Saturated salt accelerated aging and computerized analysis of seedling images to evaluate soybean seed performance.

ABSTRACT: Seed deterioration causes losses to seed companies during the storage. For researches, the challenge has been to develop techniques which improve the seed longevity as well as laboratory analysis methods required for evaluating the evolution of deterioration in storage. This study had the objective of determining the effectiveness of the accelerated aging test with a saturated NaCl solution and Seed Vigor Imaging System (SVIS) analysis in checking soybean seed physiological in comparison with the recommended vigor tests. Soybean seeds from the cultivars BRS 184 and M-Soy 7908 RR were used, each of them were represented by six lots and stored for six months under two environment conditions. Seed physiological quality was checked every two months in storage through germination evaluations, accelerated aging (different methods), tetrazolium test (vigor and viability) seedling emergence, and SVIS analysis. The tetrazolium test is the most advisable method for evaluating soybean seed quality during storage. The results of the saturated salt accelerated aging test with NaCl at 41 ºC for 72 or 96 hours and the SVIS evaluation are also both efficient for estimating the physiological potential of seeds. RESUMO: Deterioração em sementes provoca prejuízos para empresas sementeiras durante o armazenamento. Para os pesquisadores, o desafio tem sido buscar técnicas que visam aumentar a longevidade das sementes bem como métodos de análise laboratoriais exigidos para avaliar a evolução da deterioração no armazenamento. Este estudo teve o objetivo de avaliar a eficácia do teste de envelhecimento acelerado com solução saturada de NaCl e do uso do software Seed Vigor Imaging System (SVIS) para comparação do potencial fisiológico das sementes durante o armazenamento, em comparação com os testes de vigor existentes. Foram utilizadas sementes de soja das cultivares BRS 184 e M-Soy 7908 RR, representadas por seis lotes e armazenadas por seis meses, sob duas condições ambientais. Verificou-se o potencial fisiológico por meio de avaliações de germinação, envelhecimento acelerado (diferentes métodos), tetrazólio (vigor e viabilidade), emergência de plântulas e análise SVIS. O teste de tetrazólio é o mais sensível para avaliar o potencial fisiológico de sementes de soja durante o armazenamento. Além disso, os testes de envelhecimento acelerado em solução saturada de NaCl a 41 ºC durante 72 horas ou 96 horas e análise a partir do software SVIS foram eficazes para estimar o potencial fisiológico de sementes de soja

Mapping the potential yield of upland rice in Rondonia State.

The rice farming has a high socioeconomical importance for Brazilian population, and represents since the 1970?s, it is the main crop for agricultural borders opening. Aiming characterize the potential yield and to define the regions most favorable for growth upland rice, it was simulated the potential grain yield (PGY), potential evapotranspiration (ETP) and maximum transpiration (TRC) by anoriented process crop model. The simulations were based on cultivar BRSPrimavera, considering eight planting dates (Nov 1st, 10th, 20th, Dec 1st, 10th, 20th, 30th and Jan 9th), for 33 years of data weather (1980-2013), in seven locations at Rondônia state: Ariquemes, Cacoal, Guajara-Mirim, Ji-Paraná, Machadinho do Oeste, Porto Velho and Vilhena. The upland rice crop cycle ranged from 95 days from emergence (DAE) in Ariquemes to 99 DAE in Machadinho do Oeste. The PGY, ETP and TRC data set were spatialized for the region. Rondônia showed an average and standard deviation potential yield of 4393 and 477 kg ha-1. The average ETP was 584,8 mm/cycle, with variance of 1259.9 mm/cycle. Maximum and minimum values of ETP was found for Guajara-Mirim and Vilhena, planting dates of Nov 1st and Jan 9th, respectively. The spatialization of results demonstrated a trend of PGY reduction as the sowing date is delayed. The highest potential yield were found at Vilhena (4952.7 kg/ha) and Ariquemes (4461.4 kg/ha)

Irrigation efficiency simulation for common bean during dry season, in the municipality of Goiânia, Goiás.

Goiás State is considered the major common beans producer in the autumn/winter season. In this season, the common beans production is fully irrigated by Center Pivot. However, due to the water scarcity water, the water dispute among human consumption, power generation, industries and agriculture is increasing. Then, it is important to optimize their consumption in the agriculture. Crop models are excellent tools for that and were used in this study to simulate the irrigation efficiency during the winter season for two cultivars, Pérola and BRS Radiante. Five planting dates from April to August and five irrigation amounts (10, 15, 20, 25 and 30 mm) applied when the soil water content reaches 50% of field capacity (CC) were considered. For cultivar Pérola, longer cycle, the best irrigation efficiency was obtained at the end of planting season, in the month of August, for the fixed irrigation amounts of 20 and 25 mm respectively. In the other hand, for the short cycle cultivar, BRS Radiante, the best irrigation efficiency was obtained only at the begin of planting date season, April

Avaliação de modelos de estimativa de potássio.

