Antonio Carlos Souza Albuquerque Barros

A secagem de sementes

The drying operation of the seeds is fundamental in the production system because it reduces the tenor of water to allow its physiologic quality preservation during the storage and makes possible the anticipation of the crop avoiding losses of several CAUSE. In the choice of the drying method, the amount seeds factor is limited and, when we need to dry larger amounts the use of artificial drying is indispensable, whose operation costs are related, mainly, with volume, drying speed and temperature of the air. It becomes important that the operators are aware of the drying conditions that they get to provide to the seeds, aiming to maximize the possible benefits or, on the other hand, to minimize to the maximum the inevitable and irreversible losses that happen from the moment that the seeds reach its maximum quality, still in the field.

Qualidade fisiológica e produtividade de sementes de soja

There is currently intense research on obtaining information about higher soybean productivity and, in this context, using high quality seeds is extremely important to farmers. With the objective of evaluating the effects of soybean seed vigor on productivity, seed lots with high and low vigor were sown at three different densities: the certified germination %, the certified germination % plus 15% as a correction factor and, from the result of field emergence. The seedling population after emergence was not changed so that the field condition that farmers face when sowing variable quality seeds could be reproduced. During plant development, the following parameters were evaluated: initial stand, plant height at 21 and 75 days after sowing, number of pods and seeds per plant, weight of one thousand seeds, and yield/area. The results showed that: the yield/area of high vigor seed lots is on average up to 9% higher; the seedlings from high vigor seeds are taller at 21 days after sowing.

Efeito da qualidade fisiológica das sementes e da densidade de semeadura sobre o rendimento de grãos e qualidade industrial em arroz

An experiment was conducted in the Centro Agropecuario da Palma, at the Universidade Federal de Pelotas (CAP/UFPel) with the objective of evaluating the effect of rice seed physiological quality and seeding rate upon grain yield and grain integrity percentage. It was tested in a factorial combination in two crop years (2000/2001 and 2001/2002), two physiological quality levels and different seeding rates. Seed lots of the cultivar IRGA 417 were obtained from official seed growers of Rio Grande do Sul State, Brazil. Seeding rates were 80, 140 and 200 kg per hectare in 2000/2001 and 80 and 150 kg in 2001/2002. The use of high physiological quality level seed lots propitiated yield increases of 8,2% and 9,0% in 2000/2001 and 2001/2002, corresponding to 622 kg ha-1 and 660 kg ha-1, respectivelly. Otherwise, different seeding rates did not affect grain yield.The use of lots of low seed physiological quality caused uneven maturation, reduction in 1000 grain weight. On the other hand, grain integrity percentage and index of harvesting were not affected. The variation in the seeding rate did not affect maturation uniformity, grain integrity yield and weight of 1000 grains.

Physiological performance of soybean seeds from conventional and transgenic cultivars treated with glyphosate

The objective of this study was to evaluate the physiological quality of seeds from conventional (cultivar CD 216) and transgenic (cultivar CD 212RR) soybeans treated with glyphosate. Seeds were soaked in dosages of zero; 1.8; 3.6; 5.4 and 7.2 g.L-1 of acid equivalent of glyphosate for 30 minutes. Seed quality was evaluated from the tests of first count germination, germination, electrical conductivity, emergence speed index, seedling emergence, root and shoot length and total dry matter. It was concluded that the physiological quality of the CD 212RR seeds seeds is affected by glyphosate and as dosages increased, soybean seed quality decreased. Based on this conclusion, it is important that care be taken to avoid problems with seed germination and soybean field establishment when glyphosate is used in burndown or for the control of cover crops. A certain period of time between the control of weeds or of cover plants should be respected to reduce the glyphosate transfer from target to non-target plants, thus avoiding problems with germination and soybean crop establishment.

Qualidade fisiológica de sementes de urucum armazenadas em diferentes ambientes e embalagens

Urucum (Bixa orellana L.) is a species of great commercial interest, from whose main product, the seed, is extracted the bixina and norbixina coloring, of great interest in national and international markets. The objective of this study was to evaluate urucum seed physiological quality of the cultivar Bico de Pato, stored for period of 12 months in four environments (environmental condition, cold chamber, refrigerator and freezer) and packed in bags (trifoliated envelopes of aluminum-polyethylene-paper, plastic packing in vacuum, black polyethylene). After moisture determination, the seeds were scarified mechanically. They were evaluated at 90, 180, 270, 360th days of storage and submitted to the germination, first counting of germination and germination speed index tests. It was possible to conclude that urucum seeds with 7,0% moisture, packed in vacuum maintained physiological quality for 270 days and that the storage in freezer and refrigerator, in aluminum and plastic bags in vacuum, provided better physiological seed quality.

