Abstract The objective of this work was to study the inheritance of soybean resistance to Soybean Steam Necrosis (SSN) and to map the resistance gene(s), using an F2 population from the cross between the soybean cultivars BRS 133 (resistant) and CD 206 (susceptible). A phenotypic evaluation was performed under controlled conditions, in a greenhouse. In a population of 114 F2 plants, 92 were resistant, and 22 were susceptible. The result is compatible with the inheritance of one dominant gene (χ2=1.98, P = 15.97%). Analysis of F1 and backcross populations confirmed the inheritance of one dominant gene. Bulk segregant analysis (BSA) was used as the mapping strategy. The resistance gene was mapped on chromosome 18 of the soybean genome, between markers Sat_308 and Satt303. This dominant gene is located on the same chromosome where the recessive SSN resistance gene rbc1 was mapped, at 8cM distance, and was named Rbc2.

Cultivar CD 1550 is well-suited for the wheat-growing regions 1 and 2 of Rio Grande do Sul, Santa Catarina and Paraná and 3 of Paraná. It has the characteristics of bread wheat and high gluten strength. The average potential yield is 3828 kg ha-1, 7% higher than that of the controls.

Cultivar CD 123 is recommendable for the wheat-growing regions 1, 2 and 3 of the States of Rio Grande do Sul, Santa Catarina and Paraná. It is a white flour wheat destined for production in cooler regions. The mean potential yield is 3514 kg ha-1, exceeding that of the control cultivars by 5%.

The cultivar CD 122 was tested in the wheat-producing regions VCU 1, 2 and 3, with an average grain yield of 3,527 kg ha-1 when fungicide-treated, exceeding the average of the control cultivars by 5%. CD 122 is resistant to leaf rust and was classified as bread wheat.

O objetivo deste trabalho foi avaliar as reações de resistência tipo I e tipo II à giberela em 28 cultivares de trigo em casa de vegetação. A inoculação de Fusarium graminearum foi realizada no estádio de florescimento. Para a resistência tipo I, a avaliação foi feita 21 dias após a inoculação. Foi determinada a severidade no estádio de espiga seca e a porcentagem de grãos giberelados. A avaliação da severidade foi feita pela porcentagem de espiguetas infectadas, no estádio de espiga verde atribuindo-se uma nota em uma escala linear de zero (nenhuma infecção) a 100 (100% de espiguetas infectadas). Para a resistência tipo II, as avaliações foram realizadas aos 7, 14 e 21 dias após a inoculação, contando-se as espiguetas com sintomas da doença, excluindo as duas espiguetas que foram inoculadas. As cultivares Frontana, BRS 177, BRS 179, BRS Umbu, BRS Camboim, Abalone, Ônix, Pampeano e Fundacep 30 apresentaram menor severidade da doença e menor porcentagem de grãos giberelados, demonstrando serem fontes de resistência tipo I. As cultivares BRS Guamirim, CD 120, Onix, Rubi, Fundacep 50, BRS 179, Pampeano, Abalone, CD 114, IPR 85, Safira, BRS Louro, CD 117, CDF 2002116, CD 115, BRS 177, CD 0529 e BRS Camboim apresentaram a menor área abaixo da curva de progresso da doença, demonstrando a presença da resistência do tipo II.

The aim of this study was to evaluate type I and type II resistance reactions to FHB for 28 wheat cultivars grown in a greenhouse. The inoculation of Fusarium graminearum was performed in the flowering stage. For type I resistance, the assessment was made at 21 days after inoculation. The disease severity was determined in the dry ear stage, as well as the percentage of scabby grains. The evaluation of disease severity was performed by using the percentage of infected spikelets in the green ear stage, assigning a score on a linear scale from zero (no infection) to 100 (100% infected spikelets). For type II resistance, assessments were performed at 7, 14 and 21 days after inoculation by counting the spikelets with symptoms, excluding the two inoculated spikelets. The cultivars Frontana, BRS 177, BRS 179, BRS Umbu, BRS Camboim, Abalone, Onyx, Pampeano and Fundacep 30 showed less disease severity and lower percentage of scabby grains, demonstrating thus potential to be sources of type I resistance. The cultivars BRS Guamirim, CD 120, Onyx, Ruby, Fundacep 50, BRS 179, Pampeano, Abalone, CD 114, IPR 85, Safira, BRS Louro, CD 117,CDF 2002116, CD 115, BRS 177, CD 0529 and BRS Camboim showed the smallest area under the disease progress curve, demonstrating thus type II resistance.

