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Search Results: 1 - 10 of 166676 matches for " Fernando Irajá Félix;Guidolin "
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Conseqüências da multicolinearidade sobre a análise de trilha em canola
Coimbra, Jefferson Luís Meirelles;Benin, Giovani;Vieira, Eduardo Alano;Oliveira, Ant?nio Costa de;Carvalho, Fernando Irajá Félix;Guidolin, Altamir Frederico;Soares, Adriana Pires;
Ciência Rural , 2005, DOI: 10.1590/S0103-84782005000200015
Abstract: the statistical multivariate analysis has a widespread use by researchers, creating a large demand for specific knowledge regarding its application concerning its assumptions and or limitations. in order to evaluate the degree of association among different characters of agronomic importance with an estimative reliable in biological terms, it is striking to quantify the multicolinearity among the studied variables. in addition, the types of statistical and mathematical models used in determining this linear dependence between classifying or independent variables may or may not be adequate for estimatives of biological parameters evaluated. the present work has as objective to present a critical evaluation on the degree of multicolinearity identified and evaluated on the path analysis performed on parts of a canola experiment. the results allow to postulate that path analysis application on the degree of severe multicolinearity produces results with no biological importance for the plant breeder. however, this limitation can be easily identified and corrected through path analysis with colinearity employing a constant (k) on diagonal axis of x?x matrix. the model of analysis with severe multicolinearity, however overestimated the single correlation coefficient values comparatively with the weak multicolinearity. even so, it may not be necessarily more precise, mainly regarding the evaluation of a restricted number of variables included in the analysis or an overlapping of the explainable variables.
Plant height reduction in populations of triticale (X triticosecale Wittmack) by induced mutations and artificial crosses
Pandini, Fábio;Carvalho, Fernando Irajá Félix de;Barbosa Neto, José Fernandes;
Brazilian Journal of Genetics , 1997, DOI: 10.1590/S0100-84551997000300020
Abstract: induced mutations by gamma radiation (0, 5, 10, 20 and 40 kr doses) and reciprocal crosses were tested as mechanisms of enhancing genetic variability for plant height in two triticale cultivars, br4 and embrapa18. the reciprocal crosses and all doses of radiation showed similar increase in genetic amplitude for this trait, being suitable for increasing variability in breeding programs. genotypes showed different responses as the gamma ray doses were increased, expressing shorter plant height. the decision of using induced mutations or artificial crosses depends on the resources available and the selection method to be used
Sele??o indireta para o incremento do rendimento de gr?os em aveia
Caier?o, Eduardo;Carvalho, Fernando Irajá Félix de;Floss, Elmar Luis;
Ciência Rural , 2006, DOI: 10.1590/S0103-84782006000400013
Abstract: genetic breeding must become more and more efficient to support the expansion in oat cropping area and the industrial utilization of oat grains, originating more productive genotypes in a shorter period of time. one of the improvement strategies that may be used to optimize the identification of potentially high productive genotypes is the indirect selection, if conducted through a character of easy measurement and high correlation with final productivity. thus, the objective of this work was to evaluate the efficiency of use of panicle weight factor as an indirect selection criterion to increment oat grain yield. segregating populations were conducted in f2 and f3 generations and submitted to three selection environments. at each site, over the best performing populations, a randomized sampling of 10 panicles was made. the samples were weighed and classified as superior or inferior according to their weight, in function of the standart deviation from average. the response to the selection was evaluated in the following generation, through phenotypic variables (panicle weight and grain yield) and genetic parameters in the three selection environments. panicles of superior weight originated also panicles of superior weight in the posterior generation in all three environments of selection. on the other hand, for the grain yield variable, the criterion of selection was effective in one environment only. the results demonstrated that indirect selection is a good selection tool for grain yield in oats, if carried out under responsive environments allowing the maximum expression of genotypes.
Resistência das plantas a moléstias fúngicas
Matiello, Rodrigo Rodrigues;Barbieri, Rosa Lia;Carvalho, Fernando Irajá Félix de;
Ciência Rural , 1997, DOI: 10.1590/S0103-84781997000100028
Abstract: plant resistance to fungic diseases is due to their genetic constitution and environmental factors. in breeding programs, one of the main objectives is to obtain high grainyield potenlial plants with resistance to the prevalent diseases. knowledge of genetic basis of resistance is importam to increase selection efficiency and due to the wide variability of fungi there is the necessity of using different strategies to reduce the probability of pathogen estabtishment in crops.
Importancia, problemas e perspectivas do melhoramento visando resistência a viroses em plantas
Barbieri, Rosa Lia;Carvalho, Fernando Irajá Félix de;Federizzi, Luiz Carlos;
Ciência Rural , 1995, DOI: 10.1590/S0103-84781995000300028
Abstract: virus diseases are a serious problem to agricuiture, can be a limitant factor to normal development of some crops. control measures, like vectors elimination, healthy material use, culture rotation and infected plants eradication, are only transient solutions. the more efficient approach for control involves plant breeding resistant to virus or its vector. reduced availability of resistance source can be increased through recombinant dna technology, which brings new breeding perspectives to virus resistant crops.
