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Progresso genético no melhoramento de algodoeiro no Estado de Mato Grosso. ; Genetic gain in cotton breeding in Mato Grosso state, Brazil.

Moresco, Edina Regina
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 06/06/2003 PT
Relevância na Pesquisa
46.22%
O melhoramento genético vegetal visa a obtenção de novos genótipos que representem algum tipo de ganho comparado aos genótipos em uso pelos agricultores. Para verificar se este objetivo está sendo alcançado, é necessário avaliar o desempenho do programa de melhoramento. Visando quantificar o progresso genético do programa da Embrapa para melhoramento de algodoeiro (Gossypium hirsutum L.) para as condições do estado de Mato Grosso, foram avaliados os dados de 12 anos de pesquisa para os caracteres produtividade de caroço (Kg/ha) e rendimento de fibra (%). Foram utilizadas três metodologias, sendo uma baseada em contrastes entre genótipos comuns em anos consecutivos (metodologia de Vencovsky et al., 1986) (VE), e duas baseadas em regressão linear de médias ajustadas (metodologias de Breseguello, 1998 e de Fonseca Júnior, 1997, respectivamente BR e FJ). Apenas as metodologias de regressão apresentaram estimativas significativas para o progresso genético. Para produtividade (Kg/ha), o progresso genético médio anual obtido pelas metodologias BR e FJ foram respectivamente 3,93% e 3,63%. Já para o caráter rendimento de fibra (%), o progresso genético médio anual para as mesmas metodologias foi respectivamente 0...

Progresso genético para produtividade do feijoeiro no programa de melhoramento do Instituto Agronômico (IAC) entre 1989 e 2007; Genetic gain for yield in the common beans breeding program at Agronomical Institute (IAC) from 1989 to 2007

Chiorato, Alisson Fernando
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 17/12/2008 PT
Relevância na Pesquisa
66.26%
No programa de melhoramento genético de feijoeiro do Instituto Agronômico (IAC) foram disponibilizadas até a presente data 38 cultivares de feijoeiro, contribuindo para o aumento da produtividade média no Brasil e, principalmente, no estado de São Paulo. Nesse contexto, o objetivo deste trabalho foi avaliar o progresso genético obtido para produtividade do feijoeiro com a pesquisa desenvolvida pelo IAC no período de 1989 a 2007. Foram avaliados 211 experimentos e 134 linhagens avançadas, distribuídas em 10 ciclos de seleção e conduzidas em três épocas de semeadura do feijoeiro. O progresso genético foi estimado para os períodos de pesquisa de 1989 a 1996 e de 1997 a 2007 em função das características dos experimentos de avaliação. No segundo período, estimou-se também o ganho por épocas de semeadura e tipos de tegumento. Nas análises, utilizou-se um modelo misto cujos efeitos foram obtidos por meio de quadrados mínimos ponderados, obtendo-se médias ajustadas em relação à produtividade média dos genótipos. Em seguida, a partir das médias ajustadas, realizou-se a análise de regressão linear para obtenção do progresso genético estimado por ciclo de seleção. No período entre 1989 a 1996, obteve-se um ganho relativo significativo de 1...

Use of progeny testing in beef cattle: Prediction of genetic gain in a Nelore Cattle Breeding Program

De Oliveira, H. N.; Lobo, R. B.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 207-214
ENG
Relevância na Pesquisa
56.12%
Genetic gains predicted for selection, based on both individual performance and progeny testing, were compared to provide information to be used in implementation of progeny testing for a Nelore cattle breeding program. The prediction of genetic gain based on progeny testing was obtained from a formula, derived from methodology of Young and Weiler (J. Genetics 57: 329-338, 1960) for two-stage selection, which allows prediction of genetic gain per generation when the individuals under test have been pre-selected on the basis of their own performance. The application of this formula also allowed determination of the number of progeny per tested bull needed to maximize genetic gain, when the total number of tested progeny is limited.