CD 121 is indicated for wheat regions with the classification Value for Cultivation and Use 1 and 2, in the states of PR, SC and RS. The cultivar is tolerant to leaf rust, has good agronomic traits, flour suited for cookie baking and an average grain yield of 3.622 kg ha-1.

O objetivo deste trabalho foi avaliar a reação de resistência tipo I à Giberela em 28 cultivares de trigo em experimentos conduzidos a campo, em duas épocas de semeadura (maio e junho). Em ambas as épocas foi utilizado o delineamento em blocos casualizados, composto por 28 tratamentos (cultivares) e quatro repetições. Para a dispersão do inóculo de Gibberela zeae na área foram utilizados grãos de trigo com peritécios do patógeno. Ao início do florescimento, em dias sem precipitação pluviométrica, a área experimental foi submetida ao molhamento de espigas com formação de neblina por 5 minutos consecutivos, a intervalos de 25 a 30 minutos. A avaliação da severidade da doença foi feita 21 dias após a inoculação, no estádio de espiga verde, atribuindo-se uma nota em uma escala linear de zero a 100, baseada na escala sugerida por Stack e McMullen. No estádio de espiga seca foi determinada a porcentagem de grãos giberelados. As cultivares Frontana, BRS 177, Safira e BRS Timbaúva estiveram no grupo com menor média de severidade da doença quando se consideram as duas épocas de semeadura conjuntamente. Na avaliação de grãos giberelados, as cultivares BRS 177, Onix, BRS Timbaúva, BRS Umbú, BRS Guamirim, CEP Raízes, CEP 50, CD 120 e CD 0529 estiveram, nas duas épocas, no grupo com menor média de incidência.

The aim of this study was to evaluate the type-I resistance reaction to FHB in 28 wheat cultivars in experiments conducted in the field, in two sowing dates (May and June). In both dates, a randomized block design was used, consisting of 28 treatments (cultivars) and four replicates. For dispersal of the inoculum Gibberela zeae in the area, wheat grains with the pathogen perithecia were used. At the beginning of flowering, on days without rainfall, the experimental area was subjected to wetting of ears by fog formation for 5 consecutive minutes, at intervals of 25 to 30 minutes. The disease severity was evaluated at 21 days after inoculation, in the stage of green ear, assigning a score on a linear scale from zero to 100, based on the scale suggested by Stack and McMullen. In the phase of dry ear, the percentage of scab grains was determined. The cultivars Frontana, BRS 177, BRS Safira and BRS Timbaúva were the group with the lowest mean disease severity when the two sowing dates were considered together. In the evaluation of scab grains, cultivars BRS 177, Onix, BRS Timbaúva, BRS Umbu, BRS Guamirim, CEP Raízes, CEP 50, CD 120 and CD 0529 were, in both dates, the group with the lowest mean incidence.

O objetivo deste trabalho foi avaliar a variabilidade genética da ferrugem-asiática-da-soja no Brasil, com uso de marcadores microssatélites. Populações de esporos de Phakopsora pachyrhizi coletadas nas regiões Sul, Sudeste e Centro Oeste do país foram submetidas à análise de variabilidade genética, avaliada por meio de marcadores microssatélites específicos para o fungo. Foram coletadas, também, populações de fungo em diversas variedades de soja em uma mesma localidade, incluindo populações com lesão "reddish-brown" (RB). Entre essas populações, não houve variabilidade. Tecidos com lesões RB não apresentaram esporos do fungo e não amplificaram com os marcadores específicos para P. pachyrhizi. A variabilidade genética entre as populações coletadas nas três regiões variou de 0 a 0, 36. Observou-se tendência de agrupamento das populações da região Sul e Centro Oeste do Brasil em grupos diferentes. A existência de variabilidade genética em populações de P. pachyrhizi é um indicativo de que a resistência genética vertical, conferida por genes únicos, é uma estratégia de risco para os programas de melhoramento genético que visam a resistência à ferrugem-asiática-da-soja no Brasil.

