93 research outputs found
Definition of morphofunctional groups in Panicum maximum accessions by canonical variables analysis
Todos os textos, informa??es e resultados apresentados s?o de inteira responsabilidade dos autores.A avalia??o das caracter?sticas morfog?nicas em acesso de Panicum maximum apesenta grande potencial
para permitir a identifica??o precoce de grupos de plantas com caracter?sticas morfofuncionais afins. O objetivo
com o trabalho foi avaliar as caracter?sticas morfog?nicas de acessos de Panicum maximum e definir grupos
morfog?nicos a fins por meio da an?lise de vari?veis can?nicas. Foram avaliados 17 acessos em delineamento
em blocos ao acaso com tr?s repeti??es. Ap?s avalia??o da dispers?o dos escores relativos ?s vari?veis
can?nicas, verificou-se a forma??o de sete grupos morfofuncionais. Maior destaque foi dado ?s plantas dos
grupos 5, 6 e 7. O grupo 7 apresentou maior taxa de alongamento foliar, longa dura??o de vida da folha e o
maior comprimento final da l?mina. No grupo 5, registrou-se alta taxa de alongamento e de aparecimento foliar
associadas a baixa senesc?ncia. O grupo 6 reuniu maior alongamento de folhas a menor longevidade, indicando
necessidade de manejo mais intensivo. Foi poss?vel formar grupos morfofuncionais com base nas caracter?sticas
morfog?nicas de acessos de Panicum maximum. Destaca-se a identifica??o das plantas dos grupos 5 e 7 como
plantas com grande potencial para produ??o de folhas e longa janela de corte, e das plantas do grupo 6 como
plantas que demandar?o manejo mais frequente.ABSTRACT
The evaluation of morphogenetic characteristics in Panicum maximum accessions has potential in the
previous identification of groups of plants with related morphofunctional characteristics. The study was carried
out to evaluate the morphogenetic characteristics of Panicum maximum accessions and to define related
morphogenetic groups by analysis of canonical variables. Were evaluated 17 accessions in a complete
randomized block design with three replicate. After the evaluation of the scores related to canonical variables, it
verified the formation of seven morphofunctional groups. We emphasize the groups 5, 6 and 7. The group 7 had
higher leaf elongation rate, leaf life spam and leaf length. In the group 5, was observed high leaf elongation and
appearance rate associated with low senescence. The group six had high elongation and low leaf life spam,
indicating these plants to a more intensive management. With the canonical variable analysis was possible the
identification of morphofunctional groups based on the morphogenetic characteristics of Panicum maximum
accessions. The identification of the groups 5 and 7 as high production plants and with a longer harvest period
and the groups 6 with plants that needs more frequent defoliation
Genetic parameters of morphogenetic traits in Panicum maximum acessions
Todos os textos, informa??es e resultados apresentados s?o de inteira responsabilidade dos autores.Objetivou-se com este trabalho estimar par?metros gen?ticos de caracter?sticas morfog?nicas em acessos de
Panicum maximum. Foram avaliados 17 acessos (previamente selecionados pela Embrapa Gado de Corte) em
delineamento em blocos ao acaso com tr?s repeti??es. Os acessos foram avaliados por meio de cortes a 25 cm do
n?vel do solo em parcelas de 4,0 m2, com espa?amento de 1 m entre linhas. A partir das an?lises dos resultados,
foi poss?vel notar que apenas as caracter?sticas taxa de alongamento de colmo, taxa de alongamento de folha e
comprimento final da lamina foram estatisticamente diferentes entre os acessos avaliados. Para taxa de
alongamento de colmo o coeficiente de varia??o do ambiente apresentou valor elevado. O coeficiente de
varia??o genot?pico da taxa de alongamento de colmo foi o maior entre as vari?veis avaliadas, indicando o
potencial de ganho na sele??o para o mesmo. Para o comprimento final da l?mina, foram observados coeficiente
da varia??o do ambiente e coeficiente da varia??o genot?pica inferiores ? taxa de alongamento do colmo,
contudo, foram obtidos herdabilidade e raz?o CVg/CVe semelhantes. Os coeficientes de varia??o residual e
genot?pico da taxa de alongamento foliar foram intermedi?rios em rela??o ?s demais caracter?sticas e assumiram
valores pr?ximos, que permitiram a estimativa de uma raz?o CVg/CVe pr?xima da unidade. O alongamento de
folhas apresenta maior potencial para ser inserido no processo de avalia??o e sele??o de forrageiras devido a sua
alta herdabilidade e raz?o entre os coeficientes de varia??o genot?pico e residual.The experiment was carried out to estimate the genetic parameters of morphogenetic characteristics in Panicum
maximum accessions. Were evaluated 17 accessions in a complete block design with three replicate. The
accessions were evaluated by cutting at 25 cm from de level soil in plots of 4 m?, with 1 m intercrop. It was
possible to note only the stems elongation rate, leaf elongation rate and leaf length were statistically different
between the accessions. To stems elongation rate we had high environmental coefficient of variation. In spite of
this the genotypic coefficient of variation was also the higher between the characteristics evaluated, indicating
potential to reduce this by selection. To leaf length, were observed genotypic and environmental coefficient of
variation lower than the stems elongation rate, however were observed similar heritability and
genotypic/environmental coefficient of variation rate. The genotypic and environmental coefficient of variation
of leaf elongation rate were intermediated between the other characteristics and had next values, so the
genotypic/environmental coefficient of variation rate was the higher in the experiment and next from one (0,93).
