Carlos Sigueyuki Sediyama

Modelagem da recomendação de corretivos e fertilizantes para a cultura da soja

A recomendacao de adubacao para as culturas agricolas, no Brasil, e feita com base em tabelas que relacionam a classe de disponibilidade do nutriente no solo com a dose a ser aplicada. Este trabalho apresenta uma alternativa para recomendar corretivos e fertilizantes para a cultura da soja, o SIRSo (sistema de recomendacao de corretivos e fertilizantes para a cultura da soja). O principio desse sistema e o balanco nutricional, ou seja, a recomendacao se faz a partir da diferenca entre o requerimento de nutrientes pela planta e o suprimento de nutrientes pelo solo, por residuos orgânicos, por fertilizantes e pela calagem. O sistema considera ainda o fator sustentabilidade, visando manter uma quantidade de nutriente no solo capaz de garantir produtividade minima em cultivos subsequentes. Para recomendar calagem, o sistema considera dois metodos: a neutralizacao do Al3+ e a elevacao dos teores de Ca2+ + Mg2+, ou a saturacao por bases. O requerimento de nutrientes varia com a produtividade esperada de graos, com as caracteristicas do solo e com a taxa de recuperacao pela planta do nutriente aplicado ao solo. O suprimento pelo solo depende da disponibilidade do nutriente, estimada a partir da analise de solo e da taxa de recuperacao pelo extrator do nutriente aplicado. As comparacoes entre as recomendacoes geradas pelo SIRSo e aquelas oriundas das tabelas em uso no Pais mostram, em geral, que o SIRSo recomenda maior quantidade de nutrientes, principalmente de P e K quando consideradas as maiores produtividades, fato confirmado pela analise de sensibilidade, que mostrou grande variacao da dose a ser recomendada desses nutrientes com a produtividade de graos. Esse fato pode ser considerado como vantagem do SIRSo em relacao as tabelas, muitas das quais apresentam pouca ou nenhuma variabilidade das doses em relacao a produtividade.

Resposta da produtividade de grãos e outras características agronômicas do trigo EMBRAPA-22 irrigado ao nitrogênio em cobertura

As doses e a epoca de aplicacao do nitrogenio (N) podem influenciar as caracteristicas agronomicas do trigo (Triticum aestivum L.) irrigado e, consequentemente, a produtividade de graos. Neste sentido, foram instalados dois experimentos na Estacao Experimental da Universidade Federal de Vicosa, localizada em Coimbra (MG), em 1995 e 1996. Os tratamentos foram constituidos pela combinacao de quatro doses de N (30, 60, 90 e 120 kg ha-1), quatro formas de parcelamento (dose total aos 20 dias da emergencia (DAE); ½ aos 20 + ½ aos 40 DAE; 1/3 aos 20 + 2/3 aos 40 DAE e 2/3 aos 20 + 1/3 aos 40 DAE) e uma testemunha (sem N em cobertura), dispostos em esquema fatorial 4 x 4 + 1, no delineamento em blocos casualizados com quatro repeticoes. A altura e o acamamento das plantas, a biomassa seca, o indice de colheita, a massa de mil graos, o peso hectolitrico e a produtividade de graos foram influenciados pelas doses de N. Em 1996, o numero de espigas por metro quadrado e o numero de perfilhos ferteis por planta diminuiram, em consequencia do acamamento precoce das plantas, enquanto o numero de graos por espiga e o numero de graos por metro quadrado aumentaram com o incremento nas doses de N. As formas de parcelamento influenciaram somente o acamamento das plantas.

Correlation between high molecular weight gluten subunits composition and bread-making quality in Brazilian wheat

Bread-making quality is one of the most important targets in the genetic improvement of wheat. Although extensive analyses of quality traits such as farinography, sodium dodecyl sulfate (SDS) sedimentation, alveography, and baking are made in breeding programs, these analyses require high amounts of seeds which are obtained only in late generations. In this experiment the statistical correlations between the high molecular weight subunit of glutenin and bread-making quality measured by alveograph, farinograph and SDS sedimentation were evaluated. Seventeen wheat genotypes were grown under the same conditions, each producing about 1 kg of seeds for the evaluations. The high molecular weight (HMW) glutenin subunits were analyzed by SDS-PAGE. Statistical correlations were highly significant between HMW glutenin subunits and alveograph and SDS sedimentation. These results indicate the possibility of manipulating major genes for wheat seed quality by coupling traditional breeding with non-destructive single seed analysis. Only half seed is necessary to perform the SDS-PAGE analysis. Therefore, the other half seed can be planted to generate the progeny. Seed yield and SDS sedimentation were statistically correlated, indicating the possibility of simultaneous selection for both traits

