Resumo em Inglês:

ABSTRACT The gladiolus flower is classified as insensitive to ethylene. Thus, the signals that initiate senescence are poorly understood. This study evaluated the role of abscisic and gibberellic acids on postharvest senescence of 3 cultivars of cut gladiolus flowers (Gladiolus grandiflora Hort.). Stalks were harvested and placed in test tube containing 100 mL distilled water or an aqueous solution of abscisic acid (100 and 150 µM ABA), gibberellic acid (100 µM GA3), and fluridone (1 mM) for 24 h. Subsequently, flower stalks were placed in a test tube with distilled water, and the following variables were determined: stem longevity, fresh weight change, water uptake rate and transpiration rate during the vase life, as well as membrane stability index and lipid peroxidation in 5 stages of flower development. In another experiment, the florets were removed by cutting down the pedicel. After removal, florets were placed in a beaker containing 10 mL distilled water or the following solutions: 100 or 150 µM ABA; 100 µM GA3; 1 mM fluridone; and 100 µM ABA + 100 µM GA3, followed by immersion in distilled water after 24 h in each treatment. Fresh weight change and transpiration rate of florets were assessed every 24 h. Abscisic acid is involved in the induction of senescence-related events in gladiolus flowers, such as high loss of membrane stability and abnormal flower opening. GA3 regulates the action of ABA in the maintenance of cell membrane and opening of gladiolus flowers.

Resumo em Inglês:

ABSTRACT In order to investigate the existence of a possible abscission zone in the binding region between the peduncle and the coffee fruit, as well as the biochemical events involved in fruit ripening, we studied peduncles and fruits of Coffea arabica L. cv. “Icatu amarelo”. Coffee fruits were harvested at different maturation stages by using specific intervals of detachment force. It was observed a breakdown in the cells of the connecting region between peduncles and fruits throughout the maturation process. This disruption is probably caused by increased activity of the cell wall-loosening enzymes (polygalacturonase and cellulase) as well as by higher levels of lipid peroxidation in the final maturation stages. In general, physiological differences between maturation stages were observed and can largely explain the different detachment forces required at different stages. In conclusion, there is no clear abscission zone between the peduncle and the coffee fruit cv. “Icatu amarelo”. Nevertheless, the decrease in the detachment force throughout the maturation process can occur due to the activity of cell wall-degrading enzymes together with increased oxidative stress during the fruit ripening.

Resumo em Português:

RESUMO O estudo das associações lineares existentes entre caracteres é fundamental para a seleção ou quantificação indireta de caracteres de interesse. Assim, o objetivo deste trabalho foi avaliar as relações lineares entre caracteres de frutos de maçã das cultivares ‘Royal Gala’ e ‘Fuji’, na colheita e após armazenamento refrigerado. Foram avaliados 120 frutos de ‘Royal Gala’ e 120 frutos de ‘Fuji’ na colheita e 120 frutos de ‘Royal Gala’ e 111 frutos de ‘Fuji’ após armazenamento refrigerado. Foram mensurados os caracteres morfológicos/produtivos (massa, diâmetro longitudinal e diâmetros transversais maior e menor) e os caracteres de qualidade (firmeza de polpa, sólidos solúveis totais, acidez titulável, teor de suco, produção de etileno e respiração). Em cada cultivar (‘Royal Gala’ e ‘Fuji’) e momento de avaliação (na colheita ou após armazenamento refrigerado), foram calculados os coeficientes de correlação linear de Pearson entre os pares de caracteres e a correlação canônica entre os grupos de caracteres morfológicos/produtivos e de qualidade. Na colheita, os frutos com maior massa apresentaram menor firmeza de polpa e maior teor de sólidos solúveis totais, independentemente da cultivar. Após o armazenamento refrigerado, os frutos com maior massa apresentaram maior teor de sólidos solúveis totais e menor respiração, independentemente da cultivar, e maior teor de suco na cultivar ‘Fuji’.

