Avaliação de cruzamentos dialélicos para produção de grãos e caracteres agronômicos, e perspectivas de melhoramento em soja.

O objetivo deste trabalho foi estimar os parâmetros da capacidade geral e específica de combinação, identificando genitores e combinações promissoras para gerar populações segregantes que atendam a um programa de melhoramento genético de soja no Estado de São Paulo

Yield and fruit quality of Santa Cruz and Italian tomatoes depending on fruit thinning

O manejo do tomateiro cultivado em ambiente protegido, com ênfase no raleio de frutos, pode contribuir de forma significativa para a produção de frutos de qualidade superior, expressando assim o potencial de cada cultivar. Foi avaliado o efeito do raleio de frutos na produtividade e seus componentes e em alguns atributos de qualidade de frutos de genótipos de tomateiro dos segmentos Santa Cruz e Italiano de crescimento indeterminado, visando ao consumo in natura. Avaliaram-se 12 genótipos de tomate de mesa (seis híbridos experimentais e seis cultivares) e dois modos de condução (plantas conduzidas com e sem raleio de frutos). O experimento foi com parcelas subdivididas, distribuídas em blocos completos ao acaso com três repetições. As parcelas foram representadas pelos genótipos e as subparcelas pelos modos de condução. Avaliaram-se o número de frutos por planta, produtividade comercial de frutos, produtividade de frutos não-comercializáveis, massa média do fruto, comprimento e largura do fruto, pH, teor de sólidos solúveis totais (SS), acidez titulável (AT), relação entre SS e AT, teor de ácido ascórbico e teor de licopeno. O raleio dos frutos proporcionou incremento da produtividade comercial, massa média, comprimento e largura do fruto para os híbridos THX-02 e THX-03, do segmento Santa Cruz, e THX-04, THX-05 e Netuno, do segmento Italiano e não mostrou vantagens para a produção e seus componentes para os demais genótipos e características avaliadas. Considerando o raleio de frutos, os genótipos Giuliana e Sahel obtiveram maior produtividade comercial e massa média do fruto. Sem o raleio de frutos, 'Netuno' alcançou maior número de frutos por planta, porém, o híbrido Sahel foi quem se destacou por apresentar maior produtividade comercial e massa média do fruto. O raleio não influenciou a qualidade organoléptica dos genótipos avaliados. 'Avalon' apresentou maior teor de ácido ascórbico que 'Netuno' e 'Sahel'. 'Débora Max', THX-01, THX-02 e THX-04 foram semelhantes entre si quanto ao teor de licopeno e superaram 'Giuliana', 'Sahel', THX-03 e THX-06.The management of the tomato plant under greenhouse, with emphasis on fruit thinning, contributes significantly to the production of fruits of superior quality, expressing the potential of each cultivar. We determined the effect of fruit thinning on yield and its components in tomato hybrids of the Santa Cruz and Italian types of indeterminate growth, and we performed the qualitative characterization of the fruits, aiming in natura market. Twelve fresh-market tomato genotypes (six experimental hybrids and six commercial cultivars) and two training methods (with and without manual fruit thinning) were evaluated. A randomized complete block design was used in this trial, with split-plots and three replications. The plots were represented by genotypes and the subplots were constitued by training methods. Number of fruits per plant, yield of marketable and not marketable fruits, average fruit weight, fruit length and fruit width were measured. For quantitative characterization, pH, soluble solids concentration (SS), tritratable acidity (AT), ascorbic acid content, SS and AT ratio and lycopene content were measured. The fruit thinning increased marketable yield, average weight, length and width for the Santa Cruz hybrids THX-02 and THX-03 and for THX-04, THX-05 and Netuno, classified as Italian type. The fruit thinning did not provide benefits for yield and its components for the other evaluated characteristics and genotypes. Giuliana and Sahel genotypes presented higher marketable yield and average fruit weight. Without fruit thinning, 'Netuno' reached the highest number of fruits per plant, but the hybrid Sahel showed higher marketable yield and average fruit weight. Thinning did not affect the organoleptic quality of the genotypes. 'Avalon' showed higher ascorbic acid content than 'Netuno' and 'Sahel', and 'Débora Max', 'THX-01', 'THX-02' and 'THX-04', which were similar to each other in the content of lycopene, overcame 'Giuliana', 'Sahel', 'THX-03', and 'THX-06'.FAPESPCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

Avaliação de genitores de soja adaptados ao Estado de São Paulo em cruzamentos dialélicos.

