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A lagarta do cartucho é uma das principais pragas do milho, sendo controladas principalmente por inseticidas químicos, porém está tática de manejo pode ocasionar riscos ao meio ambiente e a saúde humana. A utilização de cultivares resistente pode diminuir a população da praga ocasionando menos danos as lavouras. Sendo assim este trabalho teve como objetivo avaliar a resistência de cultivares de milho a Spodoptera frugiperda. Foram utilizados 11 cultivares de milho em testes de preferência alimentar com e sem chance de escolha, e teste de antibiose. Empregou-se o delineamento experimental inteiramente casualizado para o teste sem chance, e blocos casualizados para o teste com chance de escolha, ambos com seis repetições, e o delineamento inteiramente casualizado com 30 repetições para o teste de antibiose. Nos testes de preferência, avaliou-se a atratividade aos 1, 3, 5, 10, 15, 30, 60, 120, 360, 720 e 1440 minutos e a porcentagem de injúria. No teste de antibiose avaliou-se os aspectos biológicos de 30 lagartas por tratamento. A cultivar AS 1581 apresentou características de resistência na categoria não preferência para alimentação. As cultivares TRUCK e IAC 8390 apresentaram características de resistência na categoria antibiose a S. frugiperda.

ABSTRACT: Unchanged reference values of grain nutrient contents for corn have been used for over 20 years, despite yield increases, the development of new hybrids, and modifications to cropping systems, especially the establishment of in-season second crops and the wide adoption of no-tillage. This study measured macro- and micronutrient contents in corn grains from different regions, in the first (summer) and second (fall) crop, to update the reference values of estimated nutrient removal. A secondary objective was to determine whether there were correlations between grain nutrient contents and grain yields and densities. In this study, 175 corn grain samples of experiments on cultivar evaluation and 22 samples from soil management trials from five states (SP, PR, MG, MT, and MS) were used. Grain nutrient contents were ranked as follows: N > K > P > Mg > S (g kg−1) and Ca > Zn > Fe > Mn > B > Cu (mg kg−1). Content values for half of the nutrients analyzed were negatively correlated with yield and/or seed weight, whereas grain density was not correlated with nutrient contents. For the first crop of corn, the N, S, and Cu contents clearly decreased with increases in grain yield and seed weight, indicating a lower nutrient removal at higher yields. The great variability of results among environments makes it difficult to differentiate between the first and second crop of corn. The reference values currently in use overestimate the removal of N, P, K, Ca, Mg, S, and Zn grain contents, but underestimate Cu and B in corn. The results of this study can be used to update the reference values of nutrient contents of corn grains to better estimate nutrient removal from the soil.

This study aimed to determine the levels of fumonisins produced by F. verticillioides and FUM gene expression on Bt (Bacillus thuringiensis) and non-Bt maize, post harvest, during different periods of incubation. Transgenic hybrids 30F35 YG, 2B710 Hx and their isogenic (30F35 and 2B710) were collected from the field and a subset of 30 samples selected for the experiments. Maize samples were sterilized by gamma radiation at a dose of 20 kGy. Samples were then inoculated with Fusarium verticillioides and analysed under controlled conditions of temperature and relative humidity for fumonisin B1 and B2 (FB¬1 and FB2) production and FUM1, FUM3, FUM6, FUM7, FUM8, FUM13, FUM14, FUM15 and FUM19 expression. 2B710 Hx and 30F35 YG kernel samples were virtually intact when compared to the non-Bt hybrids that came from the field. Statistical analysis showed that FB¬1 production was significantly lower in 30F35 YG and 2B710 Hx than in the 30F35 and 2B710 hybrids (P < 0.05). However, there was no statistical difference for FB2 production (P > 0.05). The kernel injuries observed in the non-Bt samples have possibly facilitated F. verticillioides penetration and promoted FB1 production under controlled conditions. FUM genes were expressed by F. verticillioides in all of the samples. However, there was indication of lower expression of a few FUM genes in the Bt hybrids; and a weak association between FB1 production and the relative expression of some of the FUM genes were observed in the 30F35 YG hybrid.