Resumo em Inglês:

ABSTRACT The study of linear associations between traits is critical for the selection or the indirect quantification of the interest traits. Thus, the objective of this research was to evaluate the linear relationships among traits of apple fruits, in ‘Royal Gala’ and ‘Fuji’ cultivars, at harvest and after cold storage. In this investigation, 120 fruits of ‘Royal Gala’ and 120 fruits of ‘Fuji’ at harvest and 120 fruits of ‘Royal Gala’ and 111 fruits of ‘Fuji’ after cold storage were evaluated. Morphological/productive (mass, longitudinal diameter, major and minor transverse diameters) and quality traits (firmness, total soluble solids, titratable acidity, juice content, ethylene production and respiration) were measured. In each cultivar (‘Royal Gala’ and ‘Fuji’) and time of evaluation (at harvest or after cold storage), the Pearson’s linear correlation coefficients among the pairs of traits and the canonical correlation among the groups of morphological/productive and of quality traits were calculated. At harvest, the apple fruits with higher mass had lower firmness and higher total soluble solids, regardless of the cultivar. After cold storage, the apple fruits with higher mass had higher total soluble solids and lower respiration, regardless of the cultivar, and higher juice content in the ‘Fuji’ cultivar.

Resumo em Português:

RESUMO O presente trabalho objetivou estimar a divergência genética entre progênies de meios-irmãos de milho visando direcionar a recombinação entre progênies contrastantes e superiores para a produção de milho-verde. Noventa e seis progênies foram avaliadas no delineamento de blocos casualizados com 3 repetições, sendo mensuradas 18 características associadas à adaptação agronômica e ao rendimento de milho-verde. A divergência genética foi estimada a partir da distância quadrada generalizada de Mahalanobis e as progênies agrupadas pelos métodos UPGMA e de Tocher. A análise de variância conjunta evidenciou variabilidade genética entre as progênies para as características. O método UPGMA foi mais sensível que o de Tocher, pois levou à formação de 11 grupos geneticamente dissimilares em comparação com os 5 de Tocher. O agrupamento identificou progênies superiores e contrastantes para a produção de milho-verde. A recombinação dessas progênies possibilitará incrementar a variabilidade genética e a frequência de alelos favoráveis à produção de milho-verde.

Resumo em Inglês:

ABSTRACT The present study aimed to estimate the genetic divergence among corn half-sib progenies seeking to direct recombination between contrasting and superior progenies for green corn production. Ninety-six progenies were evaluated in a randomized block design with 3 replications, and 18 characteristics associated with agronomic adaptation and green corn yield were measured. The genetic divergence was estimated using generalized square Mahalanobis distance and the progenies grouped by UPGMA and Tocher’s methods. The joint analysis of variance showed genetic variability among the progenies for the characteristics evaluated. The UPGMA method was more sensitive than Tocher’s, since it led to the formation of 11 groups genetically dissimilar compared to the 5 ones of Tocher’s method. The grouping allowed to identify superior and contrasting progenies for green corn production. The recombination of these progenies allows increasing genetic variability and the frequency of alleles favorable to the green corn production.

Resumo em Português:

RESUMO Estudos precoces com relação à seleção de linhagens de milho, com base em características de qualidade de sementes, podem ser explorados em programas de melhoramento nas primeiras etapas da obtenção de híbridos. O objetivo deste estudo foi analisar a divergência genética e a heterose associadas à qualidade fisiológica de sementes, em função do vigor, para a composição bioquímica na obtenção de milho híbrido. No experimento, foram utilizadas sementes de 8 linhagens e 3 híbridos de milho (híbrido simples, triplo e triplo modificado). Avaliaram-se os componentes bioquímicos nas sementes por meio dos teores de amido, proteína total, fósforo total, ferro e zinco. Com base no método de Singh, observou-se que a variável que mais contribuiu para a divergência genética quanto à composição bioquímica das sementes foi o teor de amido, com 46,47%. Constatou-se divergência genética e heterose para a composição bioquímica das sementes, indicando que essa característica pode ser explorada em programas de melhoramento visando à qualidade das sementes. O híbrido simples, composto pelas linhagens 2 e 4, foi indicado como a melhor combinação para a composição bioquímica nas sementes, com as maiores heteroses para os teores de amido, fósforo, ferro e zinco.

