Manoel de Souza Maia

Vigor de sementes e análise de crescimento de aveia preta

This study was carried out in Capao do Leao, RS, Brazil, with the objective of evaluating the effect of seed vigor on the growth of two cultivars of cultivated black oats (Avena strigosa Schreb), as well as to verify possible interactions with plant population (150, 300 and 450 pl m-2). Seed vigor and plant population affected dry matter production during the vegetative period. The effects were reduced progressively in the growing season, with no more difference after anthesis. The extreme levels of seed vigor and plant population produced differences in dry matter yield of 410 kg ha-1 and 480 kg ha-1, respectively, at the 75th day after emergence, these effects were due to differences in crop growth rates. A compensatory effect of the plant population on dry matter production was verified, so that the effect of low seed vigor could be compensated by an increase in plant population; the lower the seed vigor level, the greater was the plant population required. High vigor seeds also compensated the effects of low plant populations.

Qualidade fisiológica e sanitária de sementes de Feijão-miúdo beneficiadas em mesa gravitacional

The objective of this work was to evaluate the effect of the gravitational table in the sanitary and physiological quality in seeds lots of (Vigna unguiculata (L.) Walp). After the cleanness, seeds of four genotypes (Peanut, Bay, Mosqueado and Preto) had been submitted to the action of the gravity table with discharge divided in three fractions: superior, intermediate and inferior. It is admitted himself as inferior extremity, the situated one in the lowest point of the discharge when considered the lateral inclination of the table and, as superior, the opposing one. Physiological quality of the seeds was evaluated by germination test and vigor (accelerated aging, electric conductivity and cold test). For evaluation of the sanitary quality the blotter test was used. It was observed that the separation of the seeds through the gravitational table provided positive alterations in the physiological and sanitary quality of the lots of beans-small seeds for all the evaluated genotypes, justifying her use in the improvement of seeds of beans-small.

Vigor de sementes de populações de aveia preta: II. Desempenho e utilização de nitrogênio

O efeito do vigor das sementes e das possiveis interacoes com a variacao na populacao de plantas (150, 300 e 450 pl/m2), sobre o desempenho a campo de dois cultivares de aveia preta (Avena strigosa Schreb), e sobre alguns componentes envolvidos na utilizacao do nitrogenio, foi avaliado neste trabalho. O rendimento biologico na antese e na maturacao, a remobilizacao de nitrogenio, a eficiencia de remobilizacao e de utilizacao de nitrogenio, a concentracao de nitrogenio nos tecidos na maturacao e a qualidade fisiologica das sementes produzidas, nao foram afetados pela diferenca nos niveis de vigor das sementes e pela variacao na populacao de plantas. O rendimento de graos e os componentes do rendimento nao foram afetados pelo nivel de vigor das sementes, embora as baixas populacoes de plantas tenham reduzido o rendimento de graos. As plantas provenientes de sementes de menor vigor foram mais eficientes na alocacao de produtos da fotossintese nas sementes. A cultivar Embrapa 29 foi menos eficientes na acumulacao de nitrogenio na biomassa da parte aerea na epoca da antese, e na biomassa da parte vegetativa aerea na epoca da maturacao, do que a cultivar Embrapa 140. Ocorreram diferencas genotipicas na resposta ao vigor das sementes para algumas caracteristicas ligadas a eficiencia no uso de nitrogenio. Nao foram observadas interacoes entre niveis de vigor de sementes e populacoes de plantas.

Level of natural fungus infection related to the quality of peanut seeds

RESUMEN- En semillas de mani, la relacion entre el nivel de infeccion fungica natural y la calidad, no ha sido establecida claramente. El objetivo de este trabajo fue evaluar la relacion entre el nivel de infeccion fungica natural y la calidad de semillas de mani, en terminos de viabilidad y vigor. Los ensayos se realizaron con 10 lotes de semillas de mani cv Florman seleccionados por su nivel de calidad sanitaria, provenientes del area nucleo manisera argentina. Entre los ensayos realizados, aquellos que se identificaron como sensibles y que permiten establecer los diferentes niveles de calidad fueron germinacion, vigor por tetrazolio y conductividad. El porcentaje de aceite solo detecto variaciones en los lotes de alto nivel de infeccion y no hubo modificaciones en la relacion oleico/linoleico en ninguno de los casos. De los resultados obtenidos se concluye que los niveles de calidad de los lotes evaluados, estan estrechamente correlacionados con la calidad fisiosanitaria. Terminos indices: Arachis hypogaea, hongos, viabilidad, vigor. LEVEL OF NATURAL FUNGUS INFECTION RELATED TO THE QUALITY OF PEANUT SEEDS

