Soil management and topdressing nitrogen doses on upland rice

The influences of soil management and nitrogen fertilization are not well defined for upland rice. Thus, this research was carried out to evaluate the yield components, milled grain yield, and grain yield of upland rice cultivars under sprinkler irrigation, according to soil management and topdressing nitrogen doses. The experiment was conducted in Selvíria, Mato Grosso do Sul State, Brazil, under field conditions, for two consecutive harvest times: 2003/2004 (BRS Talento cultivar) and 2004/2005 (IAC 202 cultivar). The randomized blocks design was adopted, consisting of the combination of three soil management systems (disc harrow + leveling disc harrow, scarifier + leveling disc harrow, and no-till) and six topdressing nitrogen doses (0 kg ha-1, 25 kg ha-1, 50 kg ha-1, 75 kg ha-1, 100 kg ha-1, and 125 kg ha-1), with four replications. The leaf N concentration, plant height, yield components, milled grain yield, and grain yield were evaluated. The scarifier + leveling disc harrow system provided the highest grain yield for both cultivars, while the topdressing nitrogen fertilization just affected the IAC 202 cultivar yield, without affecting the milled grains yield

Nitrogen fertilization and soil management of winter common bean crop

A adoção de manejo cultural adequado, dentro do qual se insere a prática da adubação e do preparo do solo, é importante no sentido de aumentar a eficiência da planta na utilização dos recursos disponíveis. Este trabalho foi desenvolvido durante três anos, objetivando avaliar, no feijoeiro irrigado (Phaseolus vulgaris) "de inverno", o efeito da aplicação de doses de nitrogênio em cobertura (0, 25, 50, 75 e 100 kg ha-1), sob diferentes sistemas de preparo de solo (convencional, mínimo e direto). O delineamento estatístico utilizado foi em blocos casualisados dispostos em faixas para os sistemas de preparo do solo, com casualização dentro destes para as doses de nitrogênio, com quatro repetições. Foram avaliados: florescimento pleno, matéria seca de plantas, número de vagens e de grãos por planta, número de grãos por vagem, massa de 100 grãos, ciclo, rendimento de grãos e teor de nitrogênio nas plantas. O rendimento de grãos foi influenciado pelas doses de nitrogênio e incrementos significativos foram obtidos com a aplicação de 75 a 100 kg N ha-1. Os sistemas de preparo do solo não influenciaram no rendimento de grãos, embora o "cultivo mínimo" tenha se sobressaído nos dois primeiros anos.The adoption of appropriate cultural management, which includes nitrogen fertilization and soil tillage system, is very important to increase the efficiency of plant in the utilization of available resource. This research work was conducted for three years aiming at evaluating the effect of sidedressing nitrogen application (0, 25, 50, 75, and 100 kg ha-1) on winter bean crop under different systems of soil management (conventional, minimal, and no-tillage systems). The experimental design was a randomized block arranged in strips relative to tillage systems, with random distribution of nitrogen doses into each strip, with four replications. Grain yield was affected by nitrogen rates and significant increases were obtained with the application of 75 to 100 kg N ha-1. Soil management did not affect grain yield, although the "minimum system" provided better results in the two first years

Cover crops and nitrogen doses in wheat under no-tillage system

The application of conservation practices in production systems is essential to the sustainability of the agricultural production capacity. The use of different cover crops can reduce the need of topdressing nitrogen fertilizers in wheat crops. This study aimed at evaluating the influence of cover crops residues (millet, sunn hemp, pigeon pea, millet + sunn hemp, millet + pigeon pea and fallow ground), grown previously to the summer crop (rice), and topdressing nitrogen doses (0 kg ha-1, 25 kg ha-1, 50 kg ha-1, 75 kg ha-1, 100 kg ha-1 and 125 kg ha-1), in the development and yield of wheat under no-tillage system. The experiment was carried out in Selvíria, Mato Grosso do Sul State, Brazil, in a Red Oxisol, in 2009/2010 and 2010/2011. The experimental design was randomized blocks, in a 6x6 factorial scheme. The cover crops developed during August/October (2009/2010) and September/November (2010/2011), previously to the summer crop, with the chemical desiccation performed respectively at 73 and 55 days after sowing. The wheat (winter) was sown in May, in both periods, and harvested at 113 (2009/2010) and 106 (2010/2011) days after emergence. The cover crops residues of pigeon pea, sunn hemp and millet + sunn hemp, preceding wheat, provided higher wheat yields, relatively to the fallow ground. The wheat yield showed a quadratic response to the increase in the nitrogen availability, reaching higher yields with the nitrogen doses estimated in 113 kg ha-1 (2010) and 98 kg ha-1 (2011)

