Edésio Fialho dos Reis

ATRIBUTOS FÍSICOS, QUÍMICOS E BIOLÓGICOS DE SOLO DE CERRADO SOB DIFERENTES SISTEMAS DE USO E MANEJO

As knowledge on no-till system expands, it has become quite clear that separate chemical indicators cannot provide a detailed soil characterization. The objective of this study was to evaluate the effects of tillage systems and soil use in the physical, chemical and biological properties of a clayey dystrophic Red Latosol - Oxisol and a sandy Neosol - Entisol. The treatments for the Oxisol consisted of: native savanna, pasture, conventional tillage, no-tillage with turnip and with forage sorghum as cover crop. For the Entisol: native savanna, native pasture, integrated crop-livestock, cultivated pasture, no-tillage with soybean and corn in the summer. Soil samples were collected from a depth of 0-10 cm, in a clayey dystrophic Red Latosol - Oxisol and a sandy Neosol - Entisol in a savanna ecosystem, near the Parque Nacional das Emas. Treatments were arranged in a completely randomized design, in 5 plots of 150m2, where 10 sub-samples were collected randomly. Chemical, physical and biological analyses were carried out at a soil laboratory. In the Entisol, tillage influenced the soil density, total pore volume, macroporosity and penetration resistance. In the Oxisol, tillage induced variations in soil bulk density, macroporosity and penetration resistance. Small variations in chemical properties were observed in both soils, with higher potential acidity and lower exchangeable cation and phosphorus concentrations. The soil biological properties were influenced by tillage, and were most affected in systems with more anthropic action. In the canonical data analysis the greater weighting coefficient of the physical properties in the canonic variables demonstrated that these were the least important. The contribution of the separate soil properties to evaluate soil quality was minor, but the most sustainable management systems could be defined by multivariate analysis.

Comparação de procedimentos de seleção para produção de grãos em populações de soja

This study aimed to predict the genetic gain for grain production by applying different selection procedures and to choose, among the studied populations, the most promising one regarding gain expectation. Four selection strategies were used: selection among and within families; combined selection and individual selection for grain production; as well as for selection free from weights and parameters, number of days and plant height at maturation. Generation F5 individuals were selected, placed and observed in the field following the design standard-cultivars among the segregating lines, during the agricultural year of 1996/1997, in Vicosa, Minas Gerais. The results indicated that, considering the family in the selective process, combined selection was the most promising strategy. However, individual selection showed the highest expectation of genetic gain among the four strategies. The cross between the parents CEPS 89-26 and FT-Cristalina presented the highest expectation of genetic gain.

Atividade da enzima nitrato redutase em milho cultivado sob diferentes níveis de adubação nitrogenada e potássica

Because of the use in human feeding, animal, and high productive potential, corn is considered to be one of the most important cultivated and commercialized cereals in the world. The aim of this research was to evaluate the effect of different potassium doses and nitrogen in the activity of the enzyme nitrate reductase in the corn culture in a greenhouse environment. Five dosages of nitrogen (0; 50; 100; 150 and 200kg ha-1) and five potassium dosages (0; 40; 80; 120 and 160kg ha-1) were used. The activity of the nitrate reductase was esteemed, in vivo after the plants reached four leaves totally unfolded. The method that was used is based on the principle of the amount of nitrite liberated by fragments of alive tissue in a buffer in the presence of a permanent agent and substrate, reflects the potential in situ activity of the enzyme nitrate reductase. The activity of the enzyme nitrate reductase suffered significant influence of the f nitrogen and potassium dosage interaction, where the interaction N=100kg ha-1 and K=40kg ha-1 provided the best medium of the experiment. From this dosage on, the increase of nitrogen and potassium supplement caused a reduction of the enzymatic activity.

Effect of arbuscular mycorrhizal fungi and phosphate fertilization on initial growth of six arboreal species of cerrado

