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

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
B. Biligetu ◽  
Bruce Coulman

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.

2016 ◽  
Vol 64 (1) ◽  
pp. 70-92 ◽  
Author(s):  
Mait Lang ◽  
Ando Lilleleht ◽  
Mathias Neumann ◽  
Karol Bronisz ◽  
Samir G. Rolim ◽  
...  

Abstract A generic regression model for above-ground biomass of forest stands was constructed based on published data (R2 = 0.88, RSE = 32.8 t/ha). The model was used 1) to verify two allometric regression models of trees from Scandinavia applied to repeated measurements of 275 sample plots from database of Estonian Network of Forest Research (FGN) in Estonia, 2) to analyse impact of between-tree competition on biomass, and 3) compare biomass estimates made with different European biomass models applied on standardized forest structures. The model was verified with biomass measurements from hemiboreal and tropical forests. The analysis of two Scandinavian models showed that older allometric regression models may give biased estimates due to changed growth conditions. More biomass can be stored in forest stands where competition between trees is stronger. The tree biomass calculation methods used in different countries have also substantial influence on the estimates at stand-level. A common database of forest biomass measurements from Europe in similar to pan-tropical tree measurement data may be helpful to harmonise carbon accounting methods.


2006 ◽  
Vol 86 (3) ◽  
pp. 745-747 ◽  
Author(s):  
Bruce Coulman

Success hybrid bromegrass was selected from populations produced by backcrossing smooth bromegrass (Bromus inermis Leyss.) with hybrid populations resulting from crosses between meadow bromegrass (Bromus riparius Rehm.) and smooth bromegrass. Success has a unique array of plant characteristics, some similar to meadow bromegrass, and others more similar to smooth bromegrass; overall, it more closely resembles smooth brome. In regional trials in the prairie provinces of western Canada, Success produced forage yields greater than meadow brome, but lower than smooth bromegrass. In the drier brown soil zone of the prairie provinces, Success was superior to both meadow and smooth bromegrass in forage yield. It was superior to smooth bromegrass in regrowth after cutting and had lower concentrations of acid-detergent fiber than meadow bromegrass. Key words: Hybrid bromegrass, Bromus riparius × Bromus inermis, cultivar description


2000 ◽  
Vol 80 (3) ◽  
pp. 551-557 ◽  
Author(s):  
Yasas S. N. Ferdinandez ◽  
Bruce E. Coulman

Three hybrid populations between meadow bromegrass (Bromus riparius Rehm.) and smooth bromegrass (Bromus inermis Leyss.) have been developed using recurrent selection for vigor, uniformity of growth and floret fertility. The objective of this study was to use morphological characters to characterize the three hybrid populations (S-9197, S-9073, and S-9183) and the two parental species. Tiller heights did not differ among the hybrids and the parental species. Leaf-to-stem ratio of the hybrids was intermediate to that of the parents. Tiller density, panicle density and dry matter yield of the hybrids were more similar to those of smooth bromegrass. Leaf pubescence densities of the hybrids were higher than the parental species, but pubescence lengths closely resembled meadow bromegrass. Leaf area index (LAI) of the hybrids was lower than smooth bromegrass, and resembled meadow bromegrass. Lowest brown leaf spot ratings were observed in meadow bromegrass, while the hybrids were similar to smooth bromegrass. In general, the hybrid populations showed some individual characteristics similar to each of the parental species and, thus, can be characterized as being intermediate to the parental species. Furthermore, several of the differences among the hybrid populations can be attributed to the selection criteria that were used to develop these populations. Key words: Bromus, smooth bromegrass, meadow bromegrass, hybrid bromegrass, morphological characteristics


1996 ◽  
Vol 76 (4) ◽  
pp. 763-771 ◽  
Author(s):  
J. R. Pearen ◽  
V. S. Baron