Conservação de folículos pré-antrais caprinos em solução salina ou à base de água de coco

The present study investigated the efficiency of saline solution and coconut water solution in the preservation of goat preantral follicles enclosed in ovarian tissue, at different temperatures and for different incubation periods. At the slaughterhouse, the ovarian pair was divided into 19 fragments; one ovarian fragment was immediately fixed for histology (control-time zero). The other 18 ovarian fragments were preserved in both solutions at 4ºC, 20ºC or 39ºC for 4 h, 12 h or 24 h. The histological analysis showed that the storage of ovarian fragments in both solutions at 4ºC for up to 24 h kept the percentage of normal preantral follicles similar to the control values. In contrast, preservation at 20°C or 39ºC, in either solution, reduced significantly the percentage of normal preantral follicles compared to the control values, except in saline solution at 20ºC for 4 h or in coconut water solution at 20ºC for 4 h and 12 h. In conclusion, this study shows that both solutions can be used with the same efficiency to preserve goat preantral follicles at 4°C, irrespective of the incubation time. However, to preserve goat preantral follicles at higher temperatures, coconut water solution is recommended.O presente estudo investigou a eficiência da solução salina e solução à base de água de coco na preservação de folículos pré-antrais inclusos em tecido ovariano, em diferentes temperaturas e diferentes tempos de incubação. No abatedouro, o par ovariano foi dividido em 19 fragmentos; um fragmento ovariano foi imediatamente fixado para histologia clássica (controle-tempo zero). Os outros 18 fragmentos ovarianos foram conservados em ambas as soluções a 4ºC, 20ºC ou 39ºC por 4 h, 12 h ou 24 h. A análise histológica mostrou que a conservação de fragmentos ovarianos em ambas as soluções a 4ºC por até 24 h mantém a percentagem de folículos pré-antrais normais similar aos valores do controle. Ao contrário, a conservação a 20°C ou 39ºC, em ambas as soluções, reduziu significativamente a percentagem de folículos pré-antrais normais comparado aos valores do controle, exceto em solução salina a 20ºC por 4 h ou em solução à base de água de coco a 20ºC por 4 h e 12 h. Em conclusão, esse estudo mostrou que ambas as soluções podem ser usadas com igual eficiência para conservar folículos pré-antrais caprinos a 4°C, independente do tempo de incubação. No entanto, para conservar folículos pré-antrais caprinos a altas temperaturas, a solução à base de água de coco é recomendada

Respuesta del maíz a la variación de la densidad de siembra y reducción del espaciamiento de hileras en el Cerrado