ESTABELECIMENTO DE CONDIÇÕES DE LUZ E TEMPERATURA PARA GERMINAÇÃO DE SEMENTES DE AMENDOIM FORRAGEIRO 1

The objective of this study was to compare different light and temperature regimes to establish conditions for the standard germination test of Brazilian peanut (Arachis pintoi Krapov. & W.C. Gregory). The germination tests were conducted with 200 seeds (4 x 50), using rolled paper towel. The experiment consisted of two stages. In the first, the temperatures used were 25 oC, 30 oC, 35 oC, 25-30 oC, 25-35 oC and 30-35 oC, with and without light. In the second, the alternating temperatures of 25-30 oC and 25-35 oC with light were compared with the recommended (20-30 °C with light) for peanut (Arachis hypogaea L.). Three statistical repetitions were used, in a completely randomized design. It was verified that the use of alternating temperatures promoted a significant decrease in the number of hard seeds because dormancy was overcome. Among the treatments with constant temperature, 30 oC with light showed the highest number of normal seedlings. The temperatures of 20-30 oC and 25-30 oC, with light, were the most recommended for the germination test. Daily countings of normal seedlings showed that the best day for the first counting was the 8th and for the last one the 14th day of the germination test.

Produção de sementes de cevadilha-vacariana (Bromus auletius Trinius) em função da cronologia de desenvolvimento dos perfilhos reprodutivos

Native pastures constitute the feed basis for livestock in Southern Brazil. These natural grazing fields are constituted mainly by summer species, paralyzing their growth and loosing quality in the autumn-winter period. This factor causes high economic losses to the livestock producers. Bromus auleticus is a temperate climate perennial grass, whose contribution to forage occurs at a time of crucial feeding needs of the herds. The objective of the present study was to evaluate the yield components and the quality of B. auleticus seeds according to the chronological order of reproductive tiller development. Thirty representative plants were selected and their tillers were labeled according to the chronological order of differentiation and elongation. Harvesting was done at the time of full maturation of each tiller, generally 30 days after maximum anthesis. The chronological order of tiller development determined the yield of Bromus auleticus seeds. Seed yield of B. auleticus was similar in the first, second and third tillers which developed in a plant, being responsible for about 75% of the yield. These reproductive tillers were taller and had more seeds per panicle, heavier and higher germinating seeds, and had less seed dormancy than the other tillers on the same plant.

Efecto de la temperatura y la luz en la germinación de semillas de Paspalum guenoarum

Paspalum guenoarum is a forage species recently adapted to the Argentine subtropical area, which would offer advantages to producers by covering the seasonal pasture deficiency of the region. Adequate methodologies of quality control should be taken into account for seed production and trading. The germination assay is an effective tool to establish the quality of seed lots, but to date, there are no precise specifications for the development of this methodology in P. guenoarum. Both temperature and light are determinant in the expression of the maximum germinative potential, but the most favourable magnitudes and regimens must be found for each species. For these reasons, the objective of this study was to establish the adequate temperature and light conditions to evaluate the quality by means of the germination assay in the laboratory. A completely randomised 2 x 2 factor design with four replications of 100 seeds was used. Factors were constant temperature at 27oC and alternating temperature at 20-35oC and continuous light and in cycles of 8 h light and 16 h darkness. The germination rate and the germination percentage were determined. The results indicated that the alternating temperature at 20-35oC was the most appropriate to express the germination potential, regardless of the light regime.

Testes para avaliação da qualidade fisiológica de sementes de milheto

The objective of this study was to evaluate the comparative efficiency of different tests in assessing the vigor of millet seed lots (Pennisetum americanum (L) Leeke). Six lots were evaluated by the following tests: germination test, cold test, electrical conductivity, emergence on sand, seedling dry mass, weight of thousand seeds and both emergency and height of seedlings in the field. The experiment was a completely randomized block design with four replications. The results showed that: a) the cold test separated millet seed lots into different physiological quality levels; and b) the seedling dry mass test did not show association with the vigor expression of millet seeds.Sunflower crop was based, as yet, on high linoleic cultivars, but in the last years request for oil with higher content of oleic acid has increased, due to their dietary characteristics. At the beginning, high oleic cultivars were used to be sown in warm regions, but then the concern about growing it in temperate areas, as the south-east of Buenos Aires Province, was posed. In this region, early sowings are recommended, so that grain filling matches with a period of appropriate hydric and light conditions, as to result in greater yields. However, early sowings are limited by low soil temperature, that delays seedling emergence, resulting in heterogeneous stand establishment. The aim of this work was to evaluate seed performance of four high oleic cultivars in the southern area of Buenos Aires Province, by means of vigor tests and field trials. Germination, cold, tetrazolium viability, tetrazolium viability with cold, accelerated ageing tests and three field sowings at different soil temperatures were performed. Data were analyzed by Anova using generalised linear models, and tests and cultivars were contrasted among themselves. Similar seedling emergence under optimal and suboptimal temperatures for high oleic and high linoleic cultivars was recorded. The success of seedling establishment does not appear to be related to the acidic composition of seeds.