Morphogenetic and structural comparative characterization of tropical forage grass cultivars under free growth

RESUMO -Foram avaliadas as características morfogênicas e estruturais de gramíneas forrageiras com o objetivo de agrupá-las, de acordo com seu padrão de desenvolvimento, em seus respectivos grupos funcionais. As gramíneas foram plantadas em parcelas de 1,0 m 2 com 24 plantas, em delineamento de blocos completos casualizados com três repetições. Os dados foram submetidos à análise de fatores, reduzindo as variáveis em quatro fatores: desenvolvimento de massa, mortalidade de perfilhos, estádio de desenvolvimento e longevidade foliar. Os dados foram submetidos à análise de agrupamento por otimização de Tocher adotando-se a distância euclidiana média como medida básica de dissimilaridade. As gramíneas foram agrupadas da seguinte forma: Verão -grupo I (Xaraés, Massai, Mombaça e Marandu); grupo II (Gordura e Aruana); e grupo III (Jaraguá). Outonogrupo I (Mombaça, Massai, Xaraés, Marandu e Gordura); grupo II -(Jaraguá); e grupo III (Aruana). Possivelmente a maior participação do fator mortalidade de perfilhos na formação dos grupos no período de outono influenciou na reorganização dos grupos. Os padrões de desenvolvimento de massa dos diferentes grupos de gramíneas diferiram entre si quanto à forma de utilização dos recursos disponíveis. Houve mudança nos escores de todos os fatores com a mudança do período do verão para o outono. O agrupamento funcional comprova que gramíneas de gêneros e/ou espécies diferentes podem ser enquadradas em um mesmo grupo.Palavras-chave: análise multivariada, avaliação de gramíneas, características estruturais, morfogênese Functional clusters of tropical forage grassesABSTRACT -Morphogenetic and structural characteristics of forage grasses were evaluated in order to group them according to their pattern of development in their respective functional groups. Grasses were planted in plots of 1.0 m 2 with 24 plants in a completely randomized block design with three replications. Data were submitted to factor analysis, reducing the variables to four factors: mass development, tiller mortality, developmental stage and leaf longevity. The data were submitted to cluster analysis by Tocher's optimization by adopting the mean Euclidean distance as a basic measure of dissimilarity. Grasses were grouped as follows: Summer -the group I (Xaraés, Massai, Mombaca and Marandu); group II (Molassa and Aruana); and group III (Jaraguagrass). Fall -group I (Mombaca, Massai, Xaraés, Marandu and Molassa); group II -(Jaraguagrass); and group III (Aruana). Possibly, the greater role of the tiller mortality factor in the formation of groups in the fall influenced the reorganization of the groups. The patterns of mass development of the different groups of grasses differ from each other as for the means of utilizing the resources available. There was a change in the scores of all factors with the change of the period from summer to Fall. The functional clustering of grasses demonstrates that gender and/or different species can be placed in the same group.

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“…Outra forma de inferir sobre o padrão de desenvolvimento das gramíneas é por intermédio da formação de grupos funcionais (Silveira et al, 2010).…”

Section: Introductionunclassified

“…Na literatura podem ser observados diversos exemplos do uso da análise de grupos aplicados a análise agronômica e estudos com reprodução de plantas (Murphy et al, 1986;Jolliffe et al, 1989;Brown, 1991;Dias-Filho et al, 1992, 1994White, 1993;Silveira et al, 2010).…”

Section: Introductionunclassified

Grupos funcionais de gramíneas forrageiras tropicais

et al. 2012

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“…Therefore, it was chosen a tiller at vegetative stage and from the same tussock of the previous tiller. However, the tiller in reproductive stage continued to be monitored for evaluation of senescence rate of its leaves (Silveira et al, 2010). Under this circumstance, the number of monitored tillers increased.…”

Section: Methodsmentioning

confidence: 99%

Characterization of tropical forage grass development pattern through the morphogenetic and structural characteristics

Rodrigues¹,

Júnior²,

Silva

et al. 2011

R. Bras. Zootec.

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-An experiment was carried out with the objective to evaluate growth pattern of tropical forage grass under free growth by using morphogenetic and structural characteristics with the expectation of using this study for forage grass evaluation protocol. The experimental area was established with two cultivars of Panicum maximum Jacq. (Mombaca and Aruana), a hybrid cultivar of P. maximum Jacq. and P. Infestum BRA-7102 (Massai), two cultivars of Brachiaria brizantha (A. Rich.) Stapf (Marandu and Xaraes) and Molasses grass (Melinis minutiflora Beauv.) and jaragua grass (Hyparrhenia rufa (Nees) Stapf.). The grasses were planted in 1.0-m 2 experimental units with 24 plants arranged in a completely randomized block design with three replications. Growth pattern of the grasses was evaluated through mass development, tiller mortality, development stage and leaf longevity. Development patterns differed significantly among groups of grasses, indicating that the same available resources can be used in different manners by grasses from the same genus and/or species.

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“…The expression of the three characteristics determines structural characteristics like leaf size, tiller population density and number of live leaves per tiller (LEMAIRE & CHAPMAN, 1996). Therefore, morphogenetic responses are determinants of variations in sward structure, assuming large importance in studies where the objective is to understand plant responses to variation in environmental conditions and management, and could be used to define similar functional groups of plants (SILVEIRA et al, 2010). Agronomic management practices (e.g.…”

Section: Lar) and Elongation (Ler) And Leaf Lifespan (Lls)mentioning

confidence: 99%