Resumo em Inglês:

ABSTRACT Early studies with regard to the selection of maize lines based on seed quality characteristics can be exploited in breeding programs in the early stages of hybrids achievement. The objective of this study was to analyze the genetic diversity and the heterosis associated with physiological quality of seeds, in function of the force, for biochemical composition in the achievement of hybrid corn. In the experiment, seeds from 8 lines and 3 maize hybrids (single hybrid, triple and modified triple) were used. Biochemical components in the seeds were evaluated by means of starch content, total protein, total phosphorus, iron and zinc. Based on Singh’s method, it was observed that the variable which most contributed to genetic divergence on the biochemical composition of the seeds was the starch content, with 46.47%. Genetic diversity and heterosis were found for the biochemical composition of the seeds, indicating that this feature can be exploited in breeding programs aiming at the quality of the seeds. The simple hybrid, composed of the strains 2 and 4, was indicated as the best match for the biochemical composition in seeds, with the highest heterosis for starch content, phosphorus, iron and zinc.

Resumo em Inglês:

Abstract Guava plays an important role in Brazilian agribusiness. Among other goals, guava breeding programs aim to achieve more productive cultivars and improved fruit quality. Thus, the present study aimed to investigate genetic variability in full-sib progenies of Psidium guajava (guava) and estimate the genetic progress obtained from different selection criteria in order to select the most promising genotypes. This is the first work that uses these criteria of selection to guava. The experiment was conducted in randomized block design with 2 replicates, and 10 progenies were assessed, with 12 plants per plot. Direct and indirect selection and the classic index with 2 economic weights were used for predicting the genetic gain between and within progenies. The 5 best progenies among those analyzed and 4 plants within the progenies were selected. Direct selection provided higher gains for number of fruits, and indirect selection generated small gains for the other traits. When the trial values were used as economic weight, the classic index was the selection criterion that showed the best results for gains in fruit number and fruit weight, being indicated as the most appropriate selection strategy for genetic breeding in the studied population.

Resumo em Inglês:

ABSTRACT Drought stress affects crop quality and productivity. The challenge of increasing food availability for a growing worldwide demand relies on the development of tolerant cultivars that will need to be adapted to arid and semi-arid areas. In order to help the understanding of rice response to stress, the phenotypic response of 6 Brazilian rice cultivars and 2 different crosses between them were characterized under drought conditions. Since gene regulation is an important part of root morphological responses to stressful conditions, 4 genes related to auxin response and root modifications (OsGNOM1 CRL4, OsIAA1, OsCAND1 and OsRAA1) were evaluated. The expression of these genes was analyzed in stressed rice using public available microarray data and then through real-time quantitative polymerase chain reaction (RT-qPCR), in the 6 phenotypically evaluated Brazilian genotypes under standard conditions (absence of stress). Our results show that all genotypes lengthened its roots in response to drought, specially the 2 hybrids. The expression of these genes is modified in response to stress, and OsRAA1 has a very special behavior, constituting a target for future studies. Further steps include the study of polymorphisms in these genotypes in order to understand if differences in these genes or in regulatory regions can be associated with differences in root system architecture and/or stress tolerance.

Resumo em Português:

