Elisa Serra Negra Vieira

Variabilidade genética em cultivares de soja determinada com marcadores microssatélites em gel de agarose

O objetivo deste trabalho foi avaliar a variabilidade genetica de cultivares de soja com marcadores microssatelites selecionados e caracterizados quanto a informatividade para uso em gel de agarose. O DNA de 23 cultivares de soja foi amplificado com 283 marcadores microssatelites em gel de agarose a 3%. Posteriormente, 53 marcadores que apresentaram polimorfismo facilmente detectavel nos geis de agarose foram utilizados na caracterizacao de 53 cultivares. Nessas cultivares foram detectados 124 alelos, com media de 2,34 alelos por loco, e os valores de conteudo de informacao polimorfica variaram entre 0,16 e 0,66, com media de 0,47. As frequencias alelicas variaram de 0,02 a 0,91, com media de 0,43. A distância genetica calculada variou de 0,02 a 0,73, com media de 0,47. A menor distância observada foi entre as cultivares CD201 e CD208, e a maior distância entre CD210 e BRSMT Uirapuru. Os marcadores utilizados possibilitaram a identificacao das 53 cultivares avaliadas. Os locos microssatelites de soja, avaliados em gel de agarose, apresentam elevada informatividade. E possivel detectar variabilidade significativa no germoplasma brasileiro de soja avaliado, mesmo entre cultivares elite, quando se usa marcadores moleculares microssatelites selecionados por sua informatividade.

Genetic variability in Brazilian wheat cultivars assessed by microsatellite markers

Wheat (Triticum aestivum) is one of the most important food staples in the south of Brazil. Understanding genetic variability among the assortment of Brazilian wheat is important for breeding. The aim of this work was to molecularly characterize the thirty-six wheat cultivars recommended for various regions of Brazil, and to assess mutual genetic distances, through the use of microsatellite markers. Twenty three polymorphic microsatellite markers (PMM) delineated all 36 of the samples, revealing a total of 74 simple sequence repeat (SSR) alleles, i.e. an average of 3.2 alleles per locus. Polymorphic information content (PIC value) calculated to assess the informativeness of each marker ranged from 0.20 to 0.79, with a mean of 0.49. Genetic distances among the 36 cultivars ranged from 0.10 (between cultivars Ocepar 18 and BRS 207) to 0.88 (between cultivars CD 101 and Fudancep 46), the mean distance being 0.48. Twelve groups were obtained by using the unweighted pair-group method with arithmetic means analysis (UPGMA), and thirteen through the Tocher method. Both methods produced similar clusters, with one to thirteen cultivars per group. The results indicate that these tools may be used to protect intellectual property and for breeding and selection programs.

Development of microsatellite markers for identifying Brazilian Coffea arabica varieties

Microsatellite markers, also known as SSRs (Simple Sequence Repeats), have proved to be excellent tools for identifying variety and determining genetic relationships. A set of 127 SSR markers was used to analyze genetic similarity in twenty five Coffea arabica varieties. These were composed of nineteen commercially important Brazilians and six interspecific hybrids of Coffea arabica, Coffea canephora and Coffealiberica. The set used comprised 52 newly developed SSR markers derived from microsatellite enriched libraries, 56 designed on the basis of coffee SSR sequences available from public databases, 6 already published, and 13 universal chloroplast microsatellite markers. Only 22 were polymorphic, these detecting 2-7 alleles per marker, an average of 2.5. Based on the banding patterns generated by polymorphic SSR loci, the set of twenty-five coffee varieties were clustered into two main groups, one composed of only Brazilian varieties, and the other of interspecific hybrids, with a few Brazilians. Color mutants could not be separated. Clustering was in accordance with material genealogy thereby revealing high similarity.

CD 117: nova cultivar de trigo de ampla adaptação

The wheat (Triticum aestivum L.) cultivar CD 117 was obtained by the Cooperativa Central de Pesquisa Agricola 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, Parana, Sao Paulo, Mato Grosso do Sul, Mato Grosso, Goias, 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%.

