Navegando por Autor "Cruz, Cosme D."

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Avaliação de cultivares de pêssego e nectarina em Araponga, Minas Gerais
(Revista Ceres, 2000-07) Albuquerque, Alejandra S.; Bruckner, Claudio H.; Cruz, Cosme D.; Salomão, Luiz C. C.
A coleção de germoplasma de pessegueiro da UFV foi avaliada na localidade de Araponga, MG. Avaliaram-se características fonológicas das plantas (floração, colheita e tempo entre natação e colheita) e de qualidade dos frutos (diâmetro, relação comprimento/diâmetro, peso, relação polpa/caroço, firmeza e umidade da polpa, relação entre o teor de sólidos solúveis e acida total titulável do suco e coloração vermelha da casca). De acordo com os objetivos do projeto de melhoramento local (frutos de qualidade para consumo in natura, umidade e adaptação à baixa disponibilidade de frio hibernal), foram considerados promissores para hibridações os cultivares Alô Doçura, Aurora l, Aurora 2, Campinas l, Centenária, Centenário, Cristal, Josefina, Maravilha, Marli, Okinawa, Ouromel, Premier, Régis, Relíquia, Real, Rubro Sol, Setembro, Talismã e tropical.
Comparative study of different molecular markers for classifying and establishing genetic relationships in Coffea canephora
(Plant Systematics and Evolution, 2012-11-03) Ferrão, Luís Felipe V.; Caixeta, Eveline T.; Souza, Flávio de F.; Zambolim, Eunize M.; Cruz, Cosme D.; Zambolim, Laércio; Sakiyama, Ney S.
The genetic variability characterization of the accessions of the germplasm collection, using molecular markers, is being applied as a complementary strategy to the traditional approaches to redefine the plant genetic resources. In this study, we compared the informativeness and efficiency of the molecular markers RAPD, AFLP and SSR in the analysis of 94 accessions of Coffea canephora germplasm held by the breeding program of the Brazilian Agricultural Research Corporation (Embrapa), Rondônia State, Brazil. For this, we considered the marker’s discriminatory power and level of polymorphism detected and also the genetic relationships and clustering (dendrogram) analysis. The RAPD marker yielded low-quality data and problems in the discrimination of some accessions, being less recommended for genetic studies of C. canephora. The SSRs had a higher level of information content and yielded high-quality data, while AFLP was the most efficient marker system because of the simultaneous detection of abundant polymorphism markers per few reactions. Our results indicate that AFLP and SSR, allies to the intrinsic characteristics of each technique, are the most suitable molecular markers for genetic studies of C. canephora. However, the choice of AFLP or SSR in the species characterization should be made in agreement with some characteristics that are discussed in this work.
The effects of encoding data in diversity studies and the applicability of the weighting index approach for data analysis from different molecular markers
(Plant Systematics and Evolution, 2014-02-11) Ferrão, Luı́s Felipe V.; Caixeta, Eveline T.; Cruz, Cosme D.; Souza, Flávio F. de; Ferrão, Maria Amélia G.; Maciel-Zambolim, Eunize; Zambolim, Laércio; Sakiyama, Ney S.
The use of molecular markers to study genetic diversity represents a breakthrough in this area, because of the increase in polymorphism levels and phenotypic neutrality. Codominant markers, such as microsatellites (SSR), are sensitive enough to distinguish the heterozygotes in genetic studies. Despite this advantage, there are some studies that ignore this feature and work with encoded data because of the simplicity of the evaluation, existence of polyploids and need for the combined analysis of different types of molecular markers. Thus, our study aims to investigate the consequences of these encodings on simulated and real data. In addition, we suggest an alternative analysis for genetic evaluations using different molecular markers. For the simulated data, we proposed the following two scenarios: the first uses SNP markers, and the second SSR markers. For real data, we used the SSR genotyping data from Coffea canephora accessions maintained in the Embrapa Germplasm Collection. The genetic diversity was studied using cluster analysis, the dissimilarity index, and the Bayesian approach implemented in the STRUCTURE software. For the simulated data, we observed a loss of genetic information to the encoded data in both scenarios. The same result was observed in the coffee studies. This loss of information was discussed in the context of a plant-breeding program, and the consequences were weighted to germplasm evaluations and the selection of parents for hybridization. In the studies that involved different types of markers, an alternative to the combined analysis is discussed, where the informativeness, coverage and quality of markers are weighted in the genetic diversity studies.