Resposta do tomateiro à fertirrigação potássica e cobertura plástica do solo

The aim of this work was to determine the effects of fertirrigation with potassium and black polyethylene cover on tomato. A field experiment was carried out on a cambic yellowish podzolic at the Universidade Federal de Vicosa, in Vicosa, MG, Brazil. The treatments, with five replicates, following a randomized block design, were: (A) manual application of 40% of recommended K rate at the seedling transplantation row and manual sidedress application of 60%; (B) manual application of 40% of recommended K rate at the seedling transplantation row and 60% by fertirrigation; (C) similar procedure to B but with black polyethylene cover; (D) application of 100% of K rate by fertirrigation and (E) similar procedure to D but with black polyethylene cover. Treatments B, C, D and E were drip irrigated. Tomato yields were higher with K application by fertirrigation than using the manual fertilization method, but the tomato yields were not influenced by K partial or total fertirrigation neither by black polyethylene cover. The NO3-N, organic-N, K, Ca and Mg concentrations on leave petioles were not influenced by treatments.

Padrão de herança e critérios de seleção para resistência às raças 3 e 9 do nematóide-de-cisto-da-soja

The objective of this work was to determine soybean resistance inheritance to Heterodera glycines Ichinohe (soybean cyst nematode - SCN) races 3 and 9, as well as to evaluate the efficiency of direct and indirect selection in a soybean population of 112 recombinant inbred lines (RIL) derived from the resistant cultivar Hartwig. The experiment was conducted in a completely randomized design, in Londrina, PR, Brazil. The estimated narrow-sense heritabilities for resistance to races 3 and 9 were 80.67 and 77.97%. The genetic correlation coefficient (rg = 0.17; p<0.01) shows that some genetic components of resistance to these two races are inherited together. The greatest genetic gain by indirect selection was obtained to race 9, selecting to race 3 due to simpler inheritance of resistance to race 9 and not because these two races share common resistance genes. The resistance of cultivar Hartwig to races 3 and 9 is determined by 4 and 2 genes, respectively. One of these genes confers resistance to both races, explaining a fraction of the significant genetic correlation found between resistance to these SCN races. The inheritance pattern described indicates that selection for resistance to SCN must be performed for each race individually.

Reação de genótipos de soja à infecção natural por ferrugem asiática

The objective of this work was to evaluate the progress of Asian soybean rust (Phakopsora pachyrhizi) on Brazilian soybean genotypes destined for silage production, under natural conditions of infection. Rust severity over time and combining ability of five cultivars and 20 F3 soybean progenies were evaluated. The largest area under rust progress curve (AURPC) was 2,116 for progenies from the cross between cultivars UFVS 2003 x UFV16, and the smallest was 1,307 for UFV16 x Tucunare. The effects of the general and specific combining abilities for AURPC were significant between the parents and progenies, as well as for the reciprocal crosses. These results indicate that resistance to Asian soybean rust can be influenced by maternal components.

Controle químico de plantas daninhas em cultivos sucessivos de milho e feijão

This trial was carried out at the Sooretama Experimental Farm, in Linhares, State of Espirito Santo, Brazil, in order to evaluate the efficiency of herbicides on weed control in sucessive crops of corn and beans. The comercial mixture of atrazine plus metolachlor was more efficient to control weeds in corn (Zea mays) crop than atrazine and metolachlor applied alone. The comercial rate of 8,04 l ha-1 led to the highest yield of corn (7004,92 kg ha-1). The tank mixture of fomesafen plus sethoxydim was more efficient to control weeds in the field bean (Phaseolus vulgaris) crop than linuron and metolachlor applied alone. The tank mixture of 0,74 l ha-1 of fomesafen plus 0,74 l ha-1 of sethoxydim showed the highest yield of bean (1454,05 kg ha-1).