Embriogênese somática a partir de embriões imaturos em genótipos de milho

The establishment of a protocol for regenerating plants by tissue culture is the first step in breeding programs which have the objective of using genetic transformation on plants. The plant regeneration can be achieved either by organogenesis or embryogenesis. In the second case, the somatic embryogenesis depends on the identification of responsive genotypes which enhance the efficiency of the program. The aim of the present study was to identify maize genotypes with high capacity to produce somatic embryos and consequently regenerate maize plants. Eleven genotypes (inbreds and hybrids) were investigated in the present experiment. Under two-week periods, the cultures were obtained from immature embryos which were inoculated into growing medium N6 with 690mg L-1 of proline and 10mM of 2,4-D. Callis of type II, friable and embryogenic, were observed in the LD82025, CD308, and CML314 genotypes. After, they were submitted to the regeneration process and the best performance was achieved by the LD82025. No embryogenic callus was developed from CD307, CD304, OC-705, 105-B, and GU04328. In the present case, the inbred LD82025 is the most promising maize genotype for participating in a breeding program that will use the genetic transformation of maize plants.

Técnicas para superação da dormência de sementes de guanandi

O objetivo deste trabalho foi avaliar tipos de preparo de sementes de guanandi (Calophyllum brasiliense), com vistas a superacao da dormencia fisica e mecânica, e verificar a influencia da temperatura e do substrato sobre a germinacao. Foram avaliados tres substratos (papel, areia e vermiculita), duas temperaturas de germinacao (25 e 30oC) e quatro tipos de preparo das sementes: sementes integras; sementes nuas, sem tegumento e endocarpo; sementes com punctura no endocarpo, na regiao proxima ao eixo embrionario ou na regiao oposta ao eixo embrionario; e sementes cortadas a 1/3 da regiao oposta ao eixo embrionario. Foram realizados testes de vigor (indice de velocidade de germinacao e emergencia de plântulas em campo), e a curva de embebicao foi obtida para os diferentes tipos de preparo da semente. A retirada total do envoltorio (endocarpo e tegumento) e necessaria para a completa superacao da dormencia fisica e mecânica das sementes de guanandi. A germinacao das sementes deve ser realizada em substrato papel a temperatura de 30oC.

CD 150 - short wheat cultivar with high quality and high yield

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.

QUALIDADE SANITÁRIA E FISIOLÓGICA DE SEMENTES DE ARAUCÁRIA DURANTE ARMAZENAMENTO

Araucaria angustifolia is a species of ecological and social-economic importance in the southern Brazil region, but it is at risk of extinction. Its seeds are classified as recalcitrant, requiring storage under controlled temperature and humidity to obtain greater longevity. Another aspect is the seed health quality, which is impaired by high seed moisture content that causes fungus proliferation and may reduce germination and seedling quality. The objective of this study was to evaluate the physiological and sanitary quality of araucaria seeds treated with 0.5, 1 and 3 % of sodium hypochlorite (NaClO) and stored at different periods (2, 4, 6, 8 and 12 months). The seed quality was evaluated by germination, vigor and seed health tests. The disinfection of seeds, regardless of the concentration used, temporarily delayed the seed germinations, but did not negatively affect seedling emergence. After 12 months of storage, the seeds showed infection by Schizophyllum commune , which caused the reduction of the germination. The seeds treated with NaClO showed lower fungal incidence, especially Schizophyllum commune , ensuring the seed health quality during storage for 12 months. The treatment with NaClO positively favors the physiological quality of Araucaria seeds that will be stored for a period exceeding four months.

Critérios para condução do teste de tetrazólio em sementes de araucária

The objective of this work was to determine criteria for the conduction of tetrazolium test on araucaria (Araucaria angustifolia) seeds, with greater execution speed and detailed characterization of viability groups. Initially, germination and tetrazolium tests were conducted according to the Rules for Seed Testing for Araucaria spp. After that, more practical methods for carrying out the tetrazolium test were evaluated, without pre-wetting of the seeds and using excised embryos immersed directly in the tetrazolium solution; three concentrations of the solution (0.075, 0.2, and 0.5%), three staining periods (1, 2, and 4 hours), and two staining temperatures (30 and 40°C) were tested. The means obtained for each conducted test were compared by the Scott-Knott test, at 1% probability. The tetrazolium test may be effectively used through the excision of araucaria embryos and the direct immersion in the tetrazolium solution using the following combinations of concentration/period/temperature: 0.5%/2 hours/30°C, 0.075%/4 hours/40°C, or 0.5%/2 hours/40°C, allowing the classification of the seeds into two different viability groups (viable and unviable).

Variabilidade genética de Phakopsora pachyrhizi avaliada por meio de marcadores microssatélites

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.