Identification and in silico analysis of the Citrus HSP70 molecular chaperone gene family
(Genetics and Molecular Biology, 2007) Fietto, Luciano G.; Costa, Maximiller D. L.; Cruz, Cosme D.; Souza, Alessandra A.; Machado, Marcos A.; Fontes, Elizabeth P. B.
The completion of the genome sequencing of the Arabidopsis thaliana model system provided a powerful molecular tool for comparative analysis of gene families present in the genome of economically relevant plant species. In this investigation, we used the sequences of the Arabidopsis Hsp70 gene family to identify and annotate the Citrus Hsp70 genes represented in the CitEST database. Based on sequence comparison analysis, we identified 18 clusters that were further divided into 5 subgroups encoding four mitochondrial mtHsp70s, three plastid csHsp70s, one ER luminal Hsp70 BiP, two HSP110/SSE-related proteins and eight cytosolic Hsp/Hsc70s. We also analyzed the expression profile by digital Northern of each Hsp70 transcript in different organs and in response to stress conditions. The EST database revealed a distinct population distribution of Hsp70 ESTs among isoforms and across the organs surveyed. The Hsp70-5 isoform was highly expressed in seeds, whereas BiP, mitochondrial and plastid HSp70 mRNAs displayed a similar expression profile in the organs analyzed, and were predominantly represented in flowers. Distinct Hsp70 mRNAs were also differentially expressed during Xylella infection and Citrus tristeza viral infection as well as during water deficit. This in silico study sets the groundwork for future investigations to fully characterize functionally the Citrus Hsp70 family and underscores the relevance of Hsp70s in response to abiotic and biotic stresses in Citrus.
Molecular characterization and genetic diversity of the macaw palm ex situ germplasm collection revealed by microsatellite markers
(Diversity, 2016-10-13) Mengistu, Fekadu G.; Motoike, Sérgio Y.; Cruz, Cosme D.
Macaw palm (Acrocomia aculeata) is native to tropical forests in South America and highly abundant in Brazil. It is cited as a highly productive oleaginous palm tree presenting high potential for biodiesel production. The aim of this work was to characterize and study the genetic diversity of A. aculeata ex situ collections from different geographical states in Brazil using microsatellite (Simple Sequence Repeats, SSR) markers. A total of 192 accessions from 10 provenances were analyzed with 10 SSR, and variations were detected in allelic diversity, polymorphism, and heterozygosity in the collections. Three major groups of accessions were formed using PCoA—principal coordinate analysis, UPGMA—unweighted pair-group method with arithmetic mean, and Tocher. The Mantel test revealed a weak correlation (r = 0.07) between genetic and geographic distances among the provenances reaffirming the result of the grouping. Reduced average heterozygosity (Ho < 50%) per locus (or provenance) confirmed the predominance of endogamy (or inbreeding) in the germplasm collections as evidenced by positive inbreeding coefficient (F > 0) per locus (or per provenance). AMOVA—Analysis of Molecular Variance revealed higher (48.2%) genetic variation within population than among populations (36.5%). SSR are useful molecular markers in characterizing A. aculeata germplasm and could facilitate the process of identifying, grouping, and selecting genotypes. Present results could be used to formulate appropriate conservation strategies in the genebank. View Full-Text
Somaclonal variation on in vitro callus culture potato cultivars
(Horticultura Brasileira, 2004-04) Bordallo, Patricia N.; Silva, Derly H.; Maria, José; Cruz, Cosme D.; Fontes, Elizabeth P.
Synthetic seeds can be an alternative for those species in which botanical seeds are not viable. One of the major problems of in vitro plant cultivation is the high level of somaclonal variation. The most common factors affecting somaclonal variation are genotype, explant source, in vitro period and cultivation conditions in which the culture is established. In this work, calli were induced using leaf and stem explants of the commercial potato cultivars Achat, Baraka, Baronesa, Bintje, and Contenda in MS culture media supplemented with 1.65 mM of picloram and 11.5 mM of 2,4-D. Seventy and 90 days after induction, DNA samples of 40 calli were compared concerning the effects of the two explant (leaf and stem) and two growth regulator sources on five potatoes cultivars. A total of 20 arbitrary sequence primers were evaluated. The RAPD pattern generated by these primers suggested a high percentage of polymorphic fragments among the five genotypes, indicating a high level of genetic variation among cultivars. Cultivar Baronesa showed the highest number of polymorphic fragments for all treatments. The cultivar Contenda showed the smallest somaclonal variation, for most of the treatments, except for the treatment which consisted of stem explants, picloram (1.65 mM) application, and a 70-day period of callus formation. 'Contenda' is, therefore, the most suitable cultivar for synthetic seed production.