Implementa??o da sele??o recorrente no melhoramento de plantas autógamas através da macho-esterilidade
Canci, Paulo Cesar;Barbosa Neto, José Fernandes;Carvalho, Fernando Irajá Félix de;
Ciência Rural , 1997, DOI: 10.1590/S0103-84781997000300025
Abstract: the mechanism of pedigree system used in smallgrain cereals reduce genetic variability and recombination capacity due to the limited number of parent used in crosses. the increase in recombination through recurrent selection by maximizing number of crosses may be a solution for this problem. the use of male sterility may overcome the difficult of performing artificial crosses, supporting recurrent selection as a viable and important tool for autogamous crops breeding.
Marcadores moleculares e sua aplica??o no melhoramento genético de plantas
Bered, Fernanda;Barbosa Neto, José Fernandes;Carvalho, Fernando Irajá Félix de;
Ciência Rural , 1997, DOI: 10.1590/S0103-84781997000300026
Abstract: one of the most important factor in a plant breeding program is the capacity of the breeder to identify superior genotypes in a segregant population. the understanding of genetic relationships and combining ability among individuals is essential for parental selection. genetic markers are divided in morphological and molecular (enzyme or dna). they may help in the identification of individuals based on their genetic similarities. dna markers, as rflp and rapd, contribute to increase efficiency in plant breeding through linkage mapping and agronomic traits mapping. in addition, several researchers have pointed out the efficiency of these markers to characterize genotypes and to generate clusters of genetic similarity in germplasm from different species.
Capacidade combinatória como critério de eficiência na sele??o de genitores em feijoeiro
Kurek, Andreomar José;Carvalho, Fernando Irajá Félix de;Assmann, Isidoro Carlos;Cruz, Pedro Jacinto;
Pesquisa Agropecuária Brasileira , 2001, DOI: 10.1590/S0100-204X2001000400007
Abstract: the objective of the present work was to estimate the general combining ability (gca) and specific combining ability (sca) in the grain yield traits components through diallel cross of six bean (phaseolus vulgaris l.) genotype using the method 2, model b, suggested by griffing. the experiment was carried out in a complete randomized block design, with four replications, in 1998. the studied traits were: average weight grain; number of grain/pod; number of pod/plant and grain yield. the results of gca evidenced more importance than sca for all traits. according to the estimate of gca, the parent rudá showed the best values to the traits evaluated. in this way, the greater effect of sca for the general traits were to get in wrapping up cross with parent rudá x ci 967/2v, rudá x ft nobre and pérola x ci 9661, determining the importance of these parents for the species improvement programs.
Barbarasul: a high-yielding and lodging-resistant white oat cultivar
Fernando Irajá Félix de Carvalho,Antonio Costa de Oliveira,Igor Pirez Valério,Giovani Benin
Crop Breeding and Applied Biotechnology , 2009,
Abstract: The white-oat cultivar Barbarasul was developed by the Universidade Federal de Pelotas. It resulted from across between UPF18 and CTC5. It is adapted to the southern region of Brazil, with excellent grain yield potential, shortstature and high lodging tolerance.
Enchimento de sementes em linhas quase-isogênicas de trigo com presen a e ausência do caráter "stay-green"
Silva Simone Alves,Carvalho Fernando Irajá Félix de,Nedel Jorge Luís,Cruz Pedro Jacinto
Pesquisa Agropecuária Brasileira , 2003,
Abstract: O caráter "stay-green" (permanência da cor verde nas plantas) tem sido utilizado para reduzir a senescência em trigo, resultando no aumento funcional da área foliar, e, conseqüentemente, na eleva o da taxa e da dura o do enchimento da semente. O objetivo deste trabalho foi analisar a taxa de acúmulo de matéria seca e a dura o do período de enchimento da semente de linhas quase-isogênicas de trigo diferenciadas quanto à presen a e ausência do caráter "stay-green". O experimento foi conduzido no Centro Experimental da Palma, Pelotas, RS. Foram utilizadas quatro linhas quase-isogênicas: F6-SG e F6-SZ, no ano de 2000 e F7-SG e F7-SZ no ano 2001, com cinco repeti es. O caráter "stay-green" permitiu maior deposi o de reservas na semente na fase próxima do ponto de maturidade fisiológica. A dura o do período de enchimento da semente esteve associada ao acúmulo de matéria seca na semente, promovendo um maior peso médio da semente. Assim, o progresso do caráter taxa de enchimento da semente poderá ser obtido por meio de sele es de plantas com maior peso médio da semente.
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