Agronomic, morphogenic and structural characteristics of tropical forage grasses in northeast Brazil

Abstract

The objective of this study was to assess the agronomic, morphogenic and structural characteristics of tropical forage grasses during the establishment phase and throughout the second year in northeast Brazil. The treatments included 9 grasses: Brachiaria humidicola (koronivia grass), Brachiaria hybrid cv. Mulato, Brachiaria brizantha cvv. Piatã, Xaraés and Marandu, Brachiaria ruziziensis (ruzi grass), Brachiaria decumbens (signal grass), Panicum hybrid cv. Massai and Andropogon gayanus (gamba grass). The grasses were planted in a randomized complete block design with 4 replications. The following parameters were measured: total forage production, leaf:stem ratio, tiller population density, number of dead tillers, leaf emergence rate, phyllochron, leaf elongation rate, stem elongation rate, rate of leaf senescence, final length of leaf blade and life-span of leaves. In the establishment year, cv. Mulato produced the highest forage yields, followed by cvv. Xaraés and Massai, with gamba grass and koronivia grass worst. In the second year, cvv. Mulato, Xaraés and Marandu, and gamba grass showed highest forage production, while cvv. Massai and Piatã produced the least. All grasses showed a marked drop in production during the dry season. Cultivar Massai consistently had the highest leaf:stem ratio. The morphogenic and structural characteristics differed according to cultivar and season of the year. In general, leaf emergence rate, leaf elongation rate, stem elongation rate, rate of leaf senescence, final length of the leaf blade, number of live leaves per tiller and density of living tillers were higher in the rainy season, while the phyllochron and life-span of leaves were higher in the dry season. The results of this research highlight the potential of the Brachiaria cultivars Mulato and Xaraés, gamba grass and Panicum cv. Massai in subhumid Maranhão, northeast Brazil. ResumenEl estudio se realizó en el nordeste de Brasil con el objetivo de evaluar las características agronómicas, morfogénicas y estructurales de 9 gramíneas forrajeras tropicales durante la fase de establecimiento y el primer año de producción. Los tratamientos incluyeron: Brachiaria humidicola, Brachiaria híbrido cv. Mulato, Brachiaria brizantha cvs. Piatã, Xaraés y Marandu, Brachiaria ruziziensis, Brachiaria decumbens, Panicum híbrido cv. Massai y Andropogon gayanus. Las gramíneas fueron sembradas en un diseño de bloques completos al azar con 4 repeticiones. Se midieron los parámetros siguientes: producción total de forraje; relación hoja:tallo; densidad populacional de rebrotes; número de rebrotes muertos; tasa de aparición foliar; filocrono; tasas de elongación de hojas y tallos; tasa de senescencia foliar; longitud final de la lámina foliar; y duración de la vida útil de las hojas. En el año de establecimiento, Brachiaria hí-brido cv. Mulato produjo los mayores rendimientos de forraje, seguido por B. brizantha cv. Xaraés y Panicum híbrido cv. Massai, siendo A. gayanus y B. humidicola los de peor desempeño. En el segundo año, los cvs. M...

Structure of massai grass pasture grazed on by sheep supplemented in the dry season

“…In addition, this cultivar has rapid establishment, is more tolerant to infertile soils, and has good resistance to leafhopper infestation (Rodrigues et al 2014). In addition, this cultivar has rapid establishment, is more tolerant to infertile soils, and has good resistance to leafhopper infestation (Rodrigues et al 2014).…”

The anthochron as a building block of flower development

“…The slope of the linear regression represents the flower opening rate, and the anthochron can be estimated as the inverse of the slope of the regression, i.e., anthochron = 1/a, with unit of time per flower (Schwab et al, 2014). This approach is similar to the one used to estimate the phyllochron (Rosa et al, 2009;Costa et al, 2014;Martins et al, 2014). …”

“…During the vegetative phase, structural organs, such as leaves, stem, and roots, are differentiated and grow. Plant development during this phase has been widely described using the concept of phyllochron (Streck et al, 2007;Rosa et al, 2009;Costa et al, 2014;Martins et al, 2014), defined as the time interval between the appearance of two successive leaves on the stem (Wilhelm & McMaster, 1995;Skinner & Nelson, 1992). From this perspective, the vegetative phase can be understood as the result of the accumulation of phyllochron units, which are considered the building blocks of vegetative development.…”

“…From this perspective, the vegetative phase can be understood as the result of the accumulation of phyllochron units, which are considered the building blocks of vegetative development. The phyllochron concept has been widely applied to annual and perennial crops (Streck et al, 2007;Rosa et al, 2009;Streck et al, 2012;Costa et al, 2014;Martins et al, 2014;Rodrigues et al, 2014;Davidson et al, 2015), and genetic and environmental factors that affect the phyllochron, as temperature, soil moisture, and photoperiod, have also been identified (Kirby, 1995). However, concerning the reproductive phase, less effort has been dedicated to describe flower development, especially with regard to the flower opening rate on inflorescences.…”

Caracterização e restrições de forrageiras indicadas para as diferentes espécies de animais de produção – revisão

“…Toda planta forrageira apresenta determinadas vantagens e limitações. Todavia para que haja produção e consequentemente correta utilização da pastagem escolhida, é fundamental que se estabeleçam inicialmente, níveis de fertilidade e manejos adequados para cada forrageira em questão e sua determinada espécie animal (RODRIGUES et al, 2014).…”