Genetic analysis for sooty mold resistance and heart of palm yield in Archontophoenix

Bovi,Marilene Leão Alves; Resende,Marcos Deon Vilela de; Sáes,Luís Alberto; Uzzo,Roberta Pierry
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2004 EN
Relevância na Pesquisa
56.02%
Archontophoenix palms, utilized both as ornamental species and as a source of high-quality heart of palm, are susceptible to sooty mold, a disease coupled with aphid infestation, which affects photosynthesis and causes unpleasant, darkish palm appearance. Scoring rates for sooty mold resistance and three growth traits were assessed under field conditions in 24 open-pollinated half-sibs families, 28 months after planting, aiming to identify genetic variability for sooty mold resistance; estimate genetic parameters for this trait and plant height, diameter and number of leaves; estimate genetic and phenotypic correlation for the four traits and evaluate selection methods for heart of palm production through multi-trait index selection based on growth traits. There were genetic differences among families for all traits. The low coefficient of variation for sooty mold (9.48%) indicates that the visual rating method adopted was effective and feasible for comparing aphid plus sooty mold infestation levels in Archontophoenix. Narrow sense heritability estimates were low and medium for growth traits (0.10, 0.26 and 0.26 for leaves number, plant diameter and height, respectively) and very high (0.91) for sooty mold resistance. Genetic correlation was found between sooty mold resistance and plant height. This positive relationship indicates that culling of very susceptible palms can be done possibily without interference in the follow up indirect selection for heart of palm yield. Some selection strategies were presented...

Genetic variation and realized genetic gain from rubber tree improvement

Gonçalves,Paulo de Souza; Aguiar,Adriano Tosoni da Eira; Costa,Reginaldo Brito da; Gonçalves,Elaine Cristine Piffer; Scaloppi Júnior,Erivaldo José; Branco,Roberto Botelho Ferraz
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2009 EN
Relevância na Pesquisa
55.98%
Breeding cycle in rubber extends to 20-30 years between pollination and yield assessment, distributed over three selection stages. Five hectares of small scale trial of rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg.], was established in the Northwestern region of São Paulo State, Brazil. The population comprises 98 clones mostly derived from intensively selected plus tree in the natural forest of rubber tree in the Amazon. Three open pollinated progeny tests were established in three experimental stations. Seedlings from 98 progenies including a commercial check (CC) were planted in each one of the three locations. Assessments were made when the plants were one, two and three years old. The variation among progenies for girth was highly significant in all locations examined. In the combined analysis of variance over three locations, differences among progenies were also detected, while progeny × location interaction effect was not significant. Narrow sense heritability estimates on individual tree basis (h i²) were variable depending on the characteristic, age of assessment and experimental location. Realized genetic gains were calculated for the plant characteristics at the age of three years, by comparing the performance of improved (selected) materials to unimproved materials (CC). The total genetic gain from the genetically tested first generation clone population at Votuporanga is estimated as 25% for girth...

Estimation of soybean genetic progress in the South of Brazil using multi-environmental yield trials

Lange,Cláudia Erna; Federizzi,Luiz Carlos
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2009 EN
Relevância na Pesquisa
56.03%
The success of a genetic breeding program in a certain period can be assessed by the genetic gain observed. Genetic progress can be estimated from the multi environmental trials (MET) data which are routinely carried out by annual species breeding programs for the assessment of new commercial cultivars. A data set of 20 years of MET of advanced soybean lines derived from four breeding programs was used to estimate and to compare the genetic gains obtained for three soybean maturity groups (early, medium and late) in four cropping regions of the State of Rio Grande do Sul. The estimated yield gains ranged from 0.0 to 71.5 kg ha-1 year-1 (3.49% per year), depending on the maturity group and region, which suggests that the genetic breeding effort does not have a similar effect among the maturity groups or benefit the regions equally. There was no evidence of genetic progress for the early maturity group in any of the four regions, whereas gains in Regions I and IV were comparatively greater than those in Regions II and III. The objectives of the soybean breeding program in the region should be redirected. Since not all the experimental lines used to estimate genetic gains were commercially released, the reported genetics gains were achieved by the breeding programs rather than those achieved by the cropping systems.