The objective of this work was to evaluate the genetic variability of Asian soybean rust in Brazil using microsatellite markers. Samples of Phakopsora pachyrhizi spores collected in the Southern, Southeastern, and Central West regions of Brazil were subjected to analysis of genetic variability, accessed with microsatellite markers specific for the fungus. Spores of the fungus were also collected in several soybean varieties in a same locality, including samples with reddish-brown (RB) lesions. Among these samples, there was no variability. Tissues with RB lesions did not contain spores of the fungus and did not amplify with the specific markers for P. pachyrhizi. Genetic variability among samples collected in the three regions ranged from 0 to 0.36. A tendency to cluster samples of the Southern and Central West regions of Brazil in different groups was observed. The existence of genetic variability in P. pachyrhizi spore populations indicates that vertical genetic resistance, provided by single genes, is a risky strategy for soybean breeding programs that aim resistance to Asian soybean rust.

O cultivar CD 120, desenvolvido pela Cooperativa Central de Pesquisa Agrícola (COODETEC) é recomendado para cultivo nos VCUs para as regiões 1 e 2 do Paraná, Santa Catarina e Rio Grande do Sul. É tolerante às principais doenças, à germinação pré-colheita, tem qualidade de trigo macio e é 6.5 % mais produtivo (3.678 kg ha-1) que a testemunha.

The cultivar CD 120, developed by the Cooperativa Central de Pesquisa Agrícola (COODETEC) is suitable for cultivation in the VCU wheat-producing regions 1 and 2 of the states of Paraná, Santa Catarina and Rio Grande do Sul. It is tolerant to the major wheat diseases and pre-harvest germination and has soft wheat quality and a 6.5 % higher grain yield (3.678 kg ha-1) than the control.

The industrial quality and lodging resistance of CD 150, a cross between CD104 and CD108, are high and the plant height is short. The average yield was 10 % higher than of the controls in the regions II, III and IV. It is suitable for cultivation in the states of PR, SP, MS and GO, MG, and DF.

A cultivar de trigo (Triticum aestivum L.) CD 117 foi obtida pela Cooperativa Central de Pesquisa Agrícola, por meio do cruzamento entre os genótipos PF 87373 e OC 938, a partir de uma linha selecionada na geração F6. Após dois anos de ensaios preliminares e cinco anos de avaliação em ensaios de valor de cultivo e uso, a cv. CD 117 foi indicada para cultivo no Rio Grande do Sul, Santa Catarina, Paraná, São Paulo, Mato Grosso do Sul, Mato Grosso, Goiás, Minas Gerais e Distrito Federal. Essa cultivar de trigo apresenta ampla adaptação, elevada qualidade industrial e rendimento médio de grãos de 3.877 kg ha-1, que supera em 6,3% a média das cultivares testemunhas.

The wheat (Triticum aestivum L.) cultivar CD 117 was obtained by the Cooperativa Central de Pesquisa Agrícola as a result of crossing the PF 87373 and OC 938 genotypes. One selected line from generation F6 originated the referred cultivar. After two years of preliminary assays and five years of value of cultivation and use trials, cultivar CD 117 was recommended for cultivation in the states of Rio Grande do Sul, Santa Catarina, Paraná, São Paulo, Mato Grosso do Sul, Mato Grosso, Goiás, and Minas Gerais and in the Distrito Federal, Brazil. This wheat cultivar has wide adaptation, high industrial quality and a mean grain yield of 3,877 kg ha-1, which exceeds the control cultivar mean yields in 6.3%.