Leandro Paiola Albrecht

Qualidade de sementes de quatro cultivares de soja, colhidas em dois locais no estado do Mato Grosso do Sul

O trabalho foi realizado com objetivo de avaliar a qualidade das sementes de quatro cultivares de soja (BRS 133, BRS 206, BRS 239 e CD 202), colhidas em quatro epocas (Estadio R7 e 7, 14 e 21 dias apos a primeira epoca) e produzidas em dois locais do Estado do Mato Grosso do Sul (Sidrolândia e Dourados), nos anos agricolas de 2004/05 e 2005/06. O delineamento experimental utilizado foi em blocos casualizados com tres repeticoes e tratamentos arranjados no esquema de parcelas subdivididas. As parcelas foram constituidas pelas cultivares de soja e as subparcelas pelas epocas de colheita. A germinacao foi avaliada pelo teste de germinacao; teste de envelhecimento acelerado e o vigor pelo teste de frio sem solo, teste de emergencia das plântulas em substrato de areia e teste de sanidade. Os dados coletados nos diferentes locais foram submetidos a analise de variância conjunta de parcelas subdivididas e, na presenca de interacao significativa, foram realizados os desdobramentos necessarios para os dois anos agricolas, separadamente. No ano agricola 2004/05, as cultivares BRS 239 e CD 202 apresentaram-se com elevada porcentagem de germinacao para a producao de sementes na regiao de Dourados. No ano agricola 2005/06, a cultivar BRS 239 foi a que apresentou melhor germinacao e vigor. A cultivar BRS 239 apresenta menor indice de infeccao de microrganismos em relacao a cultivar BRS 206. Melhor qualidade de sementes e obtida das sementes colhidas aos sete dias apos o estadio R7. Em relacao a qualidade sanitaria das sementes, a medida que se retarda a epoca de colheita, a porcentagem total de microrganismos aumenta linearmente para todas as cultivares.

Testes de laboratório em sementes de canola e a correlação com a emergência das plântulas em campo

The establishment of patterns for the evaluation of canola physiological seed quality is extremely useful for obtaining a good stand in the field. Thus, with the objective of comparing the efficiency of different tests for the evaluation of canola physiological seed quality and to verify their relationships with seedling emergence in the field, four seed lots of canola were evaluated by the standard germination test, first count germination, electrical conductivity, accelerated aging, modified cold test, seedling emergence on sand seedbed, speed of emergence seedbed and speed of emergence-index in sand, seedling emergence in field, weight of a thousand seeds and the health test. Among the tests carried out in the laboratory, the germination test and first counting of the germination, electrical conductivity and accelerated aging are considered the most efficient to differentiate field emergence performance of canola seed lots. The speed of emergence-index and the speed of emergence in sand seedbed are not suitable to evaluate canola seed quality.

Componentes do rendimento, teores de isoflavonas, proteínas, óleo e qualidade de sementes de soja

Soybean seeds have been used not only for animal, but also for human nutrition because of the presence of proteins; lipids; some vitamins and polyphenolic compounds, such as isoflavones, in their chemical composition. The antioxidant activity of isoflavones may be considered a safe mechanism of seed quality. This is due to the deterioration theory which leads to a cellular detriment because of the action of free radicals on cell membranes. Experiments were carried out during the 2004/05 agricultural year in two different sowing locations (Maringa and Umuarama). The objective of this study was to evaluate the yield, physiological quality of seeds produced in two sowing locations; to determine oil, protein and isoflavone contents; as well as to correlate isoflavone contents to the yield, physiological quality and oil-protein contents of soybean seeds. The seed quality was evaluated by the germination test (first count and final count); the tetrazolium test (vigor and viability) and the concentration of oil, protein and isoflavone tests. Analysis of the isoflavone contents showed that the BRS 133 and EMBRAPA 48 cultivars presented the highest isoflavone contents whereas the BR 36 cultivar showed the lowest isoflavone contents in both places. Germination was above 80% in all cultivars tested in Maringa. The correlation between isoflavones and the weight of one thousand seeds was negative for both locations.

Teores de óleo, proteínas e produtividade de soja em função da antecipação da semeadura na região oeste do Paraná

Early soybean sowing, especially using early cultivars is a practice that is adopted by many growers from the State of Parana in order to anticipate harvest and to enhance growing corn crop during the fall. Experiments of soybean cultivars competition trials were carried out at COODETEC in the city of Palotina, Parana State, aiming to evaluate the influence of early sowing on the chemical composition of seeds, as well as yield. A randomized block design, comprised by two crop years (2003/2004 and 2004/2005), three early cultivars (CD 202, CD 215 and CD 216); and five sowing times (09/15, 09/30, 10/15, 10/30 and 11/15) was utilized. Also, oil and protein content were also determined. The productivity (kg ha-1) was calculated using the yield of grain in each parcel. All data were submitted to variance analysis of group experiments along with all interactions and necessary adjustments. Results allowed to conclude that early sowing can influence grain yield and seed chemical composition.

Seed quality of soybean produced with bioregulator management

The objective of this study was to evaluate the physiological and sanitary quality of soybean seeds treated with the growth regulator Stimulate®. Seeds of the cultivar BRS 246 RR were planted in October of crop years 2007/2008 and 2008/2009, in a randomized complete block design with four replications. The treatments were set out in a factorial, with a combination of seed treatment and the growth regulator (with and without 0.500 L.100 kg-1 bean) at five product dosages (0, 0.125, 0.250, 0.375 and 0.500 L ha-1) with foliar application at two developmental crop stages (V5 or R3). The application of Stimulate® positively altered seed quality, especially at the V5 stage.

RR soybean seed quality after application of glyphosate in different stages of crop development

In consequence of several studies and speculations concerning the issue of RR transgenic soybean after the application of glyphosate, additional scientific investigations became necessary to clarify the actual viability of the product use when applied in different developmental stages of the soybean crop. Therefore, this study was aimed to evaluate the physiological quality as well as seed health quality of RR soybean subjected to application of the herbicide glyphosate in different phonological stages of the transgenic soybean, cultivar CD 219RR. For this, an experiment with a complete block experimental design with treatments randomly distributed within the block, with four replications, was carried out. The assessed treatments were foliar sprayings of glyphosate in three increasing dosages [0 (control); 1,440 g ha-1; and 2,880 g ha-1] of acid equivalent, applied in two crop developmental stages: vegetative (V6) and reproductive (R2). The variables assessed were: germination; first count of germination; fresh and dry mass of seedlings, lengths of seedling and root; vigor and viability by the tetrazolium test; and seed health quality. Glyphosate application may adversely affect physiological quality of RR soybean seeds, when applied in dosages varying from 1,440 to 2,880 g acid equivalent per hectare at the stages V6 and R2.