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Search Results: 1 - 10 of 18165 matches for " Altamir Frederico;Carvalho "
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Correla??es can?nicas: II - análise do rendimento de gr?os de feij?o e seus componentes
Coimbra, Jefferson Luís Meirelles;Guidolin, Altamir Frederico;Carvalho, Fernando Irajá Felix de;Azevedo, Roni de;
Ciência Rural , 2000, DOI: 10.1590/S0103-84782000000100005
Abstract: thirty two bean genotypes (phaseolus vulgaris l.) were evaluated in lages/sc, brazil, on the influence of seven characters of agronomic importance on the production of grains per unit of area. the experiment, in randomized blocks with four repetitions, was driven in the off season period in the agricultural year of 1995/96. this work aimed to estimate the intensity the association between the primary and secondary components of grain yield. the first group of variables (primary) was constituted by the number of grains per pod, number of pods per plant and the weight of a thousand grains. the second group (secondary) consisted of number of days from emergency to flowering, number of days from emergency to harvesting point, plant stature and the first pod insertion point. for the analysis of canonical correlations, the importance of secondary agronomic characters was evident in the traits number of pods per plant and grains per pod and also the influence of both on the final grain yield. therefore, the coefficients of canonical correlations indicate that, in programs bean genetic improvement programs, to increase the production of grains one should select plants with larger number of pods per plant in order to obtain plants with higher stature and longer cycle.
Parametros genéticos do rendimento de gr?os e seus componentes com implica??es na sele??o indireta em genótipos de feij?o preto
Coimbra, Jefferson Luís Meirelles;Guidolin, Altamir Frederico;Carvalho, Fernando Irajá Felix de;
Ciência Rural , 1999, DOI: 10.1590/S0103-84781999000100001
Abstract: thirty two genotypes of black bean (phaseolus vulgaris l.) had their field performance evaluated in the agricultural year of 1996/97 in lages/sc. the influences of three characters of agronomic importance on the production of grains for unit per area were scored. a completely randomized block design was used with four replications. the objective of the study was to estimate some genetic and phenotypic parameters of black bean. the direct selection revealed values of genetic gains superior to the ones obtained through indirect selection. the weight of a thousand grain (pmg) contributed to genetic progress through indirect selection than, the number of pods per plant (nlp) and the number of grains per pod (ngl). the results demonstrated that the tested black bean genotypes had a wide genetic variability, which was an indication of excellent germplas sources. the employment of estimates of genetic parameters such as genetic variance between pure lines and the heritability coefficient may be used as a powerful tool for bean breeders
Caracteriza??o da diversidade genética entre acessos crioulos de feij?o (Phaseolus vulgaris L.) coletados em Santa Catarina por marcadores RAPD
Carvalho, Márcio Fonseca de;Crestani, Maraisa;Farias, Francine Lunardi;Coimbra, Jefferson Luís Meirelles;Bogo, Amauri;Guidolin, Altamir Frederico;
Ciência Rural , 2008, DOI: 10.1590/S0103-84782008000600005
Abstract: the knowledge of the genetic diversity through the divergence among the genotypes allows the organization of the germplasm, sampling and efficient utilization in breeding programs. the objective of this study was to analyze the dissimilarity among germplasm collected in santa catarina state, stored in udesc germplasm active bank of common bean, and of three cultivars ('pérola', 'scs 202-guará' e 'brs valente'), using rapd markers. 21 decamer-primers that allowed the visualization of 96 bands were used, and 41 (42.7%) presented polymorphism among the studied accesses, resulting in a band range of 650 to 2000pb. the dissimilarity was calculated using the sorensen-dice coefficient and the grouping analyses were derived from upgma. the accesses were separated in two main groups, with wide dissimilarity when compared with the divergence inside each group. these two groups indicate the possible center of domestication, middle-american or andean, of the accesses in this study. the dissimilarity among the cultivars evaluated ('scs 202-guará', 'brs valente' e 'pérola') was small (0.15), if compared with the divergence among the accesses of the germplasm bank (0.65). the smaller dissimilarity among the studied accesses (baf63 and baf04) was 0.02. the results reinforce the need of new collection expeditions, which will increase the representation of the genetic variability of the remaining bean landraces in santa catarina state.
