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| Registros recuperados: 5.438 | |
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| Montaldo,Hugo H.; Meza-Herrera,Cesar A.. |
| Recent developments in molecular biology and statistics have opened the possibility of identifying and using genomic variation and major genes for the genetic improvement of livestock. Information concerning the basis of these techniques and their applications to the genetic improvement of animals is reviewed. Main marker molecular marker systems in animals (RFPL and microsatellites), genome maps, methods for detecting marker major gene linkages and use of marker assisted selection, genetic fingerprinting and mixture models based on segregation analysis are analyzed. The characteristics where the application of marker assisted selection can be more effective are those that are expressed late in the life of the animal, or controlled by a few pairs of genes.... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000200004 |
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| Daza,Camilo. |
| It is well known that the number of researchers in Biotechnology in Latin America and the Caribbean is too small to cope with the needs of research and to successfully confront the number of short and long-term problems. The United Nations University created its Biotechnology Program for Latin America and the Caribbean, UNU/BIOLAC, and the results of the efforts aiming to the promotion of a shared sense of direction within the region´s scientific community are presented and discussed herein. |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000200005 |
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| Ortiz,Rodomiro. |
| This article reviews some of the highlights of modern plant biotechnology and discusses the potential applications of biotechnology in the betterment of farming systems in the next millennium. Plant biotechnology will facilitate the farming of crops with multiple durable resistance to pests and diseases, particularly in the absence of pesticides. Likewise, transgenes or marker-assisted selection may assist in the development of high yielding crops, which will be needed to feed the world and save land for the conservation of plant biodiversity in natural habitats. Hence, crops should be engineered to meet the demands and needs of consumers. The genetic base of crop production can be preserved and widen by an integration of biotechnology tools in... |
| Tipo: Journal article |
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| Ano: 1998 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34581998000300005 |
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| Simioni,Carine; Schifino-Wittmann,Maria Teresa; Paim,Nilton Rodrigues. |
| A population of 513 hybrids of Leucaena leucocephala (4x) and L. diversifolia ssp. diversifolia (4x), that is being analyzed for several morphological and agronomical characteristics, aiming at selecting cold tolerant plants, was also analyzed for floral color. A model of additive dominant inheritance (pink color dominant over white color, or presence versus absence of pigment, and the number of dominant alleles present determining the intensity of the pink color) is proposed. The action of two independent locus sets is also suggested, one for the male (with two main structural genes) and another for the female floral organs (one main structural gene). It is suggested that an undetermined number of regulatory genes affect color expression. |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000300013 |
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| Dematteis,Massimiliano. |
| Chromosomes of 12 Vernonia species (Asteraceae) from South America were studied. First counts were reported for: V. alpestris Gardn. (n = 17), V. chalybaea Mart. ex DC. (2n = 32), V. cotoneaster Less. (2n = 30), V. fruticulosa Mart. ex DC. (n = 16) and V. lithospermifolia Hieron. (n = 10, 2n = 20). Furthermore, in V. aurea Mart. ex DC. (2n = 32), V. mollissima D. Don (n = 32) and V. saltensis Hieron. (2n = 64) numbers different from those reported in the literature were found. Karyotypes were described for some species. V. aurea contains 24m + 8sm chromosomes, V. chalybaea contains 22m + 10sm chromosomes, V. cincta Griseb. 36m + 16sm + 8st and V. cotoneaster 18m + 12sm. The basic chromosome numbers x = 10, 14, 15, 16 and 17 were confirmed for South... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000300016 |
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| Penna,Julio C. Viglioni; Verhalen,Laval M.; Kirkham,M.B.; McNew,Ronald W.. |
| The objectives of this study were to adapt a screening method previously used to assess seedling drought tolerance in cereals for use in cotton (Gossypium hirsutum L.) and to identify tolerant accessions among a wide range of genotypes. Ninety genotypes were screened in seven growth chamber experiments. Fifteen-day-old seedlings were subjected to four 4-day drought cycles, and plant survival was evaluated after each cycle. Three cycles are probably the minimum required in cotton work. Significant differences (at the 0.05 level or lower) among entries were obtained in four of the seven experiments. A "confirmation test" with entries previously evaluated as "tolerant" (high survival) and "susceptible" (low survival) was run. A number of entries duplicated... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000400023 |
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| Almeida,Fernanda S. de; Sodré,Leda M.K.. |
| Genetic variability of three Pimelodidae species, Pimelodus maculatus, Iheringichthys labrosus, and Pinirampus pirinampu, collected at one site in the Tibagi River, was comparatively analyzed using protein data for six systems which code 15 loci in liver, muscle, and heart. The proportion of polymorphic loci (<img src="http:/img/fbpe/gmb/v21n4/21n4a14.jpg" alt="21n4a14.jpg (768 bytes)" align="middle">) for P. maculatus, I. labrosus, and P. pirinampu was 13.33, 20, and 6.67%, respectively, and mean heterozigosity was 6, 8.3, and 4.3%. The genetic identity value (I) was 0.32 between P. maculatus and I. labrosus, 0.37 between P. maculatus and P. pirinampu, and 0.58 between I. labrosus and P. pirinampu. This value suggests that these two latter species... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000400014 |
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| Subacius,Sandra Maria Rodrigues; Bussab,Wilton de Oliveira. |
| Variations observed in 5S rRNA base compositions are almost entirely due to fixation of point mutations. As a consequence, 5S rRNA size has remained relatively constant during evolution and, therefore, dependencies among the four bases can be predicted. In order to characterize the nature and to determine the degree of such dependencies, correlation analysis followed by principal component factorial analysis was conducted on a large sample of 5S rRNA sequences. The results show that the purine and pyrimidine contents tend to remain constant, so that A + G = Kpur and C + U = Kpyr. The composition of the four bases expressed now by Kpur/Kpyr relationships is also constant (Ks). These relationships imply that the behavior of the mutations in the variable... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000200014 |
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| Campinhos,Eduardo N.; Peters-Robinson,Ingrid; Bertolucci,Fernando L.; Alfenas,Acelino C.. |
| We used allozyme markers to estimate the amount of natural hybridization between Eucalyptus grandis and E. urophylla in a 7.4-hectare commercial hybrid-seed orchard planted in Espírito Santo, Brazil. This orchard was planted in 1982 using a honeycomb design, with each hexagonal plot containing one E. grandis tree surrounded by six E. urophylla trees. There were 267 replicated hexagonal plots in the orchard. Seeds were harvested from the E. grandis clone only. The multilocus outcrossing rate estimated for the E. grandis clone averaged 70.2%, ranging from 33.0 to 99.0% among individual trees. Contaminant pollination, inferred from progeny genotypes containing alleles not present in the seven parental clones, accounted for 14.4% of the hybrid seed.... |
| Tipo: Info:eu-repo/semantics/article |
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| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000300014 |
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| Registros recuperados: 5.438 | |
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