Variation in the response of Lolium genotypes to defoliation

1994 ◽  
Vol 45 (6) ◽  
pp. 1309 ◽  
Author(s):  
WJ Fulkerson ◽  
K Slack ◽  
KF Lowe
Keyword(s):  
Root Growth ◽  
Lolium Multiflorum ◽  
Selection Criterion ◽  
Evaluation Process ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Plant Water ◽  
Leaf Stage ◽  
Defoliation Frequency ◽  
Water Soluble Carbohydrate

A glasshouse study was undertaken to determine the effect of defoliation frequency (three times at one leaf stage or once at three leaf stage of the regrowth cycle) and height (20, 50 or 120 mm) on regrowth, plant water soluble carbohydrate (WSC) reserves and root growth of seven Lolium perenne and two Lolium multiflorum cultivars. The sensitivity to defoliation was in decreasing order: biennial, PI perennials (cv. Ellett, AN2327, LP30, LP31), P2 perennials (cv. Kangaroo Valley, Yatsyn, Pacific). The effect of frequent, compared to infrequent, defoliation was to suppress regrowth by l00%, 95% and 80%; stubble WSC (mg/plant) by 97, 89 and 81%; root DM (g/plant) by 76, 60 and 6%, for biennial, P1 and P2, respectively. The effect of defoliation height accentuated this response, with biennials defoliated frequently at 20 mm stubble height all dying. Under defoliation conditions producing optimal yield, the yield was positively related to sensitivity to defoliation, giving regrowths of 2.90, 2.68, 1.53 g DM per plant for biennial, P1 and P2 plants, respectively. In view of the marked defoliation by cultivar interaction, response to defoliation should be considered as a possible selection criterion in any evaluation process.

scholarly journals Response of Bromus valdivianus (Pasture Brome) Growth and Physiology to Defoliation Frequency Based on Leaf Stage Development

Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2058
Author(s):  
Iván P. Ordóñez ◽  
Ignacio F. López ◽  
Peter D. Kemp ◽  
Daniel J. Donaghy ◽  
Yongmei Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Stomatal Conductance ◽  
Root Growth ◽  
Water Soluble ◽  
Soluble Carbohydrates ◽  
Leaf Stage ◽  
Water Soluble Carbohydrates ◽  
Stage Development ◽  
Defoliation Frequency ◽  
Root Growth Rate

The increase in drought events due to climate change have enhanced the relevance of species with greater tolerance or avoidance traits to water restriction periods, such as Bromus valdivianus