O objetivo deste trabalho foi avaliar o acúmulo de matéria seca e de nutrientes de plantas forrageiras consorciadas com o milho safrinha, em função da adubação nitrogenada. As espécies Urochloa brizantha cv. Marandu, U. decumbens cv. Basilisk, U. ruziziensis cv. Comum e Panicum maximum cv. Tanzânia, com semeadura em meados de março, foram avaliadas em quatro municípios paulistas, em consórcio com o milho. Utilizou-se o delineamento experimental de blocos ao acaso, com quatro repetições, em parcelas subdivididas. Nas parcelas, foram avaliados os consórcios e nas subparcelas, quatro doses de nitrogênio em cobertura (0, 30, 60 e 90 kg ha-1). Foi determinado o acúmulo de matéria seca e de nutrientes pelas plantas forrageiras em três épocas: no florescimento, na maturidade fisiológica do milho e por ocasião da dessecação das forrageiras, em outubro. O acúmulo de matéria seca das forrageiras intensifica-se após a colheita do milho safrinha. Quando as forrageiras são semeadas na entrelinha do milho, a adubação nitrogenada em cobertura não interfere no acúmulo de matéria seca e de nutrientes pelas forrageiras, e o consórcio não afeta a produtividade de grãos de milho safrinha.

The aim of this study was to verify the relationship between the occurrence of ENSO phenomena (ElNiño/ La Niña), rain and yield variability in the Middle Paranapanema Region, SP, Brazil. The yield data were obtainedfrom the Agricultural Economy Institute (IEA) and the meteorological data from the Department of Ecophysiology andBiophysics of the Campinas Agronomic Institute (IAC). Data from 30 years (1976 to 2007) of summer maize yield,ten-day rainfall and the occurrence of ENSO phenomena were used/considered. The technological trend of the seriesin the region was disposed of in accordance with the model of Cunha et al. (2001). A strong correlation between yieldand rain was observed. However we did not find a relationship between rainfall and the occurrence of ENSO in theMiddle Paranapanema Region.

The objective of this work was to verify the potential of top cross hybrids and of partially endogamic lines (S3) obtained from commercial maize hybrids. The 27 top cross hybrids, two commercial checks and the tester IA 33 were evaluated by complete block design with three replications, in two years (2005/2006 and 2006/2007) and inthree locations (Campinas, Mococa and Palmital) of São Paulo State. The following traits were evaluated: male flowering, plant height, ear height, percentage of lodging and broken plants and grain weight corrected to 14% moisture. The effects of general combining ability and the heterobeltiosis of the top cross hybrids were considered. Top cross hybrids were verified with grain weight superior or similar to the commercial checks, proving the productive potential of the top cross hybrid. The hybrid IA 33 x HI 9-19-1 outstanding with high grain yield and heterobeltiosis, and the lines HI 9-19-1 and HG 7-12-1 showed high combining ability estimates in the three locations.

The scarce information about the cultivars available in the market discourages the diversification of the genetic materials used for green corn production. In this subject, two cultivars of the same company predominate, corresponding to more than 75 percent of the cultivated area. The objective of this work was to evaluate agronomic performance of green maize cultivars in the Sao Paulo State, Brazil, in late season crop. The experiments were conducted in Campinas, Mococa and Capão Bonito, São Paulo, Brazil, in March 2009. Treatments consisted of cultivars AS 1592, AG 1051, AG 4051, BM 3061, GNZ 2004, Cativerde, 6B6229V and 6B6277V and a randomized block design was used with split-plots and four replications. Sowing times were located in the main plots and the management level in the split-plots. The plots consisted of six 5.0 m long rows spaced 0.8 m apart. The cultivars showed above 69 percent of marketable green ears. All cultivars showed green ear length and diameter suitable to be commercialized asfresh green spike. Hybrids AG 1051, AG 4051 6B6229V and 6B6277V presented higher percentages of marketable green ears, being good alternatives for green maize production in late season crops.

