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Provedor de dados:  Scientia Agricola
País:  Brazil
Título:  Tiller size/population density compensation in grazed Coastcross bermudagrass swards
Autores:  Sbrissia,André Fischer
Silva,Sila Carneiro da
Carvalho,Carlos Augusto Brandão de
Carnevalli,Roberta Aparecida
Pinto,Luiz Felipe de Moura
Fagundes,Jaílson Lara
Pedreira,Carlos Guilherme Silveira
Data:  2001-12-01
Ano:  2001
Palavras-chave:  Cynodon
LAI
Tiller
Morphology
Resumo:  Several compensatory mechanisms in pastures do not allow optimisation of responses from the processes of herbage production and utilisation. Compensation due to tiller size/density relationships is one of these mechanisms. This experiment evaluated this process for Coastcross bermudagrass and compared the responses to those reported for temperate forages. Treatments were "steady state" sward surface heights of 5, 10, 15, and 20 cm that were maintained from August, 1998, through July, 1999 by sheep grazing. The experimental design was a randomised complete block, replicated four times. Pasture responses were evaluated on four separate dates (15/12/1998, 25/01/1999, 07/04/1999 and 04/07/1999) with respect to: tiller population density, tiller weight, leaf mass and leaf area per tiller and herbage mass (biomass). Tiller volume, leaf area index (LAI), tiller leaf:stem ratio and tiller leaf area:volume ratio (R) were calculated. Simple regression analyses between tiller population density and tiller weight were also performed. Coastcross swards showed a tiller size/density compensation mechanism where high tiller population densities were associated with small tillers and vice-versa; except on the last evaluation. However, regression analysis revealed linear coefficients of -3.83 to -2.05, which are lower than the theoretical expectation of -3/2. The lower R values observed, when compared to those reported for perennial ryegrass, suggest that Coastcross swards optimised their LAI via clonal integration among tillers in contrast with tillers of cool-season grasses that respond more as individuals. However, this hypothesis has yet to be experimentally verified.
Tipo:  Info:eu-repo/semantics/article
Idioma:  Inglês
Identificador:  http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162001000400002
Editor:  São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Relação:  10.1590/S0103-90162001000400002
Formato:  text/html
Fonte:  Scientia Agricola v.58 n.4 2001
Direitos:  info:eu-repo/semantics/openAccess
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