The value of smooth bromegrass (Bromus inermis Leyss.)–alfalfa (Medicago sativa L.) mixtures for pastures in central Alberta is limited by poor seasonal distribution of yield and low alfalfa persistence. Regrowth of meadow bromegrass (Bromus riparius Rehm.) exceeds that of smooth bromegrass. The effect of these grasses on yield, seasonal distribution and sward composition when grown in mixtures with alfalfa was evaluated. The DM yield of binary mixtures of Carlton or Manchar smooth bromegrass, or Regar meadow bromegrass with Peace or Beaver alfalfa was examined under a four-cut system at three sites in central Alberta for 3 yr. Annual yield was similar at all sites. Alfalfa cultivar did not consistently affect yield, but annual yield of meadow bromegrass-mixtures was 9 to 19% higher than mixture containing smooth bromegrass at Lacombe. Summer and fall production of meadow bromegrass mixtures was 18 to 53% and 40 to 69% greater (P ≤ 0.0001) than smooth bromegrass mixtures. Tiller weight of smooth bromegrass equalled or exceeded that of meadow bromegrass, so superior regrowth of meadow bromegrass mixtures was due to higher tiller density. Over 3 yr, annual yield of the alfalfa component was similar in smooth bromegrass- and meadow bromegrass mixtures, but alfalfa yield decreased (P ≤ 0.0001) 43 to 70% due to dramatic declines in alfalfa stem density. Competition from the associated grass and frequent defoliation reduced alfalfa longevity. Key words: Smooth bromegrass, Bromus inermis Leyss., alfalfa, Medicago sativa L., mixtures, pasture, sward structure


1995 ◽  
Vol 75 (2) ◽  
pp. 429-436 ◽  
Author(s):  
J. R. Pearen ◽  
V. S. Baron ◽  
I. W. Cowan

Dry matter yield of smooth bromegrass (Bromus inermis Leyss.) - alfalfa (Medicago sativa L.) mixtures is restricted by short growing seasons and poor legume persistence in the Aspen Parklands of western Canada. Meadow bromegrass (Bromus riparius Rehm.) has recently gained acceptance, but comparative information on smooth and meadow bromegrass in grass-alfalfa mixtures is unavailable. We examined DM yield of binary grass-legume mixtures containing either Carlton or Manchar smooth bromegrass or Regar meadow bromegrass with Peace or Beaver alfalfa under a two-cut hay-management system at four sites in central Alberta for 3 yr. Annual DM yield was 40% greater (P ≤ 0.0001) at sites near Lacombe (7570 kg ha−1) than at Bluffton and Vegreville (5420 kg ha−1). Dry matter yield of smooth bromegrass mixtures (8020 kg ha−1) was 20% higher (P ≤ 0.01) than that of meadow bromegrass mixtures (6690 kg ha−1) near Lacombe. Alfalfa DM yield was 2.1 times higher at Bluffton and Vegreville (2770 kg ha−1) than near Lacombe (1300 kg ha−1). Near Lacombe, alfalfa regrowth was suppressed (P ≤ 0.0001) by smooth bromegrass, which had 2.3 times larger (P < 0.001) tillers than meadow bromegrass at first cut. At Bluffton and Vegreville, DM yield of meadow bromegrass mixtures equalled or exceeded (P ≤ 0.05) that of smooth bromegrass mixtures. Although first-cut tiller weight of smooth bromegrass was 73% more (P ≤ 0.0001) than that of meadow bromegrass at Bluffton and Vegreville, tiller density of meadow bromegrass was 1.7 times greater (P ≤ 0.0001) than that of smooth bromegrass. Results indicate that smooth bromegrass mixtures were superior to meadow bromegrass mixtures for hay production at moist fertile locations, despite reduced alfalfa persistence. At drier or less fertile sites, however, DM yield of meadow bromegrass mixtures was higher than that of smooth bromegrass mixtures when weather conditions for regrowth were favourable. Key words: Bromegrass-alfalfa mixtures, hay, parklands


2004 ◽  
Vol 84 (3) ◽  
pp. 815-817 ◽  
Author(s):  
Bruce Coulman

Knowles was selected from hybrid populations resulting from crosses between meadow bromegrass (Bromus riparius Rehm.) and smooth bromegrass (Bromus inermis Leyss.). It has a unique array of plant characteristics, some similar to meadow bromegrass, and others more similar to smooth bromegrass. In regional trials, Knowles produced hay yields greater than meadow brome, but lower than smooth bromegrass. It was superior to smooth bromegrass in regrowth after cutting. For steer grazing performance, Knowles was equal or superior to its parental species, perhaps due to its lower fiber concentrations at vegetative growth stages. Key words: Hybrid bromegrass, Bromus riparius × Bromus inermis, cultivar description


2017 ◽  
Vol 23 (2) ◽  
Author(s):  
AFSHAN ANJUM BABA ◽  
SYED NASEEM UL-ZAFAR GEELANI ◽  
ISHRAT SALEEM ◽  
MOHIT HUSAIN ◽  
PERVEZ AHMAD KHAN ◽  
...  