Conduziu-se este estudo, com o objetivo de avaliar o beneficio da inoculacao com o fungo micorrizico arbuscular, Glomus clarum, sobre o crescimento inicial da gabiroba (Campomanesia cambessedeana), baru (Dipterix alata), jatoba (Hymenaea courbaril), inga (Inga laurina), caroba (Jacaranda cuspidifolia) e chicha (Sterculia striata), especies arboreas nativas do Bioma de Cerrado, em solo nao esterilizado com baixo (0,02 mg L-1) e alto (0,2 mg L-1) teor de P na solucao do solo. Os experimentos foram conduzidos em casa de vegetacao, em vasos de 1,5 kg, por ate 120 dias. O delineamento experimental para cada especie arborea foi inteiramente casualizado com dez repeticoes, em esquema fatorial 2x2 (mudas inoculadas e nao inoculadas e dois niveis fosforo (P) na solucao do solo). As plantas arboreas do Cerrado apresentaram incremento na colonizacao micorrizica pela inoculacao com Glomus clarum, exceto o chicha que apresentou colonizacao da comunidade indigena alta nao diferindo da promovida pelo fungo inoculado. A inoculacao proporcionou aumento no crescimento do baru, gabiroba, inga, caroba e chicha, assim como da materia seca da parte aerea (MSPA) e a materia seca de raizes (MSR), sendo que, para a caroba, o efeito foi sinergico com a aplicacao de P ao solo. O baru e o jatoba apresentaram apenas incremento da materia seca com a aplicacao de P ao solo. A micotrofia (dependencia micorrizica) das especies e suas respostas a inoculacao e ao fosforo sao discutidas. Recomenda-se para producao de mudas, de qualidade, de caroba, gabiroba, chicha e inga a inoculacao com Glomus clarum conjuntamente com a fertilizacao fosfatada do solo e para o jatoba e baru apenas aplicacao de P ao solo.

Genetic divergence in pepper genotypes from southwest Goiás

Knowledge on the genetic diversity in genebanks is important for germplasm conservation and use in breeding programs, where it can reduce time and costs of breeding of new genotypes. The purpose of this study was to evaluate the genetic divergence among 137 genotypes of Capsicum chinense Jacq. by morphological descriptors and multivariate techniques, with a view to the identification of groups for promising crosses for breeding programs. The experiment was conducted in a greenhouse, arranged in a randomized complete block design with four replications, where each plot consisted of a pot with one plant. The 20 descriptors recommended by the International Plant Genetic Resources Institute - IPGRI were considered for the morphological characterization. By analysis of variance, significant differences between genotypes were detected for the studied descriptors. Clustering by the Tocher optimization method formed five groups, and by the hierarchical clustering method UPGMA, 11 groups. Based on larger distances intergroup, crosses are recommended among genotypes of the groups II x V, II x IV, and I x V for the Tocher method, and by UPGMA among genotypes of the groups VI x XI, II x XI, IV x XI,. The cophenetic correlation coefficient for the hierarchical clustering method UPGMA was 0.797 (p <0.01). The traits that contributed most to the total genetic diversity were number of days to flowering and plant height.

Efeito de diferentes tratamentos na superação da dormência de sementes da palmeira Syagrus oleracea Becc.

The Guariroba Palm (Syagrus oleraces Becc) is the only species known as producer of bitter palm heart, which is very appreciated in Goiânia cooking and can also be used in animal feeding and landscaping; however, it is little studied. The slow and uneven germination of seeds cause problems in the propagation of this species, thus complicating mainly the seedling production at a commercial scale. This study evaluated different treatments to reduce the dormancy state and consequently to speed up the germination period of guariroba palm seeds and looking for techniques of easy comprehension and application by small farmers. The experimental design was in completely randomized blocks with three replications in a 2 x 7 factorial arrangement; i.e, two levels for type of seeds (pulped and not pulped) an seven different methods of seed treatment. In the second stage, the interference of coleobroca in the seed germination was quantified by counting the number of attacked seeds after seedling germination. The observed results showed that treatments under low temperatures caused a significant decrease in seed germination of guariroba and that non pulped seeds reduced the time required for germination. It was also evidenced that reducing humidity to 8% does not affect the germination of guariroba seeds and that the water absorption by the seeds was influenced directly by the time of immersion in the water glass, independently of pulp presence. The studied treatments were not effective in reduccing coleobroca attack.

Absorção de fósforo em doze genótipos de milho inoculados com fungo micorrízico arbuscular em solo de cerrado

The aim of this research was to evaluate the efficiency of phosphorus absorvation in twelve corn genotypes. The study was performed in presence and absence of arbuscular mycorrhizal fungus inoculation. The experiment took place at the Agrarian and Biological Center greenhouse, in the Federal University of Goias, Jatai, Brazil. The genotypes were randomly distributed in blocks with three replicates in a 12x2x2 factorial. The genotypes were AG9010, P30K75, AG8060, P30P70, AG405, P30F33, AG7000, BANDEIRANTES, EMGOPA501, BALU178, DINA657, 2C599, cultivated under two doses of phosphorus (10 and 100mg kg-1 of P in soil solution) in presence or absence of Glomus etunicatum mycorrization. The study verified the difference among genotypes in dry root matter production. The ratio among root dry and shoot dry matter colonized with mycorrizal fungus was observed. Ratio accumulated phosphorus among shoot and dry root matter was also seen. The mycorrization changed classification of genotypes regarding to dry matter shoot production under low P and the response for higher P supply.

