Flávia Maria Avelar Gonçalves

Correlação entre crescimento e produtividade de cultivares de café em diferentes regiões de Minas Gerais, Brasil

The objective of this work was to evaluate coffee growth traits in the initial stages of development and to determine its correlation with the crop initial yield in different environments. Twenty-two cultivars resistant to rust and three susceptible ones were evaluated in five representative coffee growing localities in the state of Minas Gerais, Brazil. The experiment was carried out from 2005 to 2008 in a randomized complete block design with three replicates. Besides initial yield, five growth traits were evaluated 12 months after planting: stem diameter, number and length of plagiotropic branches, plant height, and number of nodes. The genotypic and phenotypic correlations were evaluated for all traits. Pau Brasil MG1 and Catuai Amarelo IAC 62 cultivars show superiority in at least four out of the five evaluated characters, in all growing localities. There is a positive correlation between initial yield and the evaluated growth traits, except number of nodes.

Índices de seleção no aprimoramento simultâneo dos componentes da produção de frutos em açaizeiro

The objective of this work was to determine the most appropriate strategy to simultaneously increase fruit production components of assai palm (Euterpe oleracea). An experiment with 25 half-sib progenies was carried out in the county of Santa Isabel, PA, Brazil, using a randomized complete block design with four replicates and five plants per plot. The Smith & Hazel, Williams, and Mulamba & Mocks selection indexes were applied in three selective strategies. The coefficients of genetic variation, heritability, the ratio between the genetic correlation of the trait under selection and fruit yield, and the sum of all genetic correlations between the traits that comprise the index and fruit yield were used as economic weights. Weighting of the correlation ratio allowed the selection indexes to discriminate the best progenies in the different selection strategies evaluated. Simultaneous selection by the Mulamba & Mock index, as to the number of fruiting months, number of bunches harvested, fruit yield, and number of rachilles per bunch, robustly estimates genetic gains.

Importância das interações cultivares x locais e cultivares x anos na avaliação de milho na safrinha

Com o objetivo de verificar a importância da interacao cultivares x locais e cultivares x anos e de identificar entre os hibridos ja disponiveis os que sejam mais adaptados e estaveis para o cultivo em safrinha, foram estimados os parâmetros de adaptabilidade e estabilidade a partir de dados obtidos em experimentos de avaliacao de cultivares de milho na safrinha, nos anos de 1993, 1994 e 1995. Esses experimentos foram conduzidos nos Estados de Sao Paulo, Goias e Parana. O delineamento utilizado foi em blocos casualizados com tres repeticoes. Constatou-se que a magnitude da variância da interacao cultivares com anos dentro de locais foi mais expressiva do que entre locais, o que indica a necessidade de que as avaliacoes de cultivares na safrinha sejam realizadas num maior numero de anos. As cultivares diferiram quanto a adaptabilidade e estabilidade de producao de graos. Os materiais que se destacaram como mais adaptados e estaveis foram o hibrido simples Zeneca 8452, o hibrido triplo C 805 e o hibrido duplo Agromen 2012. Ja os hibridos duplos BR 201, Planagri 411, AG 303 e C 125 foram os que mostraram menor adaptacao e maior instabilidade.

Correlações genéticas e análise de trilha para componentes da produção de frutos de açaizeiro

O conhecimento das correlacoes geneticas entre os principais caracteres utilizados no melhoramento de plantas serve de base para delinear estrategias otimizadas de selecao. O procedimento da analise de trilha permite refinar essas correlacoes, desdobrando-as em efeitos diretos e indiretos sobre o carater principal. O objetivo deste trabalho foi desdobrar as correlacoes geneticas de caracteres relativos ao cacho e a producao de frutos em progenies de meios-irmaos de acaizeiro em efeitos diretos e indiretos sobre a producao total de frutos, a fim de verificar a melhor estrategia de selecao para obtencao de progenies mais produtivas. Foi instalado um experimento com 25 progenies de meios-irmaos em blocos ao acaso, com quatro repeticoes e parcela de cinco plantas. Os dados dos anos agricolas de 2005, 2006 e 2007 foram analisados pelo enfoque de modelos mistos, e as correlacoes geneticas, submetidas a analise de trilha. A producao de frutos correlacionou-se ao numero de meses em producao, numero total de cacho, peso de frutos por cacho e ao numero de raquilas por cacho. No entanto, pela analise de trilha, apenas o peso de frutos por cacho, o numero de cachos e o numero de raquilas por cacho mostram-se como os principais determinantes na variacao da producao de frutos de acaizeiro. Dentre esses caracteres, o numero de raquilas por cacho e o menos influenciado pelo ambiente e, portanto, mais promissor para obter ganhos indiretos na producao total de frutos.

Eficiência na seleção de progênies de cafeeiro avaliadas em Minas Gerais

The present work had the aim of verifying the selection efficiency of coffee plants originated from the crossing between Catuai and Icatu with Timor Hybrid. Eighteen progenies developed by the Program of Genetic Improvement of Epamig/UFLA/ UFV were evaluated. Coffee plants were planted in December 2005 in the following counties: Lavras, Campos Altos and Patrocinio, in the State of Minas Gerais. The characteristics analyzed were: productivity, grain size and proportion of cherry fruit. In order to verify the efficiency of the selection, the index of coincidence was applied according to the methodology of Hamblin and Zimmermann (1986), as well as the magnitude of the interaction progenies x environments and its decomposi - tion in simple and complex parts using the methodology of Cruz and Castoldi ( 1991). The predominance of the complex part in relation to the simple one in the interaction of the progenies x environments confirms the low or absence coincidence of the progenies in different environments, raising difficulties for a general recommendation for different coffee regions in the State of Minas Gerais.