RESUMO O objetivo do trabalho foi avaliar a competitividade relativa de cultivares de soja com o capim-arroz, com base em caraterísticas morfofisiológicas das espécies. Os experimentos foram conduzidos em delineamento experimental inteiramente casualizado, com 4 repetições. No primeiro estudo, tanto para soja quanto para capim-arroz, determinou-se a população de plantas em que a matéria seca da parte aérea tornou-se constante e independente da população (16 plantas∙vaso−1 ou 400 plantas∙m−2). No segundo estudo, foram conduzidos 2 experimentos para avaliar a competitividade dos cultivares de soja BMX Apolo RR e BMX Potência RR com plantas de capim-arroz, ambos conduzidos em série de substituição, sob diferentes proporções de plantas∙vaso−1 (100:0; 75:25; 50:50; 25:75 e 0:100) entre a cultura e a planta daninha. A análise da competitividade foi efetuada por meio de diagramas aplicados a experimentos substitutivos e uso de índices de competitividade relativa. Aos 44 dias após a emergência das espécies, efetuou-se a aferição dos parâmetros fisiológicos e morfológicos da cultura e planta daninha. Os cultivares de soja BMX Apolo RR e BMX Potência RR apresentam similaridade quanto à competição com o capim-arroz, de modo que a habilidade de uma espécie em interferir sobre a outra é equivalente. Para a estatura de plantas, o capim-arroz apresenta superioridade competitiva em relação ao cultivar de soja BMX Apolo RR, de ciclo superprecoce e porte baixo. A competição intraespecífica é mais importante para o capim-arroz do que a competição interespecífica com os cultivares de soja, resultando em efeitos negativos sobre características morfofisiológicas da espécie.

Resumo em Inglês:

ABSTRACT The aim of this work was to evaluate the competitiveness between soybean cultivars and barnyardgrass, based on morphological and physiological characteristics of species. The experiments were conducted in completely randomized experimental design, with 4 replications. In the first study, for both soybean and barnyardgrass, it was determined the population of plants in which shoot dry matter became constant and independent of the population (16 plants∙pot−1 or 400 plants∙m−2). In the second study, 2 experiments were conducted to evaluate the competitiveness of BMX Apolo RR and BMX Potência RR soybean cultivars with barnyardgrass plants, both carried out in replacement series under different proportions of plants∙pot−1 (100:0; 75:25; 50:50; 25:75 and 0:100) between the crop and the weed. The analysis of the species competitiveness was determined through diagrams applied to replacement series experiments and use of relative competitiveness indexes. At 44 days after the emergence of species, the physiological and morphological parameters of the crop and the weed were evaluated. The BMX Apolo RR and BMX Potência RR soybean cultivars show similar competitiveness when competing with the barnyardgrass; therefore, the ability of one species to interfere on another is equivalent. For plant height, barnyardgrass displays higher competitiveness compared to BMX Apolo RR, with early cycle and short height. The intraspecific competition is more important to barnyardgrass than interspecific competition with soybean cultivars, resulting in negative effects on the morphological and physiological characteristics of species.

Resumo em Português:

RESUMO Houve mudança na genética da soja cultivada na região Sul do Brasil a partir dos anos 2000, o que demanda investimento em estudos básicos e detalhados do crescimento e desenvolvimento. O objetivo deste estudo foi caracterizar a duração do período de sobreposição das fases vegetativa e reprodutiva, o crescimento em estatura e a emissão de nós após o início do florescimento em cultivares de tipo de crescimento determinado e indeterminado semeadas em diferentes épocas e regiões produtoras de soja no Rio Grande do Sul. Experimentos de campo foram conduzidos durante os anos agrícolas de 2012/2013 e 2013/2014, em Santa Maria, Itaqui, Frederico Westphalen, Capão do Leão, Júlio de Castilhos e em 3 lavouras comerciais de soja em Restinga Sêca, Tupanciretã e Água Santa. Foram estimadas a sobreposição (em dias) das fases vegetativa e reprodutiva, diferença do número de nós e da estatura em R8 e R1. As cultivares com tipo de crescimento indeterminado apresentaram maior período de sobreposição das fases vegetativa e reprodutiva, crescimento em estatura e emissão de nós após o início do florescimento em comparação com as cultivares determinadas. A magnitude dos valores de sobreposição das fases vegetativa e reprodutiva e do aumento em estatura e número de nós após o R1 variaram com o tipo de crescimento, grupo de maturidade relativa, local e época de semeadura.