Genetic and environmental contributions to increased wheat yield in Minas Gerais, Brazil

Cargnin,Adeliano; Souza,Moacil Alves de; Fronza,Vanoli; Fogaça,Cláudia Martellet
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2009 EN
Relevância na Pesquisa
56.09%
Producers need wheat cultivars adapted to the predominant climate conditions of the end of the rainy period. Having this in mind, EPAMIG (Agriculture and Livestock Research Institute of Minas Gerais) has been developing a wheat genetic improvement program since 1976, and the estimates of the genetic improvement established by the breeding programs could be useful to quantify their efficiency. This study focused on the quantification of the genetic progress achieved by these improvement programs of dryland wheat in the Brazilian-savanna between 1976 and 2005. The efficiency of these programs was evaluated based on grain yield data of VCU (Value for Cultivation and Use) trials conducted at ten locations in the Minas Gerais State, Brazil. The mean estimated genetic progress for mean grain yield between 1976 and 2005 was 37 kg ha-1 year-1. The genetic yield gain in the study period indicates that the improvement programs of dryland wheat in the Brazilian-savanna are effective. Besides the marked contribution of genetic gain, the environmental and technological improvements were also relevant for the yield, accounting for 47.4% of the total progress in the period. The improvement programs of dryland wheat resulted in a genotype renovation rate of 35% over the years.

Genetic parameters and trends of morphometric traits of GIFT tilapia under selection for weight gain

Reis Neto,Rafael Vilhena; Oliveira,Carlos Antônio Lopes de; Ribeiro,Ricardo Pereira; Freitas,Rilke Tadeu Fonseca de; Allaman,Ivan Bezerra; Oliveira,Sheila Nogueira de
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2014 EN
Relevância na Pesquisa
56.18%
The main factor considered in breeding programs for fish is growth, which can be assessed in terms of a gain in either weight or body measurements. This study was undertaken to evaluate the morphometric traits of GIFT strain tilapia (Oreochromis sp.) selected for weight gain. The data set used contained information on 6,650 animals. The genetic values of 8,590 animals in a relationship matrix of five generations were predicted. The following morphometric measurements were evaluated: standard length; body depth and body width. Body area and volume were also calculated. Bi-character analyses involving morphometric traits were used to estimate (co)variance components. Heritability, larval and fingerling common environmental effects were estimated for each trait, together with the genetic and phenotypic correlations between traits. Bayesian procedures were utilised by Gibbs chains, and the convergence of the chains was tested using the Heidelberger and Welch method. Genetic trends were estimated by segmented regression of the fish breeding values of the generations considered in this study. Estimates of heritability (0.28 a 0.31) had moderate to high magnitudes for all traits. Genetic correlations between traits were all above 0.8, and the genetic gains were satisfactory from the third generation onwards. From the estimates of the genetic parameters and genetic gain the morphometric traits evaluated have good potential for selection.

Bias in the prediction of genetic gain due to mass and half-sib selection in random mating populations

Viana,José Marcelo Soriano; Faria,Vinícius Ribeiro; Silva,Admilson da Costa e
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 EN
Relevância na Pesquisa
66.17%
The prediction of gains from selection allows the comparison of breeding methods and selection strategies, although these estimates may be biased. The objective of this study was to investigate the extent of such bias in predicting genetic gain. For this, we simulated 10 cycles of a hypothetical breeding program that involved seven traits, three population classes, three experimental conditions and two breeding methods (mass and half-sib selection). Each combination of trait, population, heritability, method and cycle was repeated 10 times. The predicted gains were biased, even when the genetic parameters were estimated without error. Gain from selection in both genders is twice the gain from selection in a single gender only in the absence of dominance. The use of genotypic variance or broad sense heritability in the predictions represented an additional source of bias. Predictions based on additive variance and narrow sense heritability were equivalent, as were predictions based on genotypic variance and broad sense heritability. The predictions based on mass and family selection were suitable for comparing selection strategies, whereas those based on selection within progenies showed the largest bias and lower association with the realized gain.