Reflexos da intera??o genótipo X ambiente e suas implica??es nos ganhos de sele??o em genótipos de feij?o (Phaseolus vulgaris L.)
Coimbra, Jefferson Luís Meirelles;Guidolin, Altamir Frederico;Carvalho, Fernando Irajá Felix de;Coimbra, Silvana Manfredi Meirelles;Hemp, Silmar;
Ciência Rural , 1999, DOI: 10.1590/S0103-84781999000300009
Abstract: the importance of grains of legume plants for human feeding, specially black beans (phaseolus vulgaris l.), has stimulated the breeders to select genotypes with high grains yield potential and wide adaptability to different conditions of cultivation in southern brazil. the present work aimed at evaluating the reflexes of the genotype x environment interaction and its implications in the genetic gains of different selection approaches. the results revealed that the component of the interaction between genotype and environment overestimates the prediction of genetic parameters such as genetic variance and heritability. differences among these estimates were observed apparently due to a high percentage of the complex part of the interaction. besides, the genetic gains obtained with the direct selection were always superior to the indirect response. comparatively, the pair of environments 1x3 revealed correlated response inferior and of opposite sign to the other estimates for the other pairs of environments studied. the first environment was the one which accumulated the higher interaction genotype by environment. it can be concluded that the interaction component has great relevance in the estimates of genetic gains, evidencing that this influence should be considered in the selection and in the recommendation of specific genotypes of bean breeding programs.
Análise de trilha. I: análise do rendimento de gr?os e seus componentes
Coimbra, Jefferson Luís Meirelles;Guidolin, Altamir Frederico;Carvalho, Fernando Irajá Felix de;Coimbra, Silvana Manfredi Meirelles;Marchioro, Volmir Sergio;
Ciência Rural , 1999, DOI: 10.1590/S0103-84781999000200005
Abstract: thirty two bean accesses (phaseolus vulgaris l.) were evaluated for the influence of eight characters of agronomic importance the production of grains for unit of area, in lages/sc. the experiment, in randomized blocks with four repetitions, was conducted during the period off-season in the agricultural year of 1996/97. this work aimed estimating the degree of association between grain yield and its secondary components. the first group of variables (primary) was constituted by the number of grains per pod, number of pods per plant, weight of a thousand grains and the population of plants (pop). the second group (secondary), was constituted by the number of days between emergence and flowering (fl), number of days between emergence and harvesting point (mc), plant stature (ep) and the height of first pod insertion (pil). for the analysis of the trail coefficient, the direct and indirect effects of primary characters nlp and pmg were characterized and evaluated, revealing the large direct effects associated with the high correlation. the nlp was highly influenced by plants of shorter cycle and higher stature. the trail coefficients allow to point out that the largest direct effects on the yield of grains nlp are mainly associated to pmg, ngl and cycle of the plant.
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.
Uso ou abuso em testes de compara??es de média: conhecimento científico ou empírico?
Bertoldo, Juliano Garcia;Coimbra, Jefferson Luís Meirelles;Guidolin, Altamir Frederico;Miqueloto, Aquidauana;Toaldo, Diego;
Ciência Rural , 2008, DOI: 10.1590/S0103-84782008000400039
Abstract: the objective of this research was to verify which are the main mistakes and the successes in the application of mean comparison tests in scientific studies, demonstrating viable alternatives in the sense of increasing the impartiality of the results obtained by researchers. one of the researcher's largest challenges is the interpretation of the obtained results in a trustworthy way. in spite of the concern of most researchers with the data analysis, many times certain disregard is observed in the interpretation of the results. thus, the incorrect application of statistical tests leads the researchers to publish information not completely reliable. one hundred and forty-eight papers dealing with one or more than one factor were evaluated. all of them are related to the crop production major area, published from 2002 to 2006, in the 'ciência rural', a brazilian scientific journal. most of the studies (72%) were classified as incorrect due to the abuse of means comparison tests. in addition, only 4% and 24% were classified respectively as partially correct and correct.