The management of spatial arrangement in the maize crop by alteration in the spacing between rows and sowing density has been appointed as one of the most important agronomic practices to maximize the grains yield. The objective of this study was to evaluate the behavior of maize in relation to the reduction of row spacing and the different sowing densities during the off season in the Cerrado region. The experimental design was randomized blocks in factorial scheme 2 x 5 with four replications. The treatments consisted of two spacing between rows (0.45 m and 0.90 m) and five sowing densities (40,000, 55,000, 70,000, 85,000 and 100,000 plants ha-1). It was not found significant response for the reduction of row spacing for the assessed characteristics in maize crop. The increase of sowing density resulted in plant height, number of grains per row and number of grains per ears reduction in the maize crop; however, there was an increase in yield until the density of 100,000 plants ha-1.El manejo de la disposición espacial en el maíz por cambio en el espaciamiento de hileras y en la densidad de siembra en las hileras ha sido considerado como una de las prácticas agronómicas más importantes para maximizar el rendimiento. El objetivo de este estudio fue evaluar el comportamiento de maíz por la reducción del espaciamiento de hileras y diferentes densidades de siembra durante el cultivo tardío (segunda temporada) en la región del bioma de Cerrado. El diseño experimental fue de bloques completos al azar en arreglo factorial 2 x 5 con cuatro repeticiones. Los tratamientos consistieron en dos distancias entre hileras (0,45 m 0,90 m) y cinco densidades de siembra (40.000, 55.000, 70.000, 85.000 y 100.000 plantas ha-1). No se ha verificado una respuesta significativa a la reducción de la distancia entre hileras en los caracteres evaluados en el maíz. El aumento de la densidad de siembra ocasionó al maíz reducción en altura de planta, número de granos por hilera y número de granos por mazorca, sin embargo, hube un aumento de la productividad hasta la densidad de 100.000 plantas ha-1.O manejo do arranjo espacial na cultura do milho pela alteração no espaçamento entre linhas e na densidade de semeadura na linha tem sido apontado como uma das práticas agronômicas mais importantes para maximizar a produtividade de grãos. O objetivo deste trabalho foi avaliar o comportamento do milho à redução de espaçamentos entre linhas e a diferentes densidades de semeadura no período da safrinha (2ª safra) na região do Cerrado. O delineamento experimental foi em blocos casualizados no esquema fatorial 2 x 5 com quatro repetições. Os tratamentos foram compostos por dois espaçamentos entre linhas (0,45 m e 0,90 m) e cinco densidades de semeadura (40.000, 55.000, 70.000, 85.000 e 100.000 plantas ha-1). Não verificou-se resposta significativa para a redução do espaçamento entre linhas para as características avaliadas na cultura do milho. O aumento da densidade de semeadura acarretou à cultura do milho redução na altura de planta, no número de grãos por fileira e no número de grãos por espiga, entretanto, houve incremento na produtividade até a densidade de 100.000 plantas ha-1

PREPARO DO SOLO, INOCULAÇÃO DE SEMENTES E DOSES DE NITROGÊNIO EM COBERTURA NO FEIJOEIRO COMUM DE INVERNO IRRIGADO

O feijão comum é uma planta exigente em nutrientes, principalmente em relação ao N. A adoção de um sistema de preparo que possibilite melhorar as condições do solo, associada ao fornecimento adequado de N pode ser de suma importância no sentido de aumentar a eficiência da planta na utilização dos recursos disponíveis. Assim propôs-se o estudo com o objetivo de avaliar o efeito de diferentes preparos do solo, inoculação de sementes com Rhizobium tropici e doses de N em cobertura no desenvolvimento e produtividade de grãos do feijão comum, cultivar Pérola, no período de inverno e irrigado. O experimento foi desenvolvido no município de Selvíria (MS) nos anos de 2006 e 2007. O delineamento estatístico foi blocos casualizados disposto em esquema fatorial 3 x 2 x 4, envolvendo três modalidades de preparo do solo (escarificador + grade niveladora, grade pesada + grade niveladora e plantio direto), inoculação ou não de sementes com estirpes de Rhizobium tropici (presença e ausência) e aplicação de N em cobertura aplicadas por ocasião da fase V4-5 (0, 60, 120 e 180 kg ha-1 ), com quatro repetições. Concluiu-se que o preparo do solo, com grade pesada, escarificador ou plantio direto e o uso de inoculação de sementes com Rhizobium tropici não alteram a produtividade de grãos da cultura e, a adubação nitrogenada em cobertura proporciona incremento na produtividade de grãos superior a 17% na dose de 180 kg de N ha-1 em relação ao tratamento testemunha. ABSTRACT Common bean is a demanding plant in nutrients, mainly in relation to nitrogen. The adoption of a management system that improves the soil conditions, associated to the appropriate nitrogen supply can be very important to increase the plant efficiency in the use of the available resources. This study aimed to evaluate different combinations of soil management, seed inoculation and nitrogen doses in the growth and yield of irrigated common bean plant in winter period. The experiment was conducted in Selvíria county (MS) in years of 2006 and 2007. A randomized completely blocks design in a factorial scheme 3 x 2 x 4, constituted by three soil management (chisel ploughing + leveling disk, heavy disk + leveling disk, and no till), seed inoculation with Rhizobium tropici ( with or without inoculation) and nitrogen doses at sidedressing on stage V4-5 (zero, 60, 120 and 180 kg ha-1), with four repetitions, was used. The soil management with chisel ploughing, heavy disk, or no till, and the use of seed inoculation with Rhizobium tropici does not interfere in the irrigated common bean yield; the nitrogen fertilization at sidedressing provides increment above 17% at dose of 180 kg ha-1 of nitrogen in relation to control

