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The objective of this study was to evaluate genetic stability by determining the meiotic index (MI) and pollen viability in F1RC2 segregating populations, obtained by the crosses between wheat commercial cultivars and synthetic wheat, aimed at introgression/genetic resistance. For MI, three ears were collected per genotype, before anthesis, and they were fixed in Carnoy’s solution. The cytological slides were prepared by crushing the anthers and staining with 1% acetocarmine, and the normal tetrads and the ones with micronuclei were observed under a light microscope. For pollen viability, the ears were collected at the stage of mature pollen grain. The methodological procedure was similar to that of the tetrads, evaluating the pollen grains as viable, with little starch, with two pores, different sizes and non-viable. The pollen grain size was measured by the Axion Vision software. All the segregating populations with MI above 90% and high pollen viability (above 85%) reflected a stable meiotic behavior. About the variation in size, the CIGM90.909/BRS 179 cross showed pollen grains with 58.43 μm and CIGM93.298/BRS Guamirim, 47.15 μm. According to the results, wheat segregating populations were considered meiotically stable and suitable for use in wheat breeding programs and for incorporation of new important genes. O objetivo do estudo foi verificar a estabilidade genética, determinando-se o Índice Meiótico (IM) e a viabilidade polínica em populações segregantes F1RC2, oriundas do cruzamento entre trigos sintéticos e cultivares comerciais de trigo, que visam introgressão/resistência genética. Para o IM, três espigas foram coletadas por genótipo, antes da antese, e fixadas em Carnoy. As lâminas citológicas foram preparadas pelo método de maceração com corante carmim acético 1%, observadas em microscópio ótico e analisadas tétrades normais e com micronúcleos. Para a viabilidade polínica, as espigas foram coletadas no estágio de grãos de pólen maduro. O procedimento metodológico foi semelhante ao das tétrades, avaliando-se: grãos de pólen viáveis, com pouco amido, com presença de dois poros, tamanhos diferentes e inviáveis. O tamanho dos grãos de pólen foi medido pelo programa Axion Vision. Todas as populações segregantes apresentaram IM acima de 90% e viabilidade polínica elevada (acima de 85%), refletindo comportamento meiótico estável. Quanto à variação no tamanho, o cruzamento CIGM90.909/BRS 179 apresentou grãos de pólen com 58,43 µm e CIGM93.298/BRS Guamirim, 47,15 µm. Com base nos resultados, as populações segregantes de trigo apresentam-se meioticamente estáveis e adequadas para seguirem em programas de melhoramento de trigo e incorporação de novos genes importantes.

Background Specific studies of Brazilian wheat storage on a commercial scale on the maintenance of wheat quality are required since the continental extension of Brazil has regions of different weather and the diversity of the storage network. This study aimed to evaluate the technological quality (physicochemical and rheological), sanitary quality (insect, fungi, and mycotoxins), and dry matter loss of wheat stored in a metal silo in a commercial storage unit. Two dynamic samples, collected during loading and unloading of wheat in silos, and 4 static samples, collected using a commercial pneumatic grain sampler, were used in this study. Results Silo temperature was higher than 20 °C during the summer season. The temperature was approximately 15 °C from June to December and provided excellent conditions for grain aeration, which resulted in the maintenance of wheat quality, with no changes in hectoliter weight and rheological properties of wheat (falling number, wet gluten, and stability). The effect of Alternaria spp. (~220) and Aspergillus flavus (~7) infection on wheat did not differ statistically during the storage period, although a slight increase in A. flavus infection was noted in February (summer season). The wheat mycotoxins: deoxynivalenol, zearalenone, aflatoxins, and ochratoxin A were not detected during the studied storage period. Finally, dry matter reduced by approximately 0.4% after storage period, approximately 0.013% per month. Conclusion The management practices and climate conditions in southern Brazil provided excellent conditions for grain aeration at ambient air temperature and led to the maintenance of wheat quality during the post-harvest period. This article is protected by copyright. All rights reserved.

The wheat cultivar ‘BRS 331’ was developed by Embrapa. It results from an interspecific cross between wheat and maize by double-hapolid method. ‘BRS 331’ shows solid stem in the base of the plant, short leaves and super-early cycle to maturity. It is classified as bread wheat in all of the regions that is recommended in the States of Rio Grande do Sul, Paraná and Santa Catarina, Brazil.