Resumo em Inglês:

ABSTRACT There was a change in the genetics of soybeans grown in southern Brazil from the 2000s, which requires investment in basic and detailed studies about growth and development. The purpose in this paper was to characterize the overlap period of vegetative and reproductive phases, growth in height and the emission of nodes after the beginning of flowering in determinate and indeterminate cultivars in different sowing dates and soybean regions in Rio Grande do Sul. Field experiments were conducted during the growing seasons of 2012/2013 and 2013/2014, in Santa Maria, Itaqui, Frederico Westphalen, Capão do Leão, Júlio de Castilhos and in 3 commercial soybean crops in Restinga Sêca, Tupanciretã and Água Santa. Overlap determination (in days) of vegetative and reproductive phases, difference in the number of nodes and height in R8 and R1 were estimated. The cultivars with indeterminate growth had higher overlap period of vegetative and reproductive phases, height growth and emission of nodes after the beginning of flowering in comparison with the determinate cultivars. The magnitude of the overlap values of vegetative and reproductive phases and of the increase in height and number of nodes after R1 ranged with the type of growth, maturity group, location, and sowing date.

Resumo em Inglês:

ABSTRACT Soil sampling is an important stage of digital soil mapping. The objective of this study was to characterize the spatial design of soil sampling using soil apparent electrical conductivity (ECa) and its optimized spatial sampling. For the characterization, it was used the Spatial Simulated Annealing (SSA) technique, incorporated on the software SANOS 0.1, and the method of response surface sampling design on the software ESAP 2.35. The ECa was measured at 1,887 points in an area of 6 ha located in the northwestern region of Spain. The EM38-DD equipment (Geonics Limited 2005) was used at 2 depths: vertical dipole (1.5 m effective measurement depth) and horizontal dipole (0.75 m effective measurement depth). Semivariogram showed trend for ECa in vertical dipole (ECa-V) and ECa in horizontal dipole (ECa-H). Software SANOS 0.1 and ESAP 2.35 were used to obtain the 40-point sampling scheme, using the 2 schemes (SANOS and ESAP). ECa-V estimation values at the 1,887 points were calculated with residual ordinary kriging. The sampling scheme obtained from ESAP was better than with SANOS.

Resumo em Português:

RESUMO Objetivou-se neste trabalho verificar alterações morfológicas e anatômicas no sistema radicular do girassol, bem como nos seus atributos produtivos em função da compactação adicional provocada pelo tráfego de trator em um Latossolo Vermelho distrófico típico. A pesquisa foi realizada a campo, sendo os tratamentos referentes a 5 níveis de compactação: sem tráfego adicional (C0); 1 (C1); 3 (C3); 6 (C6) e 11 (C11) passadas de trator. Foram avaliadas as propriedades físicas do solo e a distribuição das raízes nas camadas de 0 – 0,05; 0,05 – 0,10; 0,10 – 0,15 e 0,15 – 0,20 m de profundidade, além das características vegetativas e reprodutivas e as alterações anatômicas das raízes. A compactação do solo pelo tráfego de máquinas promove diminuição do índice de área radicular (IAR) do girassol. A distribuição das raízes do girassol ocorre de forma superficial no perfil do solo e foi diminuída pela metade quando submetida à C11. A compactação do solo proporcionou modificações anatômicas nas raízes, com alteração do diâmetro de vasos, aparecimento de células xilemáticas angulosas, esmagamento do câmbio vascular e surgimento de aerênquimas, típico em raízes submetidas a hipóxia. As plantas apresentaram menores altura, altura de capítulo, diâmetro da haste, produtividade e massa de aquênios, havendo redução na população. Verificou-se a correlação linear negativa entre produtividade e resistência do solo à penetração, sendo 0,733 MPa considerado como valor crítico, e correlação linear positiva entre macroporosidade e IAR, sendo 0,264 m3∙m−3 considerado como valor crítico.