Genetic gain for body weight, feed conversion and carcass traits in selected broiler strains

Schmidt,GS; Figueiredo,EAP; Ledur,MC
Fonte: Fundação APINCO de Ciência e Tecnologia Avícolas Publicador: Fundação APINCO de Ciência e Tecnologia Avícolas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2006 EN
Relevância na Pesquisa
66.15%
The Brazilian Swine and Poultry Research Center (Embrapa Suínos e Aves) maintains a chicken breeding program for meat production since 1985. Two control lines (LLc and PPc) are maintained, whereas two male lines (TT and ZZ) and three female lines (PP, VV and KK) have been selected. This paper reports the genetic gain after 15 generations of combined selection (mass and independent culling levels) in order to develop the commercial broiler stocks Embrapa 021 and Embrapa 022. Selection pressure has been exerted on weight gain, carcass traits and fertility. In addition, female lines have also been selected for egg production, whereas males have been selected for feed efficiency since 1992. All lines have been selected for breast area instead of carcass traits since 1999. The genetic gain was estimated as the deviation between selected lines and the respective unselected lines at 42 days of age. In female lines, body weight improved 504, 548 and 587 g; average breast area increased 27.60; 16.99 and 26.43 cm²; adjusted feed conversion (42-49 d) improved -1.46; -0.97 and 1.76 units, and egg production varied 6.99; 7.12 and -3.43% units for PP, VV and KK, respectively. In male lines, body weight improved 758 and 408 g; average breast area increased 31.95 and 19.38 cm²...

Genetic gain prediction of the third recurrent selection cycle in a popcorn population

Santos,Fabrício Santana; Amaral Júnior,Antonio Teixeira do; Freitas Júnior,Silvério de Paiva; Rangel,Ramon Macedo; Scapim,Carlos Alberto; Mora,Freddy
Fonte: Editora da Universidade Estadual de Maringá - EDUEM Publicador: Editora da Universidade Estadual de Maringá - EDUEM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
56%
Although Brazil has reduced its importation of popcorn grain in recent years, the availability of improved varieties is still rare. In order to improve a popcorn population and to estimate the prediction of genetic gains, the third cycle of intrapopulation recurrent selection was carried out. One hundred ninety two half-sib families were obtained from the second cycle of the UNB-2 U population and tested in a randomized complete block design with two replications within sets in two locations. The presence of statistical significance for sets for grain yield, poorly husked ear and broken plants proved the efficiency and the necessity for the use of the hierarchical statistical model by sets. Except for the poorly husked ear, there was significance for families within sets for the other evaluated traits, showing that there was sufficient genetic variability for exploitation in future cycles. Although the heritability for popping expansion was higher than for grain yield, the predicted genetic gain for the latter was superior to popping expansion because of the higher magnitude of the genetic standard deviation for grain yield. It is expected that in the fifth recurrent cycle, the first popcorn variety with yellow grains may be released for Rio de Janeiro State.

Genetic gain in an improvement program of irrigated rice in Minas Gerais.

SOARES, P. C.; MELO, P. G. S.; MELO, L. C.; SOARES, A. A.
Fonte: Crop Breeding and Applied Biotechnology, Viçosa, MG, v. 5, n. 2, p. 142-148, June 2005. Publicador: Crop Breeding and Applied Biotechnology, Viçosa, MG, v. 5, n. 2, p. 142-148, June 2005.
Tipo: Artigo em periódico indexado (ALICE)
EN
Relevância na Pesquisa
56.12%
An evaluation of the genetic improvement programme of irrigated rice of Minas Gerais (Brazil) estimated the genetic gain obtained in the 90s. Grain yield data of the advanced comparative trials of cultivars and lines of continuously flooded rice, conducted from 1990-91 to 2000-01, were used. The estimate of the genetic gain was obtained by the methodology of the adjusted means proposed by Breseghello (1998). The mean annual genetic gain in the 90s was 42.45+or-17.89 kg ha-1 (0.7% per year). The improvement programme proved auspicious for the development of lines that outmatched the controls. The mean of the cultivars released in the 90s did however not outstrip the mean of the elite lines, which were the genotypes with the highest means in this study and will be further evaluated in the ongoing programme.; 2005

Genetic resistance to soil chemical toxicities and deficiencies.