Detecção de fatores de virulência e de resistência antimicrobiana em isolados produtores de toxina Shiga de ovinos

In order to detect virulence factors in Shiga toxin-producing Escherichia coli (STEC) isolates and investigate the antimicrobial resistance profile, rectal swabs were collected from healthy sheep of the races Santa Ines and Dorper. Of the 115 E. coli isolates obtained, 78.3% (90/115) were characterized as STEC, of which 52.2% (47/90) carried stx1 gene, 33.3% (30/90) stx2 and 14.5% (13/90) both genes. In search of virulence factors, 47.7% and 32.2% of the isolates carried the genes saa and cnf1. According to the analysis of the antimicrobial resistance profile, 83.3% (75/90) were resistant to at least one of the antibiotics tested. In phylogenetic classification grouped 24.4% (22/90) in group D (pathogenic), 32.2% (29/90) in group B1 (commensal) and 43.3% (39/90) in group A (commensal). The presence of several virulence factors as well as the high number of multiresistant isolates found in this study support the statement that sheep are potential carriers of pathogens threatening public health.

Variability and inbreeding in semiexotic maize populations

Three semiexotic populations (CRE-01, CRE-02, CRE-03) obtained by incorporation of exotic germplasm (lines from CIMMYT, Colombia; selected for resistance to corn stunt complex) were evaluated in two cycles of recurrent selection with half-sib families. In cycle-I, samples comprising 50, 70, and 50 half-sib families were evaluated at Jataí (GO) and traits analyzed were ear yield, plant height, and ear height. For yield (t/ha), populations means were 5.86, 6.19, and 5.31, representing approximately 73% of hybrid check. Sets of parameters estimates representing the three populations were: [237, 485, and 608] for the additive genetic variance (σ(2)A: g/plant); [0.393, 0.584, 0.658] for the coefficient of heritability (h(2)m: progeny mean basis), and [0.464, 0.684, and 0.801] for the index of variation (θ). In cycle-II, materials analyzed included 60 non-inbred (half-sib) and 60 inbred (S1) families from each population, evaluated at Anhembi (SP) with two replications; traits analyzed included ear yield plus ear weight and grains weight of four ears, two plant traits (plant height and ear height), two ear traits (length and diameter), two tassel traits (branch number and length), and resistance to corn stunt complex. Means of half-sib families for ear yield (t/ha) were [10.614, 10.419, 10.842], representing 83 to 86% of the hybrid check. The same pattern of variation was observed for ear weight and grain weight of four ears. Means of S1 families were [6.465, 5.527, 5.925] and the inbreeding depression in percent of the non-inbred families were [39.1, 46.9, 45.3]. Estimates for other traits are also shown.

Lecitina, silicone e amido na adubação foliar de couve (Brassica oleracea L.)

Objetivou-se, no presente trabalho, avaliar os efeitos que a lecitina, amido e silicone possam ter na eficiencia da adubacao foliar, utilizando-se sais e quelatos como fonte de micronutrientes. Para isso foi realizado um experimento em que avaliaram-se os efeitos da adicao de diferentes adjuvantes em relacao a absorcao e translocacao de zinco e manganes na forma de sais e quelatos. O delineamento utilizado foi o inteiramente casualizado, com seis repeticoes, com quatro fatores em estudo e dois niveis cada, perfazendo um fatorial 2x2x2x2, totalizando dezesseis tratamentos. Alem dos tratamentos, foi adicionada testemunha como tratamento adicional, perfazendo, assim, um total de 102 parcelas. Cada parcela foi constituida por um vaso, contendo uma planta de couve-manteiga (Brassica oleracea L. var. acephala DC.). Os tratamentos constaram de combinacoes entre 2 fontes (sulfato e quelato) e de presenca ou ausencia de tres substâncias na calda de pulverizacao: lecitina de soja desengordurada, um siliconado comercial e gel de amido de mandioca. A determinacao dos efeitos constituiu-se na analise do teor de zinco e manganes nas folhas novas 30 dias apos a pulverizacao. A adicao de lecitina aumentou a absorcao do sulfato de zinco ao passo que o produto siliconado aumentou a absorcao do zinco quelatizado. Tanto a lecitina quanto o produto siliconado, quando adicionados a calda de pulverizacao, aumentaram o teor de manganes. O gel de amido nao aumentou a absorcao de nenhum micronutriente.