The leaf elongation rate has potential to be included in the process of evaluation and selection of forage plants
duly its high heritability and favorable environmental/genotypic coefficient of variation rate
Identification of stable reference genes for quantitative PCR in koalas
To better understand host and immune response to diseases, gene expression studies require identification of reference genes with stable expression for accurate normalisation. This study describes the identification and testing of reference genes with stable expression profiles in koala lymph node tissues across two genetically distinct koala populations. From the 25 most stable genes identified in transcriptome analysis, 11 genes were selected for verification using reverse transcription quantitative PCR, in addition to the commonly used ACTB and GAPDH genes. The expression data were analysed using stable genes statistical software - geNorm, BestKeeper, NormFinder, the comparative ΔCt method and RefFinder. All 13 genes showed relative stability in expression in koala lymph node tissues, however Tmem97 and Hmg20a were identified as the most stable genes across the two koala populations
Milk production systems retated momba?a grass
Todos os textos, informa??es e resultados apresentados s?o de inteira responsabilidade dos autores.A produ??o animal em pastagens apresenta vantagens em rela??o aos outros sistemas de produ??o. Geralmente,
o pasto ? o alimento mais vi?vel economicamente para a alimenta??o de ruminantes. O capim-momba?a ? uma
cultivar de Panicum maximum nativa da ?frica, essa cultivar apresenta desenvolvimento satisfat?rio em sistemas
de manejo mais intensivos e com altas taxas de lota??o. Por?m, para garantir a produtividade animal, a fisiologia
da forrageira deve ser respeitada com auxilio das alturas de entrada de sa?da adequadas a cada esp?cie.Livestock production in pastures has advantages over other production systems. Generally, the grass is the most
economically viable food for feeding to ruminants. The momba?a is a cultivar of Panicum maximum native to
Africa, this cultivar has developed satisfactorily in more intensive management systems and high stocking rates.
However, to ensure animal productivity, forage physiology must be respected with the aid of input output
heights appropriate to each species
Population ecology of the sea lamprey (Petromyzon marinus) as an invasive species in the Laurentian Great Lakes and an imperiled species in Europe
The sea lamprey Petromyzon marinus (Linnaeus) is both an invasive non-native species in the Laurentian Great Lakes of North America and an imperiled species in much of its native range in North America and Europe. To compare and contrast how understanding of population ecology is useful for control programs in the Great Lakes and restoration programs in Europe, we review current understanding of the population ecology of the sea lamprey in its native and introduced range. Some attributes of sea lamprey population ecology are particularly useful for both control programs in the Great Lakes and restoration programs in the native range. First, traps within fish ladders are beneficial for removing sea lampreys in Great Lakes streams and passing sea lampreys in the native range. Second, attractants and repellants are suitable for luring sea lampreys into traps for control in the Great Lakes and guiding sea lamprey passage for conservation in the native range. Third, assessment methods used for targeting sea lamprey control in the Great Lakes are useful for targeting habitat protection in the native range. Last, assessment methods used to quantify numbers of all life stages of sea lampreys would be appropriate for measuring success of control in the Great Lakes and success of conservation in the native range
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