O objetivo desse estudo foi avaliar um modelo de estimativa da concentração de potássio com base no modelo linear de VOGELER que considera três constantes a partir de dados coletados em campo. O trabalho foi conduzido na área experimental da Embrapa Mandioca e Fruticultura, localizada no município de Cruz das Almas. O solo da área é classificado como Latossolo Amarelo Álico. O experimento foi realizado em um solo cultivado com bananeira, espaçadas de 3,0 m entre fileiras duplas, 2,0 m entre fileiras simples e 2,5 m entre plantas. Os tratamentos consistiram na utilização de quatro dosagens de potássio (D1 = 0, D2 = 400, D3 = 800 e D4 = 1200 kg de K2O ha-1). O modelo tradicional de VOGELER com quatro parâmetros apresentou maior eficiência na estimativa de CEw em função da umidade CEa, além de resultar em melhor estimativa de potássio com o uso da técnica de TDR, em condições de campo

Caracterização do índice de pigmentos em videira Syrah cultivada em dois sistemas de condução no Submédio São Francisco, PE.

O objetivo deste trabalho foi avaliar e o índice relativo de clorofila em plantas de videira cultivadas em dois sistemas de conduçã

Uso do fogo em pastagens naturais.

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Life table analysis of Diaphorina citri (Hemiptera: Psyllidae) infesting sweet orange (Citrus sinensis) in São Paulo

An ecological life table for eggs and nymphs of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) was constructed with data obtained from orange orchards (Citrus sinensis Osbeck) in 2 regions of the State of São Paulo, over 4 generations in the period from XI-2006 to V-2007, comprising spring, summer, and fall seasons. Young growing shoots with D. citri eggs present were identifed, and live individuals were counted until adult emergence. No predatory arthropods were observed in association with D. citri eggs and nymphs during the study. The mean parasitism of fourth- and ffth-instar nymphs by Tamarixia radiata Waterston (Hymenoptera: Eulophidae) was 2.3%. The durations of the egg–adult period were similar among the 4 generations, ranging from 18.0 to 24.7 d (at mean temperatures ranging from 21.6 to 26.0 °C) and followed the temperature requirement models obtained in the laboratory for D. citri. However, survival from the egg to the adult stage for the same period varied considerably from 1.7 to 21.4%; the highest mortalities were observed in the egg and small nymphal (frst- to thirdinstar) stages, which were considered to be key phases for population growth of the pest.Uma tabela de vida ecológica foi construída para ovos e ninfas de Diaphorina citri Kuwayama (Hemiptera: Psyllidae) com dados obtidos em pomares de laranja (Citrus sinensis Osbeck) em 2 regiões do estado de São Paulo, com 4 gerações, no período de novembro de 2006 a maio de 2007, compreendendo as estações de primavera, verão e outono. Ramos jovens em crescimento com a presença de ovos de D. citri foram identificados e os indivíduos vivos foram contados até a emergência dos adultos. Nenhum predador foi observado associado a ovos e ninfas de D. citri durante o estudo. A taxa média de parasitismo de ninfas de quarto e quinto ínstares por Tamarixia radiata Waterson (Hymenoptera: Eulophidae) foi de 2.3%. A duração do período de ovo a adulto foi semelhante entre as quatro gerações, variando de 18.0 a 24.7 dias (com temperaturas médias de 21.6 a 26.0 °C) e seguiram os modelos de exigencias térmicas obtidas em laboratório para D. citri. Todavia, a sobrevivencia de ovo até o estágio adulto variou consideravelmente para o mesmo período, de 1.7 a 21.4%, sendo que as maiores mortalidades foram observadas nos estágios de ovos e ninfas pequenas (de primeiro a terceiro ínstares), as quais foram consideradas fases chaves para o crescimento populacional desta praga.info:eu-repo/semantics/publishedVersio

Annual dune plant communities in the Southwest coast of Europe

This study presents an updated sintaxonomic review of the annual communities from coastal dunes in the Southwest coast of Europe, specifically in the Iberian Peninsula, including both types: directly influenced by the sea salt spray and not affected by this influence. The floristic segregation of the different plant associations was obtained by statistical agglomerative processes (UPGMA, Unweighted Pair Group Method with Arithmetic Mean) plus principal coordinate analysis (PCoA) and discussed based on the interpretation of phytosociological tables. Three new communities in central western Portugal were found and are described: Pseudorlayo minusculae-Polycarpietum alsinifoli, Cerastio diffusae-Vulpietum fontqueranae and Omphalodo kunzinskyanae-Evacietum ramosissimae