GOURLEY, L.M.; WATSON, C.E.; SCHAFFERT, R.E.; PAYNE, W.A.
Fonte: In: INTERNATIONAL CONFERENCE ON GENETIC IMPROVEMENT OF SORGHUM AND PEARL MILLET, 1996, Lubbock, Texas. Proceedings. Cali: INTSORMIL/ICRISAT, 1997. p.461-480. Publicador: In: INTERNATIONAL CONFERENCE ON GENETIC IMPROVEMENT OF SORGHUM AND PEARL MILLET, 1996, Lubbock, Texas. Proceedings. Cali: INTSORMIL/ICRISAT, 1997. p.461-480.
Tipo: Artigo em anais de congresso (ALICE)
EN
Relevância na Pesquisa
55.85%
Breeding new crop cultivars for adaptation to stress-related phenomena due to soil chemical toxicity and deficiency is a complex process. Data from nutrient culture trials, in which seedling plants are stressed with a deficiency or excess of mineral elements, do not correlate well with those from similar field stress conditions using the same germplasm. Further, evaluating segregating populations in nutrient culture can result in little or no genetic gain due to selection. Field screening efforts are plagued with genotype x environmental interactions caused by a multitude of biotic and abiotic factors. Selecting the proper level of stress for field evaluations and maintaining this level in a dynamically changeable medium like soil can be difficult. Genetic improvement of sorghum under field conditions similar to those encountered by farmers, however, has nearly always been obtained.; 1997

Variabilidade e progresso genético com seleção recorrente em arroz de terras altas; Variability and genetic progress with recurrent selection in upland rice

Morais Júnior, Odilon Peixoto de
Fonte: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Genética e Melhoramento de Plantas; Escola de Agronomia e Engenharia de Alimentos - EAEA (RG) Publicador: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Genética e Melhoramento de Plantas; Escola de Agronomia e Engenharia de Alimentos - EAEA (RG)
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
56.13%
Rice (Oryza sativa L.) is the most important cereal in the world as a major component of the staple food of the world’s population. The increase of the yield potential of new upland rice cultivars has been became highlighted as a main challenge for the plant breeding in this millennium. The increasing mean yield of cultivars becomes more difficult to identify superior genotypes, because the contrasts among elite-lines are becoming smaller. This highlights the importance of developing improved populations with high frequency of favorable alleles and genetic variability. The recurrent selection is a method based on population breeding and the main characteristic is obtaining long-term results. Using the recurrent selection population CNA6 of upland rice, the objectives of this study were: (i) to obtain estimates of genetic and phenotypic parameters among S0:2 progenies for grain yield (PG, in kg ha-1) and plant height (AP, in cm), in four selection cycles; (ii) to determine the influence of the progeny x location interaction on estimates of genetic and phenotypic parameters; (iii) to estimate the genetic progress of the population along the four cycles of recurrent selection for PG, AP and days-to-flowering (DF, in days); and (iv) to evaluate the genetic potential of this population through the expected proportion of superior lines after each selection cycle. It was used the data set from yield trials of S0:2 progenies in the years 2000/01...

Genetic parameters and trends of morphometric traits of GIFT tilapia under selection for weight gain

Reis Neto, Rafael Vilhena; Oliveira, Carlos Antônio Lopes de; Ribeiro, Ricardo Pereira; Freitas, Rilke Tadeu Fonseca de; Allaman, Ivan Bezerra; Oliveira, Sheila Nogueira de
Fonte: Univ Sao Paolo Publicador: Univ Sao Paolo
Tipo: Artigo de Revista Científica Formato: 259-265
ENG
Relevância na Pesquisa
56.18%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); The main factor considered in breeding programs for fish is growth, which can be assessed in terms of a gain in either weight or body measurements. This study was undertaken to evaluate the morphometric traits of GIFT strain tilapia (Oreochromis sp.) selected for weight gain. The data set used contained information on 6,650 animals. The genetic values of 8,590 animals in a relationship matrix of five generations were predicted. The following morphometric measurements were evaluated: standard length; body depth and body width. Body area and volume were also calculated. Bi-character analyses involving morphometric traits were used to estimate (co)variance components. Heritability, larval and fingerling common environmental effects were estimated for each trait, together with the genetic and phenotypic correlations between traits. Bayesian procedures were utilised by Gibbs chains, and the convergence of the chains was tested using the Heidelberger and Welch method. Genetic trends were estimated by segmented regression of the fish breeding values of the generations considered in this study. Estimates of heritability (0.28 a 0.31) had moderate to high magnitudes for all traits. Genetic correlations between traits were all above 0.8...