The plant biomass for protected areas was maximum in summer (1221.56 g/m2) and minimum in winter (290.62 g/m2) as against grazed areas having maximum value 590.81 g/m2 in autumn and minimum 183.75 g/m2 in winter. Study revealed that at Protected site (Kanidajan) the above ground biomass ranged was from a minimum (1.11 t ha-1) in the spring season to a maximum (4.58 t ha-1) in the summer season while at Grazed site (Yousmarag), the aboveground biomass varied from a minimum (0.54 t ha-1) in the spring season to a maximum of 1.48 t ha-1 in summer seasonandat Seed sown site (Badipora), the lowest value of aboveground biomass obtained was 4.46 t ha-1 in spring while as the highest (7.98 t ha-1) was obtained in summer.


2016 ◽  
Vol 13 (11) ◽  
pp. 3343-3357 ◽  
Author(s):  
Zun Yin ◽  
Stefan C. Dekker ◽  
Bart J. J. M. van den Hurk ◽  
Henk A. Dijkstra

Abstract. Observed bimodal distributions of woody cover in western Africa provide evidence that alternative ecosystem states may exist under the same precipitation regimes. In this study, we show that bimodality can also be observed in mean annual shortwave radiation and above-ground biomass, which might closely relate to woody cover due to vegetation–climate interactions. Thus we expect that use of radiation and above-ground biomass enables us to distinguish the two modes of woody cover. However, through conditional histogram analysis, we find that the bimodality of woody cover still can exist under conditions of low mean annual shortwave radiation and low above-ground biomass. It suggests that this specific condition might play a key role in critical transitions between the two modes, while under other conditions no bimodality was found. Based on a land cover map in which anthropogenic land use was removed, six climatic indicators that represent water, energy, climate seasonality and water–radiation coupling are analysed to investigate the coexistence of these indicators with specific land cover types. From this analysis we find that the mean annual precipitation is not sufficient to predict potential land cover change. Indicators of climate seasonality are strongly related to the observed land cover type. However, these indicators cannot predict a stable forest state under the observed climatic conditions, in contrast to observed forest states. A new indicator (the normalized difference of precipitation) successfully expresses the stability of the precipitation regime and can improve the prediction accuracy of forest states. Next we evaluate land cover predictions based on different combinations of climatic indicators. Regions with high potential of land cover transitions are revealed. The results suggest that the tropical forest in the Congo basin may be unstable and shows the possibility of decreasing significantly. An increase in the area covered by savanna and grass is possible, which coincides with the observed regreening of the Sahara.


2004 ◽  
Vol 84 (1) ◽  
pp. 125-127
Author(s):  
Marcelo R. A. de Araujo ◽  
B. E. Coulman

To determine the nature and extent of inflation of estimates of heritabilities by parent-offspring regression methods, 40 clones of meadow bromegrass (Bromus riparius Rehm.) and their half-sib progenies were studied in completely randomized block design trials, with six replications in Saskatoon and Melfort, Canada. Clones and progenies were evaluated for dry matter yield, seed yield, plant height, fertility index and harvest index. The results of the analysis showed a consistent inflation of heritability estimates derived from the simple parent-offspring regression, when compared to the regression estimate by variance-covariance analysis. The two methods successfully removed the environmental covariances from the estimates. However, in the simple regression analysis, error covariance was not removed from the numerat or; therefore, heritabilities estimated by this methodology were higher than those estimated by the variance-covariance method. It was concluded that estimates derived from variance-covariance analysis provide less biased estimates of heritability. Key words: Regression analysis, heritability, meadow bromegrass


2021 ◽  
Vol 21 ◽  
pp. 100462
Author(s):  
Sadhana Yadav ◽  
Hitendra Padalia ◽  
Sanjiv K. Sinha ◽  
Ritika Srinet ◽  
Prakash Chauhan

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