Este trabalho teve como objetivo avaliar, em condições de campo, a resposta de duas cultivares de milho com características genéticas distintas em Latossolo Vermelho em seis níveis de compactação. O experimento foi conduzido em faixas, no delineamento de blocos completos casualizados, com quatro repetições. Utilizaram-se os híbridos de milho DKB 390 e DAS 2B710. Após a semeadura do milho, coletaram-se amostras indeformadas de solo nas profundidades de 0-10, 10-20 e 20-30 cm, para determinação de propriedades físicas do solo e índice S. No estádio de maturidade fisiológica dos grãos do milho, foram determinados: a altura das plantas, a altura de inserção da primeira espiga, o diâmetro do segundo colmo acima do solo e a massa de matéria seca das plantas. As espigas foram colhidas e debulhadas para determinação da produtividade de grãos, corrigida para a umidade-padrão de 13 %, calculando-se também o número de espigas por planta e o índice de colheita. O índice S apresentou correlação positiva com a produtividade, porém, abaixo do limite de S < 0,035, estabelecido para uma condição de solo desestruturado, ocorreram perdas acentuadas na produtividade de milho. Os híbridos simples de milho DKB 390 e DAS 2B710 não apresentaram diferenças quando submetidos aos diferentes níveis de compactação. A produtividade dos híbridos de milho foi significativamente menor quando a resistência do solo à penetração atingiu 2,15 MPa.The purpose of this study was to evaluate, under field conditions, in Colina-SP, Brazil, the response of two genetically different corn cultivars to six compaction levels of an Oxisol. The experiment was arranged in a randomized complete block design, with strip plots and four replications. The corn hybrids DKB 390 and DAS 2B710 were used. After corn seeding, non-deformed soil samples were collected from the layers 0-0.10, 0.10-0.20 and 0.20-0.30 m to determine soil physical properties and the S index. At the seed maturity stage, plant height, height of ear insertion, stem diameter and plant mass were measured. The ears were harvested and threshed to determine grain yield (moisture corrected to standard 13 %) and the number of ears per plant and harvest index were also calculated. The S index was positively correlated with grain yield. However, below the S threshold of £ 0.035, established for soil without structure, the corn yield losses were great. The simple hybrids DKB 390 and DAS 2B710 did not differ under different soil compaction levels. The grain yields of both were significantly lower when soil resistance to penetration reached 2.15 MPa.

Este trabalho teve como objetivo avaliar, no campo, a resposta de duas cultivares de milho em um Latossolo Vermelho, em seis níveis de compactação, quanto ao desenvolvimento do sistema radicular, bem como caracterizar a compactação do solo a partir do intervalo hídrico ótimo (IHO). O experimento foi realizado em faixas, no delineamento de blocos completos casualizados, com quatro repetições. Utilizaram-se os híbridos de milho DKB 390 e DAS 2B710. Após a semeadura do milho, coletaram-se amostras indeformadas de solo para a determinação de propriedades físicas do solo e do IHO. No estádio do pendoamento do milho, retiraram-se três amostras por parcela na entrelinha, nas profundidades de 0-10, 10-20 e 20-30 cm, em cada parcela, para determinação de diâmetro médio, densidade do comprimento radicular e massa de matéria seca das raízes. O IHO foi igual a zero quando o solo atingiu a densidade crítica de 1,46 kg dm-3, correspondente a 92 % da densidade máxima do solo. Com a compactação, houve aumento da produção de matéria seca das raízes, da densidade do comprimento radicular e do diâmetro radicular e na profundidade de 0-10 cm, o aumento da massa de matéria seca e da densidade radicular se dá até a resistência do solo à penetração de 1,23 e 1,43 MPa, respectivamente. Houve correlação negativa entre a massa de matéria seca, a densidade e o diâmetro radicular com a produtividade do milho irrigado, mostrando que essas variáveis são bons indicadores da compactação do solo.The objective of this study was to evaluate, under field conditions, in Colina-SP, Brazil, the response of two corn cultivars to six soil compaction levels of an Oxisol regarding the root system development, and to characterize soil compaction by the least limiting water range (LLWR). The experiment was arranged in a randomized complete block design, with strip plots and four replications. The corn hybrids DKB 390 and DAS 2B710 were used. After corn sowing, undisturbed soil samples were collected to determine physical properties and LLWR. At the tasseling stage of the corn plants, three soil samples per plot were taken from the crop inter-row, from the layers 0-10, 10-20 and 20-30 cm, to measure mean root diameter, length density and dry mass. The LLWR was equal to zero when soil density reached the critical level of 1.46 t m-3, corresponding to 92 % of the maximum soil density. Greater soil compaction resulted in greater root dry mass, length density, and diameter. In the 0-10 cm layer an increase in root dry mass and density was possible up to a penetration resistance of 1.23 MPa and 1.43 MPa, respectively. Root dry mass, density and diameter were negatively correlated with the yield of irrigated corn, and therefore represent good soil compaction indicators.

