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| Registros recuperados: 109 | |
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| Ballve,Rosa M.L.; Medina-Filho,Herculano Penna; Bordignon,Rita. |
| Broadness of leaf petiole wing (WB) was investigated as a morphological marker for screening hybrids of the very narrow-winged species Citrus limonia and C. sunki with broad-winged species C. aurantium and C. sinensis. Controlled polinizations produced over 500 reciprocal hybrids with potential in the ongoing rootstock breeding program identified by the Pgi-1 and Prxa-1 isozyme loci. Measurement ratios WB/leaf length, WB/leaf broadness and WB/petiole length identified 86 to 91% of the reciprocal hybrids produced. However, visual classification of WB was an equally efficient but much easier and faster method. It can be very useful in breeding programs when large number of plants have to be screened or when isozyme, RFLP or RAPD laboratories are not... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000400023 |
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| Grisolia,Cesar Koppe; Ferrari,Iris. |
| The herbicide metolachlor was evaluated for genotoxic potential. Metolachlor did not induce micronuclei in mice, however at 40 mg/kg it significantly decreased the percentage of polychromatic erythrocytes, which is a cytotoxic effect. Metolachlor did not induce chromosomal aberrations in human lymphocytes in vitro, but 2.0 mug/ml culture medium resulted in cytotoxicity, decreasing the mitotic index significantly. The indirect exposure test was carried out by adding plasma from metolachlor-pretreated rats to the human lymphocyte cultures. There was no indication of clastogenicity by metolachlor metabolites. On the other hand, plasma of cyclophosphamide-pretreated rats had a significant clastogenic effect |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000300009 |
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| Mutation induction breeding through gamma ray seed treatment (22 krad) was used to obtain earliness in the soybean cultivar Paraná. Plants flowering earlier than Paraná were selected at the M3 generation. Eight mutant lines were isolated by further selections through several generations and tested in four yield trials carried out in 85/86 (Piracicaba) and 86/87 (Piracicaba, Sertãozinho and Assis) in São Paulo State. The following data were taken in these trials: number of days to flowering, yield, total plant height and height to pod insertion, flower color, pod pubescence and seed and plant growth type. Two of the mutants are of agronomic interest because they were, on average, seven to 10 days earlier in maturity than the control in all trials. Except... |
| Tipo: Info:eu-repo/semantics/other |
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| Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000100009 |
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| Bean (Phaseolus vulgaris) lines P.I. 207262 and AB 136, both resistant to delta and kappa races of Colletotrichum lindemuthianum, were crossed with Michelite, Dark Red Kidney, and Perry Marrow, susceptible to both races, and with Cornell 49-242, resistant to delta and susceptible to kappa. F1 and F2 reactions demonstrated that P.I. 207262 carries duplicate dominant genes for resistance to the delta race; AB 136 carries a dominant gene. These resistance genes are independent of the Are gene from Cornell 49-242. With respect to the kappa race, F1 and F2 data showed that the resistance controlled by P.I. 207262 and by AB 136 depends on a single dominant gene. Complementary factors were involved with AB 136 resistance to the delta race and with P.I. 207262... |
| Tipo: Info:eu-repo/semantics/other |
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| Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000100011 |
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| Filippi,Marta C. de; Prabhu,A.S.. |
| Seven sources of resistance to the two predominant races IB-1 and IB-9 of the rice blast pathogen Pyricularia grisea were selected based on leaf blast reaction in tests conducted under controlled greenhouse conditions. Crosses involving resistant and susceptible parents were made to study the inheritance of the disease reaction for different sources of resistance. The F1 and F2 progenies of all crosses, including backcrosses to resistant and susceptible parents, were tested for reaction to leaf blast. The data showed that resistance is controlled by one to three genes that segregate independently in most of the donors. Non-allelic interaction among resistance genes, including dominant epistasis, was identified. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Blast resistance; Rice; Pyricularia grisea. |
| Ano: 1996 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551996000400012 |
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| Interphase cytogenetics, utilizing fluorescence in situ hybridization (FISH) techniques, has been successfully applied to diffuse and solid tissue specimens. Most studies have been performed on isolated cells, such as blood or bone marrow cells; a few have been performed on cells from body fluids, such as amniotic fluid, urine, sperm, and sputum. Mechanically or chemically disaggregated cells from solid tissues have also been used as single cell suspensions for FISH. Additionally, intact organized tissue samples represented by touch preparations or thin tissue sections have been used, especially in cancer studies. Advantages and pitfalls of application of FISH methodology to each type of specimen and some significant biological findings achieved are... |
| Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000100018 |
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| Intra and interspecific variability was measured in the genus Lycopersicon for the traits: productivity rate (PR, total number of regenerated shoots/total number of cultures), regeneration percentage (%R, number of cultures regenerating shoots or primordia/total number of cultures) and callus percentage (%C, number of cultures only producing callus/total number of cultures). Leaf explants from various genotypes of L. esculentum, L. esculentum var. cerasiforme, L. pimpinellifolium and L. peruvianum were placed on Murashige and Skoog (Physiol. Plant. 15: 473-493, 1962) medium + 0.175 mg/l IAA + 2.25 mg/l BA. Significant differences among species and among genotypes within the same species were found, while genotypes from different species showed similar... |
| Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000100014 |
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| Penteado,Maria Isabel de O.; García,Pedro; Pérez de la Vega,Marcelino. |
| Isozyme patterns and their genetic control in three Centrosema species are described. Seven isozymatic systems (aspartate aminotransferase, glucose-6-phosphate isomerase, phosphoglucomutase, anodal peroxidase, malate dehydrogenase, 6-phosphogluconate dehydrogenase, and isocitrate dehydrogenase) were studied in 18 populations and several breeding lines of C. acutifolium, C. brasilianum and C. pubescens, using starch gel electrophoresis techniques. All systems, except glucose-6-phosphate isomerase, are described for the first time in these species. A total of 17 isozyme loci were scored; this represents the largest set of Mendelian loci known up to now in Centrosema species. Isozyme polymorphism and variability within and between populations and species were... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000300015 |
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| A new viviparous mutant of maize (Zea mays L.), associated with genetic instability and designated viviparous-12 (vp12), was identified in a synthetic Tuxpeño adapted to tropical regions. In the present work, the linkage group of this new locus was determined. Progenies of inbred line L477 segregating for the vp12 mutant were crossed with waxy-marked reciprocal translocation stocks. The phenotypic frequencies of the wx and vp12 mutants were analyzed in F2 progenies. The results demonstrated that the Viviparous-12 locus of maize is located on the long arm of chromosome 6. |
| Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000100013 |
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| Silva,Ivana Tramontina da; Del Lama,Marco Antonio. |
| Five bovine milk protein polymorphisms were studied in Zebuine cattle raised in Brazil, through horizontal electrophoresis on starch gel containing urea and 2-mercaptoethanol, using basic and acidic buffer systems. Allelic frequencies for <FONT FACE="Symbol">a</FONT>-La, <FONT FACE="Symbol">b</FONT>-Lg, <FONT FACE="Symbol">a</FONT>S1-Cn, <FONT FACE="Symbol">b</FONT>-Cn and <FONT FACE="Symbol">k</FONT>-Cn loci were estimated in six Gyr herds (N = 283), six Guzerat herds (N = 205), one Nelore herd (N = 17) and one Sindi herd (N = 22), all from São Paulo or Minas Gerais State, Brazil. Genotypic frequencies observed for each locus and breed studied are in accordance with the assumption of genetic... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000400011 |
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| Lopes-Cendes,Iscia; Teive,Hélio G.A.; Cardoso,Francisco; Viana,Erika M.; Calcagnotto,Maria E.; Costa,Jaderson C. da; Trevisol-Bittencourt,Paulo C.; Maciel,Jayme A.; Rousseau,Marylene; Santos,André S.; Araújo,Abelardo Q.C.; Rouleau,G.A.. |
| Machado-Joseph disease (MJD) is a form of autosomal dominant spinocerebellar ataxia first described in North-American patients originating from the Portuguese islands of the Azores. Clinically this disorder is characterized by late onset progressive ataxia with associated features, such as: ophthalmoplegia, pyramidal and extrapyramidal signs and distal muscular atrophies. The causative mutation is an expansion of a CAG repeat in the coding region of the MJD1 gene. We have identified 25 unrelated families segregating the MJD mutation during a large collaborative study of spinocerebellar ataxias in Brazil. In the present study a total of 62 family members were genotyped for the CAG repeat in the MJD1 gene, as well as 63 non-MJD individuals (126 normal... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000400026 |
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| Genetic distances among cacao cultivars were calculated through multivariate analysis, using the D2 statistic, to examine racial group classification and to assess heterotic hybrids. A 5 x 5 complete diallel was evaluated. Over a five-year period (1986-1990), five cultivars of the S1 generation, pertaining to the Lower Amazon Forastero and Trinitario racial groups and 20 crosses between the corresponding S0 parents were analyzed, based upon five yield components - number of healthy and collected fruits per plant (NHFP and NCFP), wet seed weight per plant and per fruit (WSWP and WSWF), and percentage of diseased fruits per plant (PDFP). The diversity analysis suggested a close relationship between the Trinitario and Lower Amazon Forastero groups. A... |
| Tipo: Info:eu-repo/semantics/other |
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| Ano: 1997 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000100012 |
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| Registros recuperados: 109 | |
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