A cultivar de trigo 'BRS Marcante' foi desenvolvida pela Embrapa, envolvendo um híbrido F1 do cruzamento entre as linhagens PF 980533 e PF 970227 com a cultivar 'BRS Guamirim', realizado em telado, na Embrapa Trigo, no inverno de 2003. As gerações segregantes foram conduzidas pelo método genealógico e a linhagem resultante, nomeada de PF 080310. A cultivar caracteriza-se pela sua ampla capacidade de adaptação às condições de cultivo do sul do Brasil, pelo bom potencial de rendimento de grãos e qualidade industrial da classe Pão The wheat cultivar 'BRS Marcante' was developed by Embrapa, as a result a cross between F1 hybrid between lines PF 980533 and PF 970227 with 'BRS Guamirim' and carried out in a green-house of Embrapa Wheat, on 2003 winter season. The segregate generations were conducted by genealogic method and the genotype resulted was named PF 080310. It has wide adaptation ability to south Brazilian conditions, high grain yield potential and belongs to Bread Class

O objetivo deste trabalho foi avaliar o desempenho de 12 combinações de três clones de painel (PB 311, PB 314 e RRIM 600) com quatro clones de copa (F 4512, MDF 180, IAN 6158 e IAN 6543) de seringueira cultivados no sudoeste do Estado do Mato Grosso. Utilizou-se o delineamento experimental de blocos ao acaso, com quatro repetições. Foram avaliados: produção de borracha seca, percentagem de plantas aptas à sangria, secamento de painel, estado nutricional, teor de borracha seca, plasticidade Wallace (P0 e P30), índice de retenção de plasticidade e viscosidade Mooney. As combinações das copas IAN 6543 e MDF 180 com os painéis PB 311, RRIM 600 e PB 314 apresentaram estado nutricional adequado, com produtividade de borracha seca acima de 1,41 Mg ha-1 por ano. O clone de copa IAN 6158 propiciou, em oito anos, as maiores quantidades de plantas aptas à sangria. As combinações painel/copa apresentaram baixa incidência de secamento de painel, exceto PB 311 x IAN 6158. As borrachas das 12 combinações painel/copa apresentam boa resistência à degradação térmica e alta retenção de plasticidade. Made available in DSpace on 2019-11-07T18:08:29Z (GMT). No. of bitstreams: 1 a16v26n2.pdf: 304946 bytes, checksum: 1619b588dc5bf2173ccfd1fdac1c2c56 (MD5) Previous issue date: 2001

Occurrence of Rice Blast in Barley leaves in Rio Grande do Sul, Brazil Magnaporthe grisea is reported for the first time affecting barley leaves in the state of Rio Grande do Sul, in experimental plots and in farmers fields in Victor Graeff county and surroundings. A brusone, causada pelo fungo Magnaporthe grisea (T.T. Hebert) M.E. Barr (anamorfo Pyricularia grisea Sacc.), foi constatada pela primeira vez na cultura de cevada (Hordeum vulgare L.) no Brasil em 1998 (Anjos & Charchar, Fitopatol. Bras. 25:205. 2000), no Distrito Federal afetando folhas da planta, cujos sintomas foram descritos como lesoes elipticas com centro de cor cinza e margem de cor marrom. Em 2001 e 2002, registrou-se sua ocorrencia afetando espigas nos estados de Goias, Minas Gerais e tambem no Rio Grande do Sul (Lima & Minella, Fitopatol. Bras. 28:207. 2003), cujos sintomas foram caracterizados por morte da porcao superior da espiga no ponto de infeccao no raquis e lesao preta brilhante nesse. Em 2005, a brusone em espigas de cevada foi observada, novamente, no Rio Grande do Sul em ensaios e lavouras no municipio Victor Graeff e arredores. Observou-se nas folhas sintomas similares aos de brusone descritos em cevada (Figura 1A). Na Embrapa Trigo, no Laboratorio de Fitopatologia, apos incubacao das folhas com sintomas em câmara umida, constatou-se nas lesoes a presenca de conidios em formato semelhante a pera, hialinos, com ate tres celulas, caracteristicas inerentes a conidios de Pyricularia. Realizou-se isolamento do fungo em meio de cultura BDA conforme Anjos & Charchar (2000). Plantas de cevada, cultivar BR 2, de aproximadamente 30 dias foram pulverizadas com uma suspensao de conidios na concentracao de 1,0 X 105 esporos mL-1 e mantidas em câmara umida no escuro por 24 horas a temperatura de 28 oC. Os primeiros sintomas da doenca foram registrados 48 horas apos a inoculacao. As dimensoes dos conidios produzidos em câmara umida foram de 10 μm de largura e 30-40 μm de comprimento. O re-isolamento do microorganismo a partir das lesoes produzidas nas folhas inoculadas (Figura 1B) comprovou a ocorrencia de P. grisea afetando folhas de cevada no estado do Rio Grande do Sul. Recebido 13 Dezembro 2006 Aceito 16 Marco 2007 FB 6134 FIG. 1 Folhas de cevada (Hordeum vulgare) com sintomas causados por Pyricularia grisea A. Sintomas em folha em condicoes naturais; B. Sintomas observados na cv. BR 2 apos inoculacao. A B