Objetivou-se avaliar o teor de matéria seca (MS) e a participação percentual das frações da planta em híbridos de milho colhidos em diversos estádios de maturação. Utilizou-se um delineamento em blocos casualizados, com esquema fatorial 8 × 6 × 2, composto de oito épocas de corte, seis híbridos de milho e duas safras (2001/2002 e 2002/2003). Os híbridos CO 32, AG 5011, P 3041, DKB 333B, AG 1051 e Z 8550 foram colhidos ao atingirem 50% de florescimento masculino, 15 dias após esta data e, posteriormente, a cada semana, totalizando-se oito cortes. As plantas atingiram o teor de MS para ensilagem (32 a 35% MS) 92 a 112 dias após a semeadura (DAS). O avanço da maturação aumentou os teores de MS das frações colmo (de 16,9 para 28%), folha (de 23,2 para 48,8%), sabugo (de 10,0 para 55,5%) e grãos (de 50,4 para 70,9%). Além disso, promoveu aumento das proporções de MS acumulada nos sabugos (de 1,6 para 9,2%) e grãos (de 0 para 43,4%) e redução na proporção de colmo (de 63,4 para 29,5%) e folhas (de 27,5 para 10,8%). A comparação dos híbridos de milho colhidos em estádios fisiológicos diferentes considerando apenas a participação das frações na planta deve ser feita com muito critério, uma vez que a época de corte pode alterar significativamente a composição morfológica da planta.The objective of this experiment was to evaluate the dry matter (DM) content and the percent participation of fractions that compose the plant in corn cultivars harvested at different maturity stages. A randomized block design with an 8 × 6 × 2 factorial scheme composed of eight harvesting times, six corn cultivars and two harvest years (2001/2002 and 2002/2003) was used. Cultivars CO 32, AG 5011, P 3041, DKB 333B, AG 1051 and Z 8550 were harvested when they reached 50% male flowering; 15 days after this date and later, each week, totalizing eight harvesting times. The plants reached the recommended DM content for silage production (32 to 35% DM) between 92 and 112 days after sowing (DAS) at the evaluated years. The maturity advancement resulted in increases in DM content in stem (from 16.9 to 28%), DM content in leaves (from 23.2 to 48.8%), DM content in cob (from 10 to 55.5%), and DM content in grains (from 50.4 to 70.9%). Furthermore, it resulted in increases in cob (from 1.6 to 9.2%) and grain proportion (from 0 to 43.4%), and decrease in stem (from 63.4 to 29.5%) and leaves proportion (from 27.5 to 10.8%). The corn cultivars showed distinct growing pattern for the evaluated variables. Therefore, plants harvested at different physiologic states can only be compared with fractions participation with considerable discernment, once the harvesting time can modify significantly the plant morphological composition.

Objetivou-se estabelecer correlações entre características quantitativas e qualitativas e avaliar a influência dessas características sobre a produção e a qualidade do milho para silagem. Utilizaram-se dados do Programa de Avaliação de Cultivares de Milho para Silagem IAC/APTA/ESALQ para cálculo das correlações de Pearson entre as variáveis. A produção de matéria seca (MS) digestível foi afetada tanto pelas produções de massa e de grãos quanto pelas digestibilidades da planta e do colmo. A produção de matéria seca digestível apresentou os maiores coeficientes de correlação com a produção de MS (0,85); com as produções de grãos na ensilagem (0,60) e na maturidade (0,68); com produção de matéria verde (0,47); e com o índice de espigas (0,48). Os coeficientes de correlação entre a produção de matéria seca digestível e a digestibilidade da planta inteira (0,44) e da fração colmo (0,38) foram inferiores aos obtidos para a produção de matéria seca. A digestibilidade da planta dependeu principalmente da digestibilidade do colmo (0,60) e dos parâmetros relacionados aos grãos. Na ausência de informações específicas sobre os cultivares de milho para silagem, pode-se optar por aqueles de maior produção de grãos à maturidade, em razão da elevada correlação dessa característica com produção de matéria seca e com produção de matéria seca digestível.The objective of this work was to establish correlations between quantitative and qualitative variables and to evaluate their influence on the corn quality for ensilage production. Data from the Corn Hybrids for Silage Evaluation Program were used (IAC/APTA/ESALQ). Pearson correlations between the variables were calculated. The digestible dry matter (DM) production was affected not only by forage and grain productions, but also by the whole plant and stem digestibility. The digestible dry matter production presented the highest correlation coefficients with the total dry matter production (0.85) and with the grain production at ensiling (0.60) and maturity (0.68), production of fresh forage (0.47) and with the plant ears index (0.48). The correlation coefficients between the digestible DM production and the whole plant digestibility (0.44) and the stem fraction (0.38) were lower than those observed for the DM production. The whole plant digestibility depended mainly on the stem digestibility (0.60) and on parameters related to the grains. It may be concluded that when specific information on corn hybrids is not available, those with higher production of grains at maturity are selected due to their elevated correlation with DM production and digestible DM.