Genetic improvement of peanut in Argentina between 1948 and 2004: Seed yield and its components

Haro, Ricardo J.; Baldessari, J.; Otegui, Maria Elena
Fonte: Elsevier Science Bv Publicador: Elsevier Science Bv
Tipo: info:eu-repo/semantics/article; info:ar-repo/semantics/artículo; info:eu-repo/semantics/publishedVersion Formato: application/pdf
ENG
Relevância na Pesquisa
56.2%
In Argentina, peanut (Arachis hypogaea L.) breeding has been based on seed yield per se plus defensive and seed quality traits. An important milestone was the shift from cultivars with erect growth habit (CEGH) to cultivars with procumbent (CPGH) growth habit that took place in the 1970s. However, there is no information on the genetic gain obtained for seed yield and related secondary traits (numerical and physiological determinants of seed yield), or on the effect of growth habit shift on these traits. Field experiments were performed to compute this gain and the relationships between traits in potential growing conditions. Eight cultivars released between 1948 and 2004 were evaluated. Introduction of the procumbent habit in 1975 produced a mean increase of 52% in seed yield, which was related to year of cultivar release (YOR) only for CPGH (mean genetic gain of 0.43% y−1). This trend was driven by seed weight, a trait that registered a mean genetic gain of 0.29% y−1 (P = 0.026) only among procumbent cultivars (56% increase with habit change between 1973 and 1975). No genetic gain was computed for seed numbers, and only a 10% difference was registered between growth habits (CPGH > CEGH). Seed number was related to crop growth rate between R3 and R6.5 (r2 = 0.55...

Estimativa do progresso genético em soja no sul do Brasil a partir de resultados de experimentos de rendimento; Estimation of soybean genetic progress in the South of Brazil using multi-environmental yield trials

Lange, Cláudia Erna; Federizzi, Luiz Carlos
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/06/2009 ENG
Relevância na Pesquisa
56.03%
O sucesso de um programa de melhoramento durante um determinado período pode ser avaliado pelo ganho genético alcançado. Progresso genético pode ser estimado a partir de dados resultantes dos ensaios de avaliação de genótipos realizados rotineiramente em vários locais pelos programas de melhoramento de espécies anuais para fins de lançamento de novas cultivares comerciais. Os resultados de rendimento de grãos de 20 anos de experimentos de avaliação de linhagens derivadas de quatro programas de melhoramento de soja foram usados para estimar e comparar os ganhos genéticos obtidos em três grupos de maturação (precoce, médio e tardio) e em quatro regiões de cultivo do Estado do Rio Grande do Sul (Brasil). Os ganhos estimados variaram de zero a 71,5 kg ha-1 ano-1 (3,49% ao ano), dependendo do grupo de maturação e da região. Não foi detectado avanço genético para o grupo precoce em nenhuma das quatro regiões. Os ganhos obtidos nas regiões I e IV foram maiores que os das regiões II e III. Os esforços dos programas de melhoramento genético não refletiram de forma equivalente entre os grupos de maturação e não beneficiaram igualmente as regiões produtoras, indicando que os objetivos do melhoramento de soja no Estado devem ser reavaliados. Os ganhos estimados neste trabalho podem ser diferentes dos vivenciados pelos produtores rurais...

Contribuições genéticas e ambientais para aumento do rendimento do trigo em Minas Gerais, Brasil; Genetic and environmental contributions to increased wheat yield in Minas Gerais, Brazil