Resumo em Inglês:

ABSTRACT The aim of this research was to verify morphologic and anatomic changes in the root system of the sunflower as well as in its productive attributes in function of the additional compression caused by tractor traffic in a typical Kandiustox (Oxisol). The research was conducted in the field, in 5 levels of compression: without additional traffic (C0); 1 (C1); 3 (C3); 6 (C6) and 11 (C11) paths of tractor. The physical properties of the soil and the distribution of the roots in the layers 0 – 0.05; 0.05 – 0.10; 0.10 – 0.15 and 0.15 – 0.20 m of depth were evaluated, besides the vegetal and reproductive characteristics and the anatomic changes in the roots. The soil compression by the machine traffic results in the reduction in the root area index (RAI) of the sunflower. The distribution of the sunflower’s roots occurs superficially in the soil’s profile and was reduced by a half when submitted to C11. The soil compression resulted in anatomic alterations in the roots, with changes in the diameter of the ducts, emerging of angle xilematic cells, crushing in the vascular cambium and occurrence of aerenchyma, typical in roots submitted to hypoxia. The plants presented less height, flower height, stem diameter, productivity and achenes mass, occurring a reduction in plant population. It was verified negative linear correlation between productivity and soil resistance to penetration, being 0.733 MPa a critical value, and positive linear correlation between macroporosity and RAI, with 0.264 m3∙m−3 considered as a critical value.

Resumo em Português:

RESUMO Objetivou-se, com esse estudo, verificar a cinética de sorção e dessorção de diuron em um Latossolo Vermelho-Amarelo sob aplicação de biochar. As amostras foram coletadas em um experimento conduzido a campo em delineamento de blocos ao acaso composto pela combinação de 2 níveis de adubação de base (0 e 400 kg∙ha−1 da fórmula 00-20-20 de fertilizante NPK) e 3 doses de biochar (0, 8 e 16 Mg∙ha−1). Na avaliação da sorção e dessorção, utilizou-se o método Batch Equilibrium. Foi avaliada a cinética de sorção e dessorção de diuron, bem como carbono orgânico total, teores de ácido fúlvico, ácido húmico e humina, pH e coeficiente de partição ao carbono orgânico. A isoterma de Freundlich ajustou-se adequadamente para descrever a cinética de sorção do diuron em todos os tratamentos estudados. A aplicação de biochar proporcionou aumento da sorção (Kf) e redução da dessorção de diuron em 64 e 44%, respectivamente. Esse efeito é atribuído à contribuição do biochar para os teores de carbono orgânico total e C-humina e destes para o diuron por meio de interações hidrofóbicas e pontes de hidrogênio. A correlação positiva entre o coeficiente de partição ao carbono orgânico e o Kf confirma a importância do compartimento orgânico do solo na sorção de diuron. Não se verificou competição do fertilizante NPK pelo mesmo sítio de sorção do diuron. O aumento da sorção e a redução da dessorção revelam que a aplicação de biochar é uma importante alternativa para a remediação da lixiviação de diuron no solo, sobretudo, em solos arenosos.

Resumo em Inglês:

ABSTRACT The objective of this study was to verify the kinetics of sorption and desorption of diuron in an Oxisol under application of biochar. The samples were collected in a field experiment conducted in randomized design blocks consisted of 2 base fertilization levels (0 and 400 kg∙ha−1 NPK 00-20-20 fertilizer formula) and 3 doses of biochar (0, 8 and 16 Mg∙ha−1). In the evaluation of sorption and desorption, Batch Equilibrium method was used. The kinetics of sorption and desorption of diuron, total organic carbon, fulvic acid, humic acid and humin, pH and partition coefficient to organic carbon were evaluated. The Freundlich isotherm was adjusted appropriately to describe diuron sorption kinetics in all the studied treatments. The application of biochar provided increment in the sorption (Kf) and reduction in the desorption of diuron in 64 and 44%, respectively. This effect is attributed to the biochar contribution to the total organic carbon and C-humin and of these to diuron through hydrophobic interactions and hydrogen bonds. The positive correlation between the partition coefficient to organic carbon and Kf confirms the importance of soil organic compartment in the sorption of diuron. There was no competition of NPK fertilizer for the same sorption site of diuron. The increase and reduction in sorption and desorption, respectively, show that the application of biochar is an important alternative for the remediation of soil leaching of diuron, especially in sandy soils.