Gray leaf spot is an important maize disease in São Paulo State. Due to its relevance, the effect of this disease on maize grain yield was studied during the 2004 to 2008 autumn-winter seasons. Experiments were carried out to evaluate corn cultivars, comprising 44 to 60 simple and triple hybrids, being 19 trials in 2004, 15 in 2005, 16 in 2006, 16 in 2007 and 15 in 2008. The evaluations of disease severity were done at the kernel dough stage, ascribing notes 1 to 9 (for 0%; 1%; 2.5%; 5%; 10%; 25%; 50%; 75% and more than 75% affected leaf area, respectively). Significant negative correlation between gray leaf spot severity and grain yield was detected in 16 of the 35 trials where the disease occurred. In order to quantify the effect of gray leaf spot on yield of these 16 trials, attempting to minimize the dispersion caused by differences of yield potential, cultivars tolerance to the disease and other factors, cultivars were grouped into categories of disease intensity based on the Scott-Knott test at 5%, and means for severity and yield were calculated for each category. The adjustment of linear equations to these data allowed to estimate the yield reduction as a function of disease severity, for the intervals studied in each trial, that was on average 238 kg ha-1 (4%) with note 2, 634 kg ha-1 (11%) with note 3, 1006 kg ha-1 (17%) with note 4 and 1574 kg ha-1 with note 5, in relation to the groups with greatest gray leaf spot resistance which showed mean note 1.4 and mean grain yield 5655 kg ha-1. These results indicate that even with low disease severity a significant maize yield loss can be observed, demonstrating the importance of the use of genetic resistance in the control of gray leaf spot and to reduce losses in maize grain yield.

This work aimed to study populational dynamics of aphids on off-seasonmaize genotypes over the culture cycling and the influence of these genotypes onparasitoids of aphids. Fifty-three simple and/or triple hybrids were evaluated in additionto the AL Bandeirante variety, in Cruzália county, São Paulo State, during autumn-wintercrop of 2006. The evaluation was carried out at 39, 53, 67 and 75 days after the sowing,using 5 plants per sample in the two central lines. A cardboard was placed on the basalpart of the whorl with an opening of 3 x 3 cm, totalizing 45 cm2 per sample, counting, inthe inside of the whorl, the number of apterous adults, alate adults, nymphs and parasitized (mummy). The aphids identified were Rhopalosiphum maidis and Rhopalosiphum padiand the parasite was only Lysiphlebus sp. The most important period of aphids occurrencein off-season maize was after 53 days from emergency, before tassel opening. Populationof aphids and parasitoids differed among cultivars, where AS 1567 and 30F87 stood outwith the most quantity of nymphs and parasitism, respectively.

Kernel appearance is the physical quality parameter in Brazilian marketing instead of the quality standard tests. The cultivars with dent and semi-dent kernels are dismissed because their kernels are considered more susceptible to breakage. The aim of this study was to verify whether the appearance could be used to evaluate the kernel hardness and to determine relationship among kernel density parameters and breakage susceptibility in maize hybrids grown off-season. Three trials were performed in Assis, Cruzália and Votuporanga (SP) in 2003, using a complete randomized block design with 42 single and three-way crosses and three replications. Yield, kernel hardness appearance, kernel weight, percentage of kernel floaters in sodium nitrate standard solution, test weight and kernel breakage susceptibility were evaluated. The data were submitted to the analysis of variance by the F test and treatments were compared by Duncan test (P < 0.05). Pearson correlations among the parameters were calculated using SAS program. The evaluation of kernel hardness appearance was not efficient to screen cultivars regarding the kernel density and breakage susceptibility. There was no correlation between yield and kernel physical quality. Most of the hybrids had high kernel density, showing high average of test weight (825 g L-1) and very low percentage of kernel floaters. The kernel floaters were higher in the cultivars DAS 2C577 (82%), DKB 390 (33%) and DAS 2C522 (18%). All cultivars had low breakage susceptibility and with the following standing out negatively: Fort, A 4450, Exceler, XB 7011, A 2560 and 30F98 (2,7 a 4,5% of weight). In general, the breakage susceptibility was not correlated to kernel density. Only the kernel floaters were significantly associated to breakage susceptibility, but the correlation was very low (0,10).