Resposta de híbridos de milho cultivados em diferentes épocas à popula??o de plantas e ao despendoamento
Sangoi, Luís;Guidolin, Altamir Frederico;Coimbra, Jefferson Luís Meirelles;Silva, Paulo Regis Fereira da;
Ciência Rural , 2006, DOI: 10.1590/S0103-84782006000500004
Abstract: current maize hybrids are more tolerant to the increasing of plant population than the hybrids used in the past. it is possible that modern hybrid's better adaptation to crowding is related to the lower apical dominance of the tassel over the ear. this experiment was aimed at evaluating the evolution on maize hybrids commercially released in different times the increase in plant population and at detecting if this progress is related to the reduction of apical dominance. the experiment was carried out in lages, sc, during the 1999/2000 and 2000/2001 growing seasons. a split-split plot design was used. three plant populations were tested in the main plots: 50,000, 75,000 and 100,000pl ha-1. four hybrids commercially released in the 60's, 70's, 80's and 90's, respectively, were assessed in the split plots. each hybrid was analyzed with preserved tassels and with tassel removed at booting in the split-split plot. the trials were installed in 10/30/1999 and 11/02/2000. grain yield was assessed using the variance and regression analyzes. the hybrid commercially released in the 90's (ag 9012) was more demanding in plant population to maximize grain yield when the conditions were favorable to yields higher than 10,000kg ha-1 (1999/2000). at this scenario, tassel interference on ear development was small. on the other hand, grain yield of all tested hybrids was increased by tassel removal under a lower yield plateau (2000/2001).there was no association between higher tolerance to crowding and greater response to detasseling, indicating that the tested hybrid higher endurance to dense stands was not related to the reduction in apical dominance of the tassel over the ear.
A desuniformidade de emergência reduz o rendimento de gr?os de milho
Merotto Junior, Aldo;Sangoi, Luis;Ender, Marcio;Guidolin, Altamir Frederico;Haverroth, Hector Silvio;
Ciência Rural , 1999, DOI: 10.1590/S0103-84781999000400004
Abstract: high maize grain yields are related to a fast, complete and regular plant emergence. this experiment was carried out in lages, sc, brazil, with the objective of evaluating the effects of an uneven plant emergence on maize grain yield at different plant populations. a split plot design was used, with the main plots disposed in randomized complete blocks. four plant populations, equivalent to 40,000, 60,000, 80,000 and 100,000 pl.ha-1 were tested in the main plots. different levels of unevenness in plant emergence were analyzed in the split plots by varying the sowing dates of adjacent hills inside each as it follows: 1 - even emergence (0-0-0-0); 2 - unevenness of 12 days (0-12-0-12); 3 - unevenness of 19 days (0-19-0-19); 4 - unevenness of 12 and 19 days (0-12-19-0-12-19). the increase in plant population up to 76,500 pl.ha-1 enhanced grain yield to 12,900kg.ha-1. at this plant population, the difference in yield grain per hectare among treatments with even and uneven emergence was nearly 2,900kg. this indicates that under similar productivity levels replanting maize may be on economically viable option. besides reducing grain yield, uneven emergence also limited maize response to the increment in plant population.
Incidência e severidade de doen?as de quatro híbridos de milho cultivados com diferentes densidades de plantas
Sangoi, Luís;Ender, Márcio;Guidolin, Altamir Frederico;Bogo, Amauri;Kothe, Daniel Marcelo;
Ciência Rural , 2000, DOI: 10.1590/S0103-84782000000100003
Abstract: modern maize hybrids have greater yield potential than cultivars used in the past, particularly under stressful conditions such as high plant population and water deficit. it is possible that the yield advantage presented by modern genotypes is partially due to their better ability to resist major maize diseases. this experiment was carried out to evaluate the incidence and severity of maize leaf, stem, and ear diseases on hybrids usually grown in southern brazil, under different plant populations. a split plot design was used, with the main plots disposed in randomized complete blocks. three plant populations, equivalent to 50,000, 75,000 and 100,000pl ha-1, were tested in the main plot. the hybrids ag 12, ag 28, ag 303 and ag 9012, which were cultivated expressively in the 60's, 70's, 80's and 90's, respectively, were tested in the split plot. the enhancement in plant population promoted increases on the incidence of stem diseases caused by fusarium moniliforme, colletotrichum graminicola e diplodia maydis, especially on ag 12 and ag 28, contributing to decrease their stem standability at harvesting. the hybrid ag 9012 had lower incidence and severity of ear diseases caused by fusarium moniliforme e diplodia maydis, regardless of plant population. the hybrid ag 9012 did not express lower severity levels of leaf diseases in relation to the older hybirds used in the trial.
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