Resumo em Português:

RESUMO O cultivo de diferentes espécies de plantas de cobertura possibilita a melhoria e a conservação do solo e da matéria orgânica, além de promover consideráveis aumentos de rendimento nas culturas subsequentes, com significativos ganhos econômicos. Objetivou-se avaliar o crescimento e produtividade de milho-verde sobre diferentes coberturas de solo no sistema plantio direto (SPD) orgânico. O trabalho foi disposto em delineamento de blocos casualizados, com 6 repetições e 5 sistemas de produção, constituídos por 3 coberturas de solo no SPD orgânico, com palha de aveia-preta, palha de tremoço-branco e palha do consórcio aveia-preta/tremoço-branco, assim como 2 sistemas sem palhada e com revolvimento do solo, um orgânico e outro convencional. Foram realizadas avaliações de diâmetro do colmo, de altura de planta e da inserção de espiga, nos estádios V5, V10 e R3, número total de espigas comerciais, produtividade total de espigas com palha e sem palha, peso médio de espigas com palha e sem palha, produtividade, peso médio e percentual de espigas comerciais, comprimento e diâmetro de espigas comerciais sem palha. O SPD orgânico sobre a palha de tremoço-branco em solteiro e em consórcio com aveia-preta proporcionou maior crescimento das plantas de milho nos estádios inicias da cultura. O uso de tremoço-branco solteiro ou em consórcio com aveia-preta apresentou-se como boa opção para formação de palha no SPD orgânico, garantindo crescimento e produtividade satisfatórios para a cultura do milho-verde.

Resumo em Inglês:

ABSTRACT The cultivation of different species of cover crops enables the improvement and conservation of soil and organic matter, in addition to promoting significant yield increases in subsequent crops, with significant economic gains. The objective of this study was to evaluate the growth and productivity of green corn on different soil covers in an organic no-tillage system. The work used a randomized block design, with 6 repetitions and 5 treatments, consisting of 3 soil covers in an organic no-tillage system, with black oat straw, white lupine straw and straw of the intercropping oat/lupine, as well as 2 systems without straw and with revolved soil, an organic one and a conventional. Evaluations of culm diameter, plant height and insertion of the corn ears were carried out, at stages V5, V10 and R3, as well as of total number of marketable ears, the total productivity of ears with and without straw, average weight of ears with and without straw, productivity, average weight and percentage of marketable ears, length and diameter of marketable ears without straw. The organic no-tillage system on the white lupine straw in single and intercropped with black oat provided greater growth of corn plants at the early stages of culture. The use of white lupine single or intercropped with black oat showed itself as good option for straw training in an organic no-tillage system, ensuring satisfactory growth and productivity for the green corn crop.

Resumo em Inglês:

ABSTRACT The need to use a length of rainfall records of at least 30 years to calculate the Standardized Precipitation Index (SPI) limits its application in several Drought Early Warning Systems of developing countries. Therefore, in order to increase the number of weather stations in which the SPI may be applied, this study quantified the difference among SPI values derived from calibration periods (CP) smaller than 30 years in respect to those computed from the 30-year period of 1985 – 2014 in the State of São Paulo, Brazil (time scales ranging from 1 to 12 months were considered). The correlation, agreement and consistency of SPI values derived from CP ranging from the last 30 to 21 years have been evaluated. The Kolmogorov-Smirnov/Lilliefors test indicated, for all CP, that the 2-parameter gamma distribution may be used to calculate the SPI in the State of São Paulo. The normality test indicated that, even for the period of 1985 – 2014, the normally assumption of the SPI series is not always met. However, it was observed no remarkable difference in the rejection rates of the normality assumption obtained from the different CP. Finally, both absolute mean error and the modified index of agreement indicated a high consistence among SPI values derived from the calibration period of 1991 – 2014 (24 years) in respect to those derived from the 30-year period. Accordingly, it is possible to use weather stations with rainfall records starting in 1991 (or earlier) to calculate, in operational mode, the SPI in the State of São Paulo.