Zinc deficiency usually occurs in maize grown in Brazilian acidic soils. The aim of this study was to evaluate commercial maize cultivars for their Zn uptake and utilization efficiency. A greenhouse experiment using nutrient solution with young plants was carried out at Campinas, State of São Paulo, Brazil, in 2002. Treatments consisted of: 0.0; 0.1; 0.2; 0.4 and 0.8 mg L-1 Zn in the main plots and 24 commercial maize cultivars in the subplots, in a randomized complete block design. Zn concentration in shoot dry matter (SDM) ranged from 28.4 to 41.6 mg kg-1 among cultivars, clearly indicating a dilution effect, since a negative relation between SDM and plant height was shown. Total Zn-shoot content was a good parameter to discriminate cultivars, once correlated with plant height and SDM (r = 0.66** and r = 0.67**, respectively). Analysis of variance and polynomial regression for total Zn-shoot content was highly significant among cultivars and for the interaction cultivar vs Zn-concentration. Plants under low Zn presented up to three-fold differences among efficiency index values (E.I. = 8.59 to 26.42 mg² DM mug-1 Zn). The results with young plants indicated six maize cultivars classified as Zn-efficient and responsive (AG 7575, Tork, AL Bandeirante, AL 34, AGN 2012, Master) and six cultivars classified as efficient non-responsive (P30F33, P30K75, P30F80, AS 1533, DOW 8420 e AL 30). Other nutrient concentrations in the SDM were within normal limits (K, P, Ca, Mg, Cu, Fe, Mn) for maize young plants.Nos solos ácidos são comuns os casos de deficiência de zinco (Zn) na cultura do milho. O objetivo do presente trabalho consistiu em avaliar cultivares comerciais de milho quanto à eficiência na absorção e utilização de Zn. O experimento foi conduzido em Campinas, SP, Brasil, 2002, em casa de vegetação com plantas jovens em solução nutritiva, utilizando blocos ao acaso em parcelas divididas, sendo os tratamentos: 0,0; 0,1; 0,2; 0,4 e 0,8 mg L-1 de Zn e 24 cultivares comerciais de milho. Os teores de Zn na parte aérea (PA) variaram de 28,4 a 41,6 mg kg-1 (1,46 vez) entre as cultivares. O conteúdo total de Zn na PA foi o parâmetro que melhor se correlacionou com a altura de planta (r = 0,66**) e com a matéria seca de parte aérea (MSPA) (r = 0,67**), permitindo diferenciação das cultivares. A análise da variância e a regressão polinomial para essa variável revelaram diferenças significativas entre cultivares, bem como para o índice de eficiência, cujos valores variaram de até três vezes (8,59 a 26,42 mg² MS mig-1 Zn) em condições de baixo Zn. Os resultados com plantas jovens indicaram seis cultivares como eficientes e responsivas (AG 7575, Tork, AL Bandeirante, AL 34, AGN 2012, Master) e outras seis como eficientes e não-responsivas (P30F33, P30K75, P30F80, AS 1533, DOW 8420 e AL 30). Os teores de K, P, Ca, Mg, Cu, Fe e Mn na MSPA, estiveram dentro dos limites normais para plântulas de milho.