O objetivo deste trabalho foi estimar os parâmetros da capacidade geral e específica de combinação entre seis cultivares de soja adaptadas às condições de cultivo do Estado de São Paulo, identificando genitores e combinações promissoras. Os seis genitores e os 15 cruzamentos foram avaliados em um experimento em blocos casualizados com 20 repetições, utilizando parcelas lineares de 2 m espaçadas de 0,5 m, contendo 30 plantas após o desbaste

Avaliação de duas populações de soja derivadas do cruzamneto de genitores com alta e baixa divergência genética.

O objetivo deste trabalho foi comparar o desempenho de duas populações de soja derivadas do cruzamento de genitores com baixa DG e alta DG, obtidas a partir de marcadores moleculares AFLP.Resumo

Eficiência de um retrocruzamento no melhoramento de caracteres quantitativos em soja.

Este trabalho foi conduzido para avaliar a eficiência de uma geração de retrocruzamento no desenvolvimento de linhas puras superiores de soja, em uma população derivada de um cruzamento biparental entre os cultivares BRS-134 e EMGOPA-315, em que este último foi utilizado como genitor recorrente, por ser mais produtivo.Resumo

Measurement of νˉμ\bar{\nu}_{\mu} and νμ\nu_{\mu} charged current inclusive cross sections and their ratio with the T2K off-axis near detector

We report a measurement of cross section $\sigma(\nu_{\mu}+{\rm nucleus}\rightarrow\mu^{-}+X)$ and the first measurements of the cross section $\sigma(\bar{\nu}_{\mu}+{\rm nucleus}\rightarrow\mu^{+}+X)$ and their ratio $R(\frac{\sigma(\bar \nu)}{\sigma(\nu)})$ at (anti-)neutrino energies below 1.5 GeV. We determine the single momentum bin cross section measurements, averaged over the T2K $\bar{\nu}/\nu$-flux, for the detector target material (mainly Carbon, Oxygen, Hydrogen and Copper) with phase space restricted laboratory frame kinematics of $\theta_{\mu}$500 MeV/c. The results are $\sigma(\bar{\nu})=\left( 0.900\pm0.029{\rm (stat.)}\pm0.088{\rm (syst.)}\right)\times10^{-39}$ and $\sigma(\nu)=\left( 2.41\ \pm0.022{\rm{(stat.)}}\pm0.231{\rm (syst.)}\ \right)\times10^{-39}$in units of cm$^{2}$/nucleon and$R\left(\frac{\sigma(\bar{\nu})}{\sigma(\nu)}\right)= 0.373\pm0.012{\rm (stat.)}\pm0.015{\rm (syst.)}$.Comment: 18 pages, 8 figure

No Origin, No Problem for Yeast DNA Replication

Eukaryotic DNA replication initiates from multiple sites on each chromosome called replication origins (origins). In the budding yeast Saccharomyces cerevisiae, origins are defined at discrete sites. Regular spacing and diverse firing characteristics of origins are thought to be required for efficient completion of replication, especially in the presence of replication stress. However, a S. cerevisiae chromosome III harboring multiple origin deletions has been reported to replicate relatively normally, and yet how an origin-deficient chromosome could accomplish successful replication remains unknown. To address this issue, we deleted seven well-characterized origins from chromosome VI, and found that these deletions do not cause gross growth defects even in the presence of replication inhibitors. We demonstrated that the origin deletions do cause a strong decrease in the binding of the origin recognition complex. Unexpectedly, replication profiling of this chromosome showed that DNA replication initiates from non-canonical loci around deleted origins in yeast. These results suggest that replication initiation can be unexpectedly flexible in this organism