Degeneration rate of preantral follicles in the ovaries of goats

The degeneration rate of ovarian preantral follicles in goats, and the distribution in the follicular classes (primordial, primary or secondary) was assessed. Ovaries from adult goats were collected at a local slaughterhouse. To evaluate the morphology of the caprine preantral follicles in situ, one fragment from each ovary was fixed individually in Carnoy for 12 h, sectioned serially at a thickness of 7 μm and stained with Periodic Acid Shiff-hematoxylin. Preantral follicles were then classified according to the stage of development. Preantral follicles were classified individually either as morphologically normal; as Type 1 degenerated follicles (only the oocyte was degenerated); or as Type 2 degenerated follicles (when degeneration occurred at both oocyte and granulosa cells). The total examined was 235 primordial, 195 primary and 101 secondary follicles. The distribution of degenerated follicles as primordial, primary and secondary follicles was 8.5, 14.3 and 16.8%, respectively. When Types 1 and 2 degenerated follicles were pooled, secondary follicles were significantly more degenerated than primordial and primary follicles. When degeneration Types 1 and 2 was compared in each follicular class, a higher (P<0.05) percentage of Type 1 degeneration was observed in primordial and primary follicles. Conversely, secondary follicles were significantly more affected by Type 2 degeneration. When the follicular classes were taken together, a significantly higher percentage of Type 1 degenerated preantral follicles was observed when compared with Type 2 degenerated follicles (P<0.05). In conclusion, a low percentage of degenerated preantral follicles was observed and secondary follicles were more affected by degeneration than primordial follicles. Thus, primordial follicles constitute a large and potentially valuable source of oocytes for reproductive programs after in vitro growth and maturation

Use of ethyl-trinexapac in upland rice cultivars

The lodging of some rice cultivars, at harvest time, can cause significant losses in grain yield. The use of plant regulators is one of the alternatives to reduce lodging, however, information on that subject are still scarce. This study aimed to evaluate the use of ethyl-trinexapac doses (0 g ha-1, 50 g ha-1, 100 g ha-1, 150 g ha-1, and 200 g ha-1), at the floral differentiation stage, in rice cultivars with different types of plants (Caiapó - traditional; BRS Primavera and BRS Soberana - intermediate; and IAC 202 - modern), in order to evaluate grain development and yield. The experiment was carried out in Selvíria, Mato Grosso do Sul State, Brazil, during the 2007/2008 growing season. It was observed that the application of 50 g ha-1, 100 g ha-1, and 150 g ha-1 of ethyl-trinexapac, during the floral differentiation stage of the Caiapó, BRS Soberana, and BRS Primavera cultivars, respectively, decreased plants height and eliminated lodging; it was not necessary to use growth regulator for the IAC 202 cultivar, due to its lack of lodging; the application of 50 g ha-1 and 150 g ha-1 of ethyl-trinexapac, during the floral differentiation stage, improved grain yield for the Caiapó and BRS Primavera cultivars, respectively, and the 100 g ha-1 dose interfered little in the BRS Soberana cultivar

An evolutionary paradox on threadsnakes: Phenotypic and molecular evidence reveal a new and remarkably polymorphic species of Siagonodon (Serpentes: Leptotyphlopidae: Epictinae) from Amazonia

Threadsnakes are known for their conserved external morphology and historically controversial systematics, challenging taxonomic, biogeographic and evolutionary researches in these fields. Recent morphological studies—mostly based on µCT data of the skull and lower jaw—have resolved systematic issues within the group, for instance leading to the description of new taxa or re-positioning little-known scolecophidian taxa in the tree of life. Herein we describe a new polymorphic species of the genus Siagonodon from Amazonia based on morphological (external, osteology and hemipenis) and molecular data, and provide the first hemipenial description for the genus. We also reassign Siagonodon acutirostris to the genus Trilepida based on osteological data in combination with molecular evidence. The new species described represents an evolutionary paradox for scolecophidians because the species displays a remarkable variation in the shape of the snout region that is otherwise always highly conserved in this clade. Finally, this study reinforces the importance of protected areas as essential in maintaining vertebrate populations, including those that are not yet formally described