The objective of this work was to obtain the accumulation curves of dry matter and nutrients of five maize cultivars grown by farmers in the state of São Paulo, Brazil, differing in respect to the origin of the germoplasm and to the maturation date within each group. The distribution of dry matter and nutrients in leaves, stalk and ears was also studied. The experiment was carried out in Palmital County during the cropping year of 2000/01 under no-till system. Three tropical maize cultivars (AG 1051, BR 3123 and BRS 4157) and two temperate cultivars adapted to the Brazilian climate (DKB 212 and P32R21) were selected. To determine the accumulation curves, plants were sampled at 15-day intervals up to the 105th day after emergence, whereas to study the distribution of dry matter and nutrients in the plant, samples were collected at the end of the male silking and at grain physiological maturity, according to each cultivar. Maximum accumulation of dry matter and nutrients was estimated by means of polynomial regression equations. Nutrient content decreased with plant growth after the 30th day from emergence. For all cultivars, nutrient and dry matter accumulation reached maximum values before the grain physiological maturity, except for Fe whose accumulation continued beyond this stage. Most of the nutrients in the plant were accumulated before silking, except P, Fe and Zn. Only 13% of K in the plant was accumulated after silking. The introduced temperate climate cultivars accumulated more Cu in the whole plant cycle and showed higher proportion of N, Ca, Mg, Cu, Fe, Mn and Zn accumulating after silking, expressed as a percentage of the total amount accumulated, in comparison to the tropical cultivars. The late maturing cultivars, AG 1051 and DKB 212, showed the highest values of maximum accumulation of Mg; also, these maximum values occurred at a later period for these cultivars than for the others. The tropical cultivars were better adapted to the local warm condition than the temperate ones, and also showed higher accumulation of dry matter, K, Ca, Mg, B, Mn and Zn. Only a small proportion of Ca in the plant was accumulated in the ears, while N, P, S and Zn were mostly concentrated in this plant organ.

The incidence of Corn stunt diseases symptoms and virus infection symptomswas surveyed on 22 cultivars sowed in the “Safrinha” growing season and in the “Summer”growing season at several localities in São Paulo, Goiás and Minas Gerais States. These surveywas made from Safrinha 1999 until Safrinha 2000. Leaves samples from plants with Corn stuntdiseases symptoms were submitted to DNA extraction and to PCR test to determine theincidence index of infection by phytoplasma and by spiroplasma. Leaves samples with virusinfection symptoms were submitted to RT-PCR to confirm the virus identification. In general, the incidence of Corn stunt diseases symptoms was higher in the Safrinha growing season thanin the Summer growing season, except in São Paulo state where the incidence of these diseaseswas similar on both seasons. The mollicute infection was detected in 103 samples, among 390submitted to PCR test. The simultaneous infection by both spiroplasma and phytoplama wasdetected only in 6 samples. Taken into account the total of positive samples to mollicute infection,the incidence of spiroplasma and phytoplasma was similar. However, only in the Safrinha growingseason it was observed that only one of these mollicute predominated. This predominancealternated from spiroplasma in Safrinha 1999, to phytoplasma in Safrinha 2000 and spiroplasmain Safrinha 2001. The Maize Rayado Fino Virus (MRFV) and the Maize Dwarf Mosaic Virus(MDMV) were detected in variable levels of incidence, just at some localities and growingseason evaluated, in general with incidence levels lower than the ones of Corn stunt diseases.

O artigo não apresenta resumo em português.

The aim of this work was to evaluate the implementation of the Integrated Crop-Livestock (ICL) in beef cattle farms where the corn was planted directly on the pasture, under no-till system, in the first year. The Crop-Livestock Integration (CLI) models evaluated consisted of Brachiaria decumbens pastures intercropped with corn in the no tillage system. However, the evaluated CLI system differed from the usual system because it did not use the conventional tillage in the first year, while the conventional soil preparation and sowing of grass is used by most of the Brazilian farms. The results show that in the first year the period of time spent planting and side-dressing nitrogen on corn was longer compared to the following years, mainly due to the lack of uniformity of the ground surface, once no conventional tillage was used to prepare the soil and these operations were performed with own implements for direct planting. Therefore, many seeds were placed either very deep or not buried, thus compromising the crop and becoming necessary to replant the corn with a manual planter. From the second year on, even though the conditions were not ideal, the ground surface became more accessible for the sowing and cultivation of corn, after the tillage of the first year. The time spent in most operations performed was longer than usual, especially planting and side-dressing nitrogen on the corn so that the discs did not chop off plants due to the irregularities of the ground surface. Productivity dropped due to the problems already discussed that contributed to a lower income. It is therefore concluded that, under these experimental conditions, the conventional tillage is imperative when implementing the CLI system, even considering the soil management improvements observed from the first to the second year.

