Silmar Teichert Peske

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.

Vigor de sementes e competição intra-específica em soja

The objective of this research was to evaluate the effect of high and low vigor soybean seeds combinations distribution in the planting row on individual plants and different communities performance. The cultivar BRS 154 was used. Six seed vigor combinations were used. Plants from high vigor seeds had higher leaf area, dry matter accumulation and seed yield than plants from low vigor seeds. Plants from high vigor seeds do not have dominance effect on plants from low vigor adjacent in the row. The increases in proportion of high vigor seeds in the establishment of the plants communities provided linears increments in leaf area index, dry matter production and seeds yield. The population established with all plants from of high vigor seeds out yield in more than 30% the population established only with plants from low vigor seeds.The objective of this research was to evaluate the effect of high and low vigor soybean seeds combinations distribution in the planting row on individual plants and different communities performance. The cultivar BRS 154 was used. Six seed vigor combinations were used. Plants from high vigor seeds had higher leaf area, dry matter accumulation and seed yield than plants from low vigor seeds. Plants from high vigor seeds do not have dominance effect on plants from low vigor adjacent in the row. The increases in proportion of high vigor seeds in the establishment of the plants communities provided linears increments in leaf area index, dry matter production and seeds yield. The population established with all plants from of high vigor seeds out yield in more than 30% the population established only with plants from low vigor seeds.

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.

Armazenamento em sistema a frio de sementes de soja tratadas com fungicida

The objective of this study was to evaluate physiological quality and health of soybean seeds, treated or not with fungicide Dipheconazol in the dosage of 0,05g i.a./kg- of seeds, in an open storage with cooling system. The seeds stored in the upper portion of two piles of 1.200 bags each, in the 23rd ballast (penultimate), in several positions in relation to the central duct of aeration of the cooling system, were evaluated for standard germination, vigor (accelerated ageing, field emergence and tetrazolium) and health (blotter test) during a period of eight months. Soybean seeds with initial moisture content of 14%, store in the upper part of the piles with cooling aeration system, reduced its physiological quality after two months of storage. The seeds treated with fungicide showed better performance in the initial periods of storage, but not after four months. The seed moisture content variation over the storage period was significant, starting with 14% ending with 10%. After 30 days, even so, the seeds still showed 13,8% moisture content, being probable the cause of reduction of the physiological quality. The reduction of 0,6 percentage points per month of storage was not sufficient to delay deterioration effects on seeds.

Performance of zinc coated irrigated rice seeds

A cultura do arroz constitui um dos principais cereais que apresenta alta resposta a aplicacao de zinco, sendo a cultura mais sensivel a deficiencia deste elemento. O objetivo nesta pesquisa foi avaliar os efeitos do recobrimento de diferentes doses de zinco em sementes de arroz irrigado, sobre o desempenho das sementes e os componentes do rendimento. O trabalho foi conduzido na Universidade Federal de Pelotas no ano agricola de 2006/07. Os tratamentos consistiram na aplicacao de uma mistura de sulfato de zinco heptahidratado (22% Zn), com seis doses: zero; 0,37; 0,47; 0,57; 0,67 e 0,77 g kg-1 de semente. Alem do recobrimento com sulfato de zinco, utilizou-se para todos os tratamentos uma mistura de fungicida (3 mL kg-1), polimero CF Clear® (200 mg kg-1) e corante (4 mL kg-1). O delineamento experimental utilizado foi o completamente casualizado com quatro repeticoes. A qualidade das sementes foi avaliada por meio do teste de germinacao e testes de vigor (comprimento da parte aerea e raiz, biomassa seca da parte aerea e raiz de plântulas). Em casa de vegetacao foram avaliados, ainda, os componentes do rendimento (numero de paniculas por planta, numero de graos por panicula e peso de graos por planta). Com base nos resultados obtiveram-se as seguintes conclusoes: 1 - O recobrimento de sementes de arroz com o zinco, dosagem de 0,77 g kg-1 de semente, aumenta o numero de graos por panicula e peso de graos por planta em condicoes de casa de vegetacao. 2 - Sementes de arroz recobertas com zinco geram plântulas com maior crescimento. 3 - O recobrimento das sementes com zinco nao afeta a germinacao.

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.

Onion (Allium cepa L.) pollen storage

Experimentos foram conduzidos no Laboratorio de Melhoramento Genetico da Embrapa Clima Temperado, em Pelotas, RS, com o objetivo de avaliar, in vitro, o potencial de armazenamento dos graos de polen de cebola da cv. Petrolini, em diferentes condicoes por dois anos. Para tanto, avaliou-se a percentagem de germinacao do grao de polen apos um e dois anos de armazenamento em criotubos, acondicionados em nitrogenio liquido (-196oC), e em frascos de vidro acondicionados no interior de dessecador contendo acido sulfurico e mantidos em freezer (-18oC). O polen conservado por um ano em nitrogenio liquido foi entao transferido para um refrigerador, registrando-se a percentagem de germinacao apos 10, 15, 20 e 30 dias de permanencia neste. O armazenamento em nitrogenio liquido foi o melhor ambiente para a conservacao dos graos de polen durante dois anos. As amostras armazenadas, por um ano, em nitrogenio liquido, que foram transferidas para refrigerador, conservaram-se viaveis por ate dez dias.

Enchimento de sementes em linhas quase-isogênicas de trigo com presença e ausência do caráter "stay-green"

The stay-green trait has been used as an alternative to reduce the senescence in wheat, resulting in an effective functional increase of the leaf area, and an increase in the rate and duration of the seed filling period. The objective of this work was to analyse the rate of dry matter accumulation and the duration of the seed filling period of near-isogenic lines of wheat differentiated by the presence and absence of the stay-green trait. The experiment was conducted in the Experimental Center of Palma, in Pelotas, State of Rio Grande do Sul, in Brazil. Four near-isogenic lines were used: F6-SG and F6-SZ in the year of 2000 and F7-SG and F7-SZ in the year 2001, with five replications. The stay-green trait allowed a higher deposition of plant reserves in the seed, during the phase close to the point of physiological maturity. The duration of the seed filling period in the evaluated genotypes was associated to the dry matter accumulation in the seed. Promoting a larger weight is a trait responsible for the selection of genotypes with high rates of seed filling.

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.

Expressão diferencial de isoenzimas durante o processo de germinação de sementes de arroz em grandes profundidades de semeadura

The germination process consists of a complex and regulated group of physiologic and biochemical events that happen in the seed soon after beginning water absorption. The restart of the embryo growth due to water absorption involves the reactivation of many enzymes that will hydrolyze reserve substances, to supply redox potential and energy for germination. Plantlet emergence in monocotyledonous depends, principally, on the sowing depth and other factors such as genetic potential and seed vigor, because the embryo is nurtured by the seed stores along. In this study, isoenzimatic patterns of Esterase (EST), Acid Phosphatase (ACP), Malate Dehydrogenase (MDH), Alcohol Dehydrogenase (ADH) and Glutamate Oxalacetate Transaminase (GOT) were analyzed among germination processes at 20 cm in 34 red rice ecotypes and 5 commercial cultivars with the objective of identifying differential expression variations in the isoenzimatic systems analyzed. The five isoenzimatic systems analyzed showed variations in the enzymatic expression, mainly when compared with the patterns of the dry seed with the developing plantlets. From the results obtained it was concluded that ere is differential expression in the isozyme genes Esterase (EST), Acid Phosphatase (ACP), Malate Dehydrogenase (MDH), Alcohol Dehydrogenase (ADH) and Glutamate Oxalacetate Transaminase (GOT), showing participation in the germination process in rice.