Cargnin, Adeliano; Souza, Moacil Alves de; Fronza, Vanoli; Fogaça, Cláudia Martellet
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/06/2009 ENG
Relevância na Pesquisa
56.09%
Devido à necessidade dos produtores por cultivares de trigo adaptados às condições climáticas do final da época das chuvas, desde 1976 a EPAMIG (Empresa de Pesquisa Agropecuária de Minas Gerais) vem desenvolvendo um programa de melhoramento genético. As estimativas dos progressos genéticos alcançados pelos programas de melhoramento são instrumentos hábeis para se quantificar a eficiência dos trabalhos executados. Quantificou-se o progresso genético obtido pelos programas de melhoramento do trigo de sequeiro no cerrado brasileiro no período de 1976 a 2005 utilizando-se resultados de produtividade de grãos obtidos nos ensaios de valor de cultivo e uso. O progresso genético médio anual estimado no período de 1976 a 2005 foi de 37 kg ha-1 ano-1 na produtividade média de grãos. O ganho genético, em produtividade, obtido no período estudado, indica que os programas de melhoramento de trigo de sequeiro no cerrado brasileiro são eficientes. Apesar de o ganho genético ter contribuído expressivamente, as melhorias ambientais e tecnológicas foram importantes para o acréscimo na produtividade, representando 47,4% do progresso total obtido. Os programas de melhoramento de trigo de sequeiro promovem 35% de renovação de genótipos ao longo dos anos.; Producers need wheat cultivars adapted to the predominant climate conditions of the end of the rainy period. Having this in mind...

Variação genética e ganhos obtidos por meio do melhoramento genético da seringueira; Genetic variation and realized genetic gain from rubber tree improvement

Gonçalves, Paulo de Souza; Aguiar, Adriano Tosoni da Eira; Costa, Reginaldo Brito da; Gonçalves, Elaine Cristine Piffer; Scaloppi Júnior, Erivaldo José; Branco, Roberto Botelho Ferraz
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/02/2009 ENG
Relevância na Pesquisa
55.98%
Partindo-se da polinização à recomendação de clones para o plantio, o ciclo de melhoramento da seringueira, o qual compreende três ciclos de seleção leva em torno de 20-30 anos. Cinco hectares de uma população clonal de seringueira [Hevea brasiliensis Willd. ex Adr. de Juss.) Muell.-Arg.] foram instalados em Votuporanga, região Noroeste do Estado de São Paulo. A população inclui 98 clones, cuja maioria é derivada de árvores selecionadas na floresta nativa de seringueira na Amazônia. Três testes de progênies de polinização aberta foram conduzidos nas estações experimentais de Pindorama, Jaú e Votuporanga. Mudas de 98 progênies inclusive a testemunha (CC) foram plantadas em cada um dos três locais. Foram feitas avaliações quando as plantas apresentaram um, dois e três anos respectivamente. A variação entre progênies para crescimento de perímetro do caule foi altamente significantes em todos os locais testados. Nas análises de variâncias conjuntas com os três locais também foram observadas diferenças entre progênies, e que o efeito da interação progênie × local não foi significativo. Estimativas de herdabilidade no sentido restrito em nível de árvore individual (h i²) foram variáveis dependentes das características...

Análise genética para resistência à fumagina e produção de palmito em Archontophoenix; Genetic analysis for sooty mold resistance and heart of palm yield in Archontophoenix

Bovi, Marilene Leão Alves; Resende, Marcos Deon Vilela de; Sáes, Luís Alberto; Uzzo, Roberta Pierry
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/04/2004 ENG
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Palmeiras do gênero Archontophoenix, utilizadas tanto como ornamentais quanto produtoras de palmito de qualidade, são susceptíveis à fumagina, doença associada à infestação por pulgões, que afeta a fotossíntese, o crescimento e a aparência das plantas. Foram avaliados a campo a resistência à fumagina conjuntamente com três caracteres associados ao crescimento em 24 famílias de meios-irmãos, 28 meses após o plantio, a fim de identificar a variabilidade genética para os caracteres resistência à fumagina, altura, diâmetro e número de folhas; estimar as correlações genotípicas e fenotípicas envolvendo esses quatro caracteres; e aplicar a estratégia de seleção usando o índice multiefeitos. Houve diferenças entre as famílias para os caracteres avaliados, sugerindo a possibilidade de seleção. O baixo coeficiente de variação observado para resistência à fumagina (9,48%) indica que o método de avaliação adotado, baseado em escala de notas após observação visual, foi eficiente e prático para comparar níveis de infestação do complexo fungo+pulgão em palmeiras do gênero Archontophoenix. As estimativas da herdabilidade no sentido restrito foram baixas a médias para os caracteres relacionados ao crescimento (0...