Tipologias e composto mercadológico de empresas de sementes de trigo e soja do Rio Grande do Sul

Two experiments were carried out to study the correction effect of the electrical conductivity value of the imbibition solution (mS cm-1 g-1) as affected by the conductivity of the water used in the test and the effects seed number and volume of water on the electric conductivity of the imbibition solution, to improve the methodology for this test in the evaluation of pearl millet seed vigor. Three seed lots were used, lot 1 represented by cv. Comum and the lots 2 and 3 by cv. BN2. In experiment 1 the electrical conductivities of 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100 seeds of lot 1 were evaluated and placed in 100 ml distilled water. In experiment 2 the combinations of 25, 50 and 100 seeds and 50, 75 and 100 ml of water were studied for the three lots. The conductivity tests were carried out at 25 Co, with 24h imbibition. The statistical model was the complete randomized block, with four replications for all the treatments. The conductivity of the water used in the test influenced the calculated value of the electrical conductivity of the imbibition solution for pearl millet seeds, when the value of the conductivity of the solution is low. The best combination for the electrical conductivity test for pearl millet seeds was 100 seeds and 100 ml of water, because it identified best the differences among the lots.The seed marketing uses the same concepts applied to others activities of agribusiness, in which the marketing mix (product, price, place and promotion) is used. However, there are few studies that consider the seed company peculiarities. To fullfill this gap, the present study was accomplished with the objective of identifying the seed companies profile and its marketing mix, centering the analysis on how the seed companies act. This study, starting with primary data, tried to explain the internal operation of the seed companies, starting whit its profile and with components of the marketig mix. Multivariate techniques of analysis were used. To identify typologies, analysis of main components was accomplished with the internal variables of the companies. The study enlarged a traditional dichotomy in Rio Grande do Sul State, among private and cooperative seed companies, allowing to build four new different typologies. Although the typologies were built, they rarely showed differentiation in the correspondence factorial analysis that investigated its management and the marketing mix, indicating that general characteristics of the sector are more important than the particular typologies.

Reflexos do mecanismo de ação de herbicidas na qualidade fisiológica de sementes e na atividade enzimática em plântulas de arroz

The present work had the objective of evaluating the residual effect of the herbicides in the physiologic quality and in the enzymatic activity in rice seeds. Four herbicides were tested (clomazone, quinclorac, propanil, byspiribac-sodium) in two application times and four rice cultivars (ARRANK, BRS-PELOTA, BR-IRGA 410 and BR-IRGA 417). To evaluate the physiologic quality of the seeds the germination test, cold test and electric conductivity were accomplished. For the enzymatic activity it was evaluated the following enzymes: esterase, glutamate oxaloacetate transaminase, malate dehydrogenase, glutamate dehydrogenase, phosphoglucose isomerase and the acid phosphatase. The herbicides of different mechanisms of action in post emergence application, can modify rice physiologic performance. The enzymatic expression varies as a function of the genotype and it is not dependent of the herbicide residual effect.

Envelhecimento acelerado em sementes de azevém com e sem solução salina e saturada

The objective of the present study was to evaluate the methodology of the accelerated aging test to evaluate the physiological potential of s ryegrass seeds, as well as verify the possibility of the use of unsaturated and saturated solution of NaCl as an option for control of water uptake by seeds during the test without reducing its sensitivity. Four lots of ryegrass seeds were tested for germination, seedling emergence, speed emergence and accelerated aging (periods of 24, 48, 72 and 96h, with or without the use of saturated and saline solution of NaCl). The use of unsaturated and saturated solution of NaCl reduces water absorption by ryegrass seeds during the accelerated aging test, resulting in a rate of deterioration is less pronounced ,less drastic and more uniform results. Option 24h with unsaturated solution (SNS) was only able to stratify plots into two groups and should not be designated as promising. Thus, it should be used the 48h saturated NaCl solution (SSS), which stratified into three lots.

Performance of lowland rice seeds coated with dolomitic limestone and aluminum silicate

The objective of this study was to evaluate the performance of seeds of two cultivars of lowland rice (Oryza sativa L.), coated with dolomitic limestone and aluminum silicate. It was used a completely randomized experimental design, with the treatments arranged in a 4 X 2 factorial scheme [4 treatments: dolomitic limestone; dolomitic limestone + aluminum silicate; aluminum silicate, at the dosages of 50 g/100 kg of seeds; and control (without the products) X 2 cultivars: IRGA424 and IRGA 422 CL], totaling eight treatments with four replications each. The variables analyzed were: fresh and dry weights of aerial biomass; plant height; leaf area at 10, 20, and 30 days after emergence (DAE). The physiological quality of seeds was also assessed using tests of: seed emergence; first count of germination; emergence speed index; and field emergence. It was concluded that the coating of rice seeds with dolomitic limestone and aluminum silicate does not affect seed germination and field seedling emergence. Aluminum silicate used via seed coating on cultivar IRGA 424 promoted greater leaf area, after 20 DAE. The dolomitic limestone and the aluminum silicate used via seed coating generated plants with larger dry biomass, after 20 DAE, for the cultivar IRGA 422 CL.

Cálcio e silício na produção e qualidade de sementes de soja

A utilizacao de produtos naturais na protecao de plantas constitui-se em uma ferramenta importante para o agricultor de producao orgânica. O trabalho foi realizado com objetivo de avaliar a eficiencia da aplicacao de calcio e silicio na producao e qualidade das sementes de soja. Foram utilizadas sementes de soja orgânica (Glycine max L.) cultivar BR36, proveniente dessa cooperativa, na safra 2004/2005. O modelo experimental utilizado foi de blocos inteiramente casualizado, com cinco tratamentos (calcio 40, calcio 50, silicio 40, silicio 50 e testemunha). Os tratamentos foram comparados pelo teste de Duncan, 5% de probabilidade. As variaveis dos componentes de producao foram: numero de vagens por planta, numero de sementes por vagem, produtividade e rendimento de graos. A qualidade fisiologica das sementes foi determinada pelos testes: germinacao, primeira contagem de germinacao, frio, condutividade eletrica e envelhecimento acelerado. Conclui-se que plantas de soja tratadas com calcio e silicio produzem sementes de maior qualidade fisiologica; os tratamentos com aplicacao de Ca e Si reduzem o rendimento de sementes por unidade de area.