Ten elite maize (Zea mays L.) lines were crossed in a complete diallel scheme and the single-cross hybrids obtained were assessed at four experimental stations of the Agronomic Institute of Campinas, in São Paulo State, Brazil. The experiments were set up in a randomized complete block design with three replications, including four commercial checks. The experimental plots consisted of two 5-m rows spaced at 0.9 m, with a total of 50 plants. The traits assessed included: days to mid-tassel pollen shed (DPS), plant height (PH), ear height (EH), grain yield, corrected for a 50-plant stand and 14% moisture (GY corr.), and resistance to Phaeosphaeria maydis and Puccinia polysora. General and specific combining ability effects (GCA and SCA) were determined. There was extensive genetic variability among hybrids with the best hybrids (HS 04 x 10 and HS 10 x 11) not differing from the commercial checks. The lines with the greatest potential for hybrid synthesis included: L 10, L 11 and L 13, because they had higher GCA for yield, moderate resistance to P. maydis and reduced EH. The greatest contribution to reduction of the Phaeosphaeria stain was obtained with L 5. The magnitude of the GCA relative to the total variation indicated that additive effects predominated for resistance to P. maydis and P. polysora. Significant SCA (P < 0.01) was also found, indicating dominance effects as well.Cruzaram-se dez linhagens-elite de milho em esquema dialélico completo e os híbridos simples obtidos foram avaliados em quatro Núcleos Experimentais do Instituto Agronômico de Campinas, SP, Brasil. Os ensaios foram instalados sob delineamento de blocos casualizados com três repetições, incluindo quatro testemunhas comerciais. As parcelas consistiram em duas linhas de 5 m espaçadas por 0,90 m, contendo 50 plantas. Avaliaram-se os caracteres: dias para o florescimento masculino (DPS), altura da planta (PH) e da espiga (EH), produtividade de grãos corrigida para estande ideal de 50 plantas e 14% de umidade (GY corr.) e resistência a Phaeosphaeria maydis (Pm) e a Puccinia polysora (Pp). Estimaram-se os efeitos da capacidade geral e específica de combinação das linhagens. Houve grande variabilidade genética entre os híbridos, sendo que os melhores (HS 04 x 10 e HS 10 x 11) não diferiram das testemunhas comerciais. As linhagens de maior potencial para síntese de híbridos no conjunto em questão foram: L 10, L 11 e L 13, por aliarem alta GCA para produtividade, resistência moderada a P. maydis e redução da altura da espiga. A maior contribuição para redução da mancha de Phaeosphaeria foi proveniente de L 5. A magnitude da GCA em relação à variação total corroborou a natureza preponderantemente aditiva da resistência às doenças estudadas. A presença da SCA significativa (P < 0,01) foi também confirmada, indicando a existência de efeitos de dominância.

RESUMO Diversas tecnologias de milho geneticamente modificado (Bt) foram liberadas comercialmente desde 2007 visando principalmente o controle da lagarta-do-cartucho, Spodoptera frugiperda (Lepidoptera: Noctuidae). O objetivo deste trabalho foi avaliar a eficiência de híbridos transgênicos (Bt) e convencionais (não Bt) no controle lagarta-do-cartucho, submetidas ou não a inseticidas. Para isso, foram conduzidos ensaios em três localidades do estado de São Paulo nas safrinhas de 2009, 2010 e 2011, com delineamento experimental de blocos casualizados, em esquema fatorial 5x4, 5x4 e 8x4, respectivamente. O primeiro fator correspondeu ao número de híbridos comerciais de diferentes empresas. O segundo fator foi constituído pela utilização de diferentes manejos de controle do inseto. Para a avaliação dos danos ocasionados pela lagarta-do-cartucho, foram realizadas amostragens ao acaso de 20 plantas por parcela, aplicando-se uma escala de notas visuais, atribuindo notas que variam de 0 (sem dano) a 9 (cartucho totalmente destruído) e obtido a produtividade de grãos. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5% de probabilidade, para cada parâmetro avaliado em cada localidade. Os híbridos transgênicos proporcionaram redução nas notas de danos atribuídas a lagarta-do-cartucho e as proteínas Cry 1F, Cry 1A105 e VIP3Aa20 foram as mais eficientes na redução do dano foliar. A pulverização mostrou-se uma estratégia eficiente em reduzir os danos foliar provocados pela praga. A combinação da pulverização com híbrido transgênico, de modo geral, mostrou ser uma boa estratégia para redução de dano foliar, especialmente quando foi utilizada a proteína Cry 1Ab, comprovadamente de menor eficiência para redução dos danos causados pela praga.