In the 2001 and 2002 crop seasons, barley (Hordeum vulgare L.) spikes showing symptoms similar to wheat (Triticum aestivum L.) and rice (Oryza sativa L.) blast were collected in commercial fields in the states of Rio Grande do Sul, Minas Gerais, and Goias, Brazil, as well as in experimental plots grown by the National Wheat Research Center (Embrapa Trigo) in the counties of Passo Fundo and Tapera, RS. The characteristic symptoms such as spike tip death (Figure 1A) and bright black spots of the rachis,were associated with pear-shaped, hyaline conidia, of up to three cells, 27.06-34.44 μm long and 9.84-12.3 μm wide, inherent characteristics of the fungus Pyricularia grisea (Cooke) Saccardo synonym P. oryzae Cavara [Tel.: Magnaporthe grisea (Hebert) Barr]. Attempting to confirm this etiology, an isolation was made on potato dextrose agar (PDA), with incubation at 22 ± 2 C and 12 h under light. Microorganism sporulation was obtained according to Anjos & Charchar (Fitopatologia Brasileira 25:205. 2000). Spikes of barley BR 2 were inoculated with a spore suspension (2.5 x 10 spores ml). Two inoculation procedures were used: sprinkling spore suspension and applying drop suspension on the rachis in two opposite spikelets. Plants were kept for 24 h in a humid chamber made from semitransparent, dark polyethylene bags, in the greenhouse. The spikes were sprayed with distilled water in the morning and in the afternoon for three consecutive days to keep them wet. Characteristic disease symptoms were recorded from the twelfth day onwards (Figure 1B). Inoculation by spraying resulted in the total death of most spikes. The microorganism isolated from inoculated spikes showed characteristics of P. grisea, confirming Koch′s postulates. Pyricularia grisea affecting barley spikes in Brazil is hereby reported for the first time. FIG. 1 Barley (Hordeum vulgare) spikes affected by Pyricularia grisea: A) Symptoms in spikes under natural conditions; B) Symptoms observed in cv. BR 2 after inoculation.

Synthetic wheat is developed by crossing tetraploid species ( Triticum turgidum , AABB) with a diploid species ( Aegilops tauschii , DD), followed by chromosome duplication through the use of colchicine to restore the resultant sterile hybrid to a fertile hexaploid plant. The main importance of producing synthetically improved wheat is to increase their genetic variability and to incorporate genes that code for resistance to biotic and abiotic stressors. This study aimed to evaluate the presence of micronuclei (MN) and the meiotic index (MI) in the tetrad phase in synthetic wheat accessions and cultivars ( Triticum aestivum ) stored at the Germplasm Bank of Embrapa Trigo (Brazil), in order to identify and select genetically stable accessions for plant improvement. Five plants were collected by genotype, prior to anthesis, and the tissues were fixed in Carnoy solution. Cytological slides were prepared by the smash method, and the cells were dyed with 1% acetocarmine and observed under an optical microscope. Presence of MN was observed in all genotypes analyzed, and variability of genetic stability was reported in the two years of analysis. In 2014, the highest MI of synthetic wheat accessions was 96.86% and the lowest was 46.32%. In 2015, the highest MI was 96.60% and the lowest was 47.96%. Based on the results, some genotypes were considered meiotically stable and suitable for use in wheat breeding programs. RESUMO: Trigos sintéticos são resultados do cruzamento entre uma espécie tetraploide ( Triticum turgidum, AABB) e uma espécie diploide ( Aegilops tauschii , DD) originando um híbrido estéril, seguido por duplicação cromossômica, por meio de colchicina, para restabelecer um trigo hexaploide fértil. A principal importância do uso de trigos sintéticos no melhoramento é que possibilitam aumentar a variabilidade genética, bem como introgredir genes de resistência a estresses bióticos e abióticos. O presente estudo teve como objetivo avaliar a presença de micronúcleos (MCN) e índice meiótico (IM) na fase de tétrades, em acessos de trigos sintéticos e cultivares testemunhas ( T. aestivum ), armazenadas no Banco de Germoplasma da Embrapa Trigo, a fim de selecionar os acessos estáveis geneticamente e disponibilizar ao melhoramento. Cinco plantas por genótipos, na fase anterior à antese, foram coletadas e fixadas em solução Carnoy. As lâminas citológicas foram preparadas pelo método de maceração e a coloração das células com carmim acético 1%. As observações foram em microscópio óptico. Observou-se a presença de micronúcleos em todos os genótipos analisados e foi encontrado variabilidade quanto à estabilidade genética nos dois anos de análises. Em 2014, o percentual máximo de IM dos acessos de trigos sintéticos foi de 96,86% e o mínimo de 46,32%. Em 2015, o percentual de IM máximo foi de 96,60% e o mínimo de 47,96%. Com base nos resultados, alguns genótipos foram considerados meioticamente estáveis e, poderão ser utilizados em programas de melhoramento genético de trigo.

In wheat breeding, several strategies are applied to improve grain yield. Annually, a great number of cultivars of different origins are crossed. The plants derived from these segregating populations are exposed to the most diverse possible stresses to develop new cultivars with maximum technical and economic efficiency and generate improvements to maximize the economic-environmental sustainability of plantations, while maintaining or increasing the yield potential. Made available in DSpace on 2020-09-18T04:38:34Z (GMT). No. of bitstreams: 1 AWN-VOL-66-p8-11pdf.pdf: 379271 bytes, checksum: d9ef470b0050ff60aa934ed4cce7fed3 (MD5) Previous issue date: 2020