Efeitos de dejeto de suínos na incidência de plantas daninhas e na eficiência do herbicida metribuzin na cultura da batata-doce

O experimento foi realizado em condicoes de campo, na Fazenda Experimental da EPAMIG, em Ponte Nova-MG, no periodo de janeiro a julho de 1995, com o objetivo de avaliar o efeito de doses de dejeto de suinos na forma liquida, sobre a producao de batata-doce, cultivar Paulista, na incidencia de plantas daninhas e na eficiencia de controle de especies de plantas daninhas pelo metribuzin. Utilizou-se o delineamento em blocos ao acaso, no esquema fatorial, com quatro repeticoes. Foram avaliados os efeitos das doses 0, 20, 40 e 60 m3 ha-1 de dejeto de suinos combinadas com 0, 300, 600 e 900 g ha-1 de metribuzin. Houve incremento linear de biomassa fresca das plantas daninhas de folhas largas, plantas de folhas estreitas e total de plantas daninhas em funcao do aumento das doses dejeto de suinos. O metribuzin foi seletivo para a cultura de batata-doce, nao sendo observado nenhum sintoma visivel de fitotoxicidade a cultura e eficiente no controle das principais plantas daninhas presentes na area. A producao maxima de raizes comerciais (22,94 t ha-1) foi obtida com o metribuzin na dose 810,17 g ha-1. Isto representou cerca de 89% superior ao peso obtido pela testemunha sem tratos culturais. Esta produtividade foi semelhante aquela observada nos tratamentos que receberam tres cultivos. As plantas daninhas interferiram negativamente nas principais caracteristicas avaliadas de producao da batata-doce. A cultura da batata-doce respondeu positivamente a adubacao com dejeto liquido de suinos, com aumento linear da producao de raizes das classes extra A, comercial e total. Verificou-se tambem que houve correlacao negativa entre plantas daninhas e as principais caracteristicas de producao da cultura de batata-doce.

QUALIDADE SANITÁRIA E PRODUÇÃO DE ALDEÍDOS TOTAIS EM SEMENTES DE SOJA SEM LIPOXIGENASES 1

This work was carried out to evaluate the effect of seed lipoxygenases genetic elimination on the sanitary quality and aldehyde production of the seeds of four soybean varieties, harvested at different periods. Seeds of CAC-1, Doko-RC, UFV-16 and Cristalina varieties and their respective lines with absence of the three lipoxygenases, called triple-null, were multiplied in the field and harvested at the R8 stage and 15, 30 and 45 days later. The seeds were submitted to the blotter test and to the evaluation of total aldehyde content by the MBTH method. It was concluded that the most frequent fungi were Fusarium spp., Phomopsis spp. and Cercospora kikuchii. The frequency of total fungi increased with harvest delaying. The harvest delaying increased the production of aldehyde in the seeds of Cristalina with and without lipoxygenases, of CAC-1 with lipoxygenases and of Doko RC without lipoxygenases, while in the seeds of the remaining genotypes, the aldehyde production was minimum in all harvesting times. The genetic elimination of lipoxygenases from the seeds did not affect the fungi incidence or the aldehyde production.

Qualidade fisiológica de sementes de linhagens de soja com presença ou ausência de lipoxigenases, em diferentes épocas de colheita

Soybean consumption as food is still limited due to its characteristic flavor and odor that have as the main cause the lipoxygenases enzymes. To avoid this problem, the Soybean Genetic Improvement Program of the Federal University of Vicosa developed lines with the absence of the three forms of lipoxygenases in the grains. The present work was performed to evaluate the effect of the genetic elimination of lipoxygenases on physiological seed quality of four varieties, harvested at different periods. Seeds of CAC-1, Doko-RC, UFV-16 and Cristalina varieties and their respective derived lines with absence of three lipoxygenases, called triple-null, were multiplied in the field and the seeds were harvested at the R8 stage and 15, 30 and 45 days after the first harvest. Later, the seeds were submitted to the germination test, first germination counting test, sand bed germination, accelerated aging and seedling emergence. It was observed that the fourth harvesting time showed highest differences among varieties and materials with or without lipoxygenases. It was concluded that the introduction of genes that condition the absence of the three lipoxygenases in the seeds, in the four varieties, produced lines of soybean with seeds of equal or poorer physiological quality, than that of the original varieties, depending on the studied variety, indicating a lack of direct relation between physiological quality and presence of lipoxygenases in the seeds.