Avaliação do teor de cafeína em folhas e grãos de acessos de café arábica

The aim of this study was to identify, within the germplasm bank of the Minas Gerais state, Coffea arabica L. accessions with low levels of caffeine and check the correlation between grain and leaves in seedling stage, making possible the practice of early selection. Seventy-five coffe accessions (cultivars, hybrids and several wild genotypes) were evaluated from the coffee germplasm bank of the Minas Gerais state. In the correlation study, eight cultivars were used on randomized complete block design with three replications. Were evaluated the caffeine levels in the grains and the third and fourth pair of true leaves. Six accessions had caffeine levels in grains smaller than 0.88%. Was also detected a significant correlation between the caffeine levels in the third (0.69) and fourth (0.92) pair of leaves and grains. Genotypes were identified with low levels of caffeine and great yield may be used as parental in breeding programs. It is possible to perform early selection for caffeine content in coffee plants, still in the seedling stage, by evaluating the fourth pair of leaves.

Seleção de progênies de eucalipto pelo índice Z por MQM e Blup

Abstract – The objective of this work was to evaluate the efficiencyof the Z index (sum of standardized variables index), in the selection of full‑sib progenies between Eucalyptus grandis and Eucalyptus urophylla via least square method (LSM) and best linear unbiased prediction (Blup) procedures. The experiments were carried out in two soil types and environments, in a randomized complete block design, with fivereplicates, eight plants per plot and 3x2 m spacing. Wood average annual increment, basic density, screened pulp yield, and effective alkali were evaluated for three‑year‑old plants. The Z index was obtained for each plant in order to compare the efficiencyof selection for the best progenies by LSM and Blup procedures. Subsequently, the predicted averages to Z index were obtained and ranked. For comparison, the classic index was used. The coincidence among the best progenies selected by classical and Z index was good. However, the Z index allows a graphic display that enables to check in which characters the progenie has a disability. There is no difference between the best progenies selected by the Z index via LSM and Blup.Index terms:

ESTRATÉGIAS NA SELEÇÃO SIMULTÂNEA DE VÁRIOS CARACTERES NO MELHORAMENTO DO Eucalyptus

The aim of this study was i) to compare the results obtained with the Z index (sum of standardized variables) in relation to the classical (Smith, 1936; HAZEL, 1943) and rank sum indexes (Mulamba and MOCK, 1978) by means of the growth and wood technology traits and ii) to verify the progeny x environment interaction in simultaneous multiple trait selection, based on the Z index. Thus, we used a full sib progeny test of Eucalyptus urophylla and Eucalyptus grandis evaluated in two locations in the municipality of Ipaba, Minas Gerais state. At three years of age, the following traits were evaluated: average yearly increase of wood, wood density, refined pulp yield and effective alkali. There was good agreement in the progeny selection by the indexes. Thus, use of the Z index of standardized variables is a good option in simultaneous selection of multiple traits in the forestry sector through its ease of application and, above all, interpretation of results. The mentioned index revealed efficient in the study of the genotypes x environments interaction.

Tamanho de parcela e efeito de bordadura no melhoramento de Urochloa ruziziensis

The objective of this work was to assess the need for a border area and to estimate the optimum plot size in experiments for the evaluation of Urochloa ruziziensis. Plant height and green mass production of eight half-sib progenies of U. ruziziensis were evaluated in two cuttings. A randomized complete block design was used, with four replicates and 16 m2 plots. Each plot was subdivided into 32 strata of 0.5 m2, with each stratum being considered as a basic unit. To determine the need for a border area, analysis of variance was carried out considering the position of the basic unit in the plot. Estimates of optimum plot size were made by the maximum curvature of the coefficient of variation method and by the resampling method. The use of borders does not affect the mean performance and classification of the half-sib progenies evaluated. The use of 3 m2 plots is enough to obtain good experimental accuracy in an experiment with half-sib progenies of U. ruziziensis.

Genomic selection prediction models comparing sequence capture and SNP array genotyping methods

The successful application of genomic selection (GS) approaches is dependent on genetic makers derived from high-throughput and low-cost genotyping methods. Recent GS studies in trees have predominantly relied on SNP arrays as the source of genotyping, though this technology has a high entry cost. The recent development of alternative genotyping platforms, tailored to specific species and with low entry cost, has become possible due to advances in next-generation sequencing and genome complexity reduction methods such as sequence capture. However, the performance of these new platforms in GS models has not yet been evaluated, or compared to models developed from SNP arrays. Here, we evaluate the impact of these genotyping technologies on the development of GS prediction models for a Eucalyptus breeding population composed of 739 trees phenotyped for 13 wood quality and growth traits. Genotyping data obtained with both methods were compared for linkage disequilibrium, minor allele frequency, and missing data. Phenotypic prediction methods RR-BLUP and BayesB were employed, while predictive ability using cross validation was used to evaluate the performance of GS models derived from the different genotyping platforms. Differences in linkage disequilibrium patterns, minor allele frequency, missing data, and marker distribution were detected between sequence capture and SNP arrays. However, RR-BLUP and BayesB GS models resulted in similar predictive abilities. These results demonstrate that both genotyping methods are equivalent for genomic prediction of the traits evaluated. Sequence capture offers an alternative for species where SNP arrays are not available, or for when the initial development cost is too high.