidos dois experimentos no ano agrícola 2004/2005, em Lavras, MG. Em um dos experimentos, utilizou-se a densidade de semeadura de 55.000 plantas ha-1 e, no outro, 65.000 plantas ha-1. Em cada experimento, as nove cultivares de milho foram avaliadas em três níveis de adubação: (1) 300 kg ha-1 de 8-28-16 na semeadura, mais 200 kg ha-1 de 30-00-20, em cobertura; (2) 400 kg ha-1 de 8-28-16 na semeadura, mais 300 kg ha-1 de 30-00-20, em cobertura e (3) 500 kg ha-1 de 8-28-16 na semeadura, mais 300 kg ha-1 de 30-00-20 e 150 kg ha-1 de uréia, em cobertura. Os resultados permitiram concluir que a adubação de 500 kg ha-1 de 8-28-16 na semeadura, mais 300 kg ha-1 de 30-00-20 na primeira cobertura e 150 kg ha-1 de uréia na segunda cobertura proporciona aumento significativo na produtividade de grãos e na altura das plantas. O aumento da densidade de semeadura de 55.000 plantas ha-1 para 65.000 plantas ha-1 não influenciou a produtividade de grãos, mas, interferiu na altura de plantas e de espigas e na prolificidade. As cultivares destinadas ao alto investimento apresentam maior prolificidade, maior altura de planta e maior produtividade de grãos do que as cultivares destinadas ao baixo investimento. With the aim of evaluating the agronomic traits in nine maize cultivars, five being considered for cultivation of low investment and four maize crops considered for high investment, two trials were carried out in the agricultural year 2004/2005, in Lavras, MG. One of the trials was carried out with plant density of 55.000 plants ha-1 and the other, 65.000 plants ha-1. In each trial the nine maize crops were carried out in three fertilizing levels: (1) 300 kg ha-1 of an 8-28-16 formula at the sowing date, with an additional 200 kg ha-1 of a 30-00-20 formula, for covering; (2) 400 kg ha-1 of 8-28-16 at the sowing date, with an additional of 300 kg of 30-00-20, for covering; (3) 500 kg ha-1 of 8-28-16 at the sowing date, with an additional of 300 kg ha-1 of 30-00-20 and 150 kg ha-1 of N, for covering. The results allowed concluding that fertilizing with 500 kg ha-1 of 8-28-16 at the sowing date, with an additional 300 kg ha-1 of 30-00-20 and 150 kg ha-1 of N, for covering, the maize crops showed expressive increase in the productivity of grains and plant height. The increase of plant density from 55.000 plants ha-1 to 65.000 plants ha-1 did not influence the productivity of the grains, but interfered in the plant height, ear length, and prolificacy. The maize crops of high input showed higher prolificacy, higher plant height and higher productivity of grains in relationship to the crops of low investment.