Responses of Three Bromegrass (Bromus) Species to Defoliation under Different Growth Conditions

Abstract

Bromegrass species are important forage crops in temperate regions of world. This study compared responses of three bromegrass species to defoliation in the greenhouse and field to determine if the former could predict responses in the latter. Experiments were conducted in 2006 and 2007 in Saskatoon (52°07′N,106°38′W), Canada on meadow bromegrass (Bromus ripariusRehm.), smooth bromegrass (Bromus inermisLeyss.), and hybrid bromegrass (B. ripariusX B.inermis) following defoliation to 5 cm stubble height. When defoliated at the vegetative stage, above-ground biomass was similar among the three species in the field, but meadow bromegrass produced greater above-ground biomass than smooth bromegrass in the greenhouse. When defoliated at the stem elongation stage, meadow bromegrass produced greater above-ground biomass than smooth bromegrass in both environments. In the field, for all defoliation treatments, tiller number was greatest in meadow bromegrass, intermediate in hybrid bromegrass, and least in smooth bromegrass. In the greenhouse, however, the three species did not differ in tiller number. Similar results were found for below-ground biomass. Thus, testing the effect of defoliation in the greenhouse environment did not accurately predict the effect in the field environment.

Influence of Richness and Seeding Density on Invasion Resistance in Experimental Tallgrass Prairie Restorations

“…Rhizome production is affected by similar processes to those that affect seed production, such as nutrient availability and interspecific competition (Otfinowski et al 2007), and is also sensitive to changes in light intensity and quality, with tiller density increasing with increasing light intensity (Biligetu and Coulman 2010). Light conditions may have differed among the treatments, although this variable was not measured.…”

Water-Soluble Carbohydrate Recovery in Pastures of Perennial Ryegrass (Lolium perenne L.) and Pasture Brome (Bromus valdivianus Phil.) Under Two Defoliation Frequencies Determined by Thermal Time

“…where T max is the daily maximum air temperature, T min is the daily minimum air temperature, and T base is the temperature below which the observed process does not occur. A base temperature of 5 • C was used for both species, and the temperature accumulated from day 1 to day n [22,23]. The air temperature was measured at 150 cm high above the ground level, and it was taken from the meteorological station close to the field experiment.…”

The Use of Thermal Time to Describe and Predict the Growth and Nutritive Value of Lolium perenne L. and Bromus valdivianus Phil

“…where T max is the maximum daily air temperature at 1.5 m above ground level, T min is the minimum daily air temperature, and T base is the temperature at which cellular activity stops [19]. The base growth temperature (T base ) for forage species in this study was 5 • C, as determined by previous studies performed under similar conditions [17,20].…”