Displacement and re-accumulation of centromeric cohesin during transient pre-anaphase centromere splitting

The ring-shaped cohesin complex links sister chromatids until their timely segregation during mitosis. Cohesin is enriched at centromeres where it provides the cohesive counterforce to bipolar tension produced by the mitotic spindle. As a consequence of spindle tension, centromeric sequences transiently split in pre-anaphase cells, in some organisms up to several micrometers. This ‘centromere breathing’ presents a paradox, how sister sequences separate where cohesin is most enriched. We now show that in the budding yeast Saccharomyces cerevisiae, cohesin binding diminishes over centromeric sequences that split during breathing. We see no evidence for cohesin translocation to surrounding sequences, suggesting that cohesin is removed from centromeres during breathing. Two pools of cohesin can be distinguished. Cohesin loaded before DNA replication, which has established sister chromatid cohesion, disappears during breathing. In contrast, cohesin loaded after DNA replication is partly retained. As sister centromeres re-associate after transient separation, cohesin is reloaded in a manner independent of the canonical cohesin loader Scc2/Scc4. Efficient centromere re-association requires the cohesion establishment factor Eco1, suggesting that re-establishment of sister chromatid cohesion contributes to the dynamic behaviour of centromeres in mitosis. These findings provide new insights into cohesin behaviour at centromeres

ATP-dependent chromatin remodeling shapes the DNA replication landscape.

The eukaryotic DNA replication machinery must traverse every nucleosome in the genome during S phase. As nucleosomes are generally inhibitory to DNA-dependent processes, chromatin structure must undergo extensive reorganization to facilitate DNA synthesis. However, the identity of chromatin-remodeling factors involved in replication and how they affect DNA synthesis is largely unknown. Here we show that two highly conserved ATP-dependent chromatin-remodeling complexes in Saccharomyces cerevisiae, Isw2 and Ino80, function in parallel to promote replication fork progression. As a result, Isw2 and Ino80 have especially important roles for replication of late-replicating regions during periods of replication stress. Both Isw2 and Ino80 complexes are enriched at sites of replication, suggesting that these complexes act directly to promote fork progression. These findings identify ATP-dependent chromatin-remodeling complexes that promote DNA replication and define a specific stage of replication that requires remodeling for normal function

Novel features of ARS selection in budding yeast Lachancea kluyveri

<p>Abstract</p> <p>Background</p> <p>The characterization of DNA replication origins in yeast has shed much light on the mechanisms of initiation of DNA replication. However, very little is known about the evolution of origins or the evolution of mechanisms through which origins are recognized by the initiation machinery. This lack of understanding is largely due to the vast evolutionary distances between model organisms in which origins have been examined.</p> <p>Results</p> <p>In this study we have isolated and characterized autonomously replicating sequences (ARSs) in <it>Lachancea kluyveri </it>- a pre-whole genome duplication (WGD) budding yeast. Through a combination of experimental work and rigorous computational analysis, we show that <it>L. kluyveri </it>ARSs require a sequence that is similar but much longer than the ARS Consensus Sequence well defined in <it>Saccharomyces cerevisiae</it>. Moreover, compared with <it>S. cerevisiae </it>and <it>K. lactis</it>, the replication licensing machinery in <it>L. kluyveri </it>seems more tolerant to variations in the ARS sequence composition. It is able to initiate replication from almost all <it>S. cerevisiae </it>ARSs tested and most <it>Kluyveromyces lactis </it>ARSs. In contrast, only about half of the <it>L. kluyveri </it>ARSs function in <it>S. cerevisiae </it>and less than 10% function in <it>K. lactis</it>.</p> <p>Conclusions</p> <p>Our findings demonstrate a replication initiation system with novel features and underscore the functional diversity within the budding yeasts. Furthermore, we have developed new approaches for analyzing biologically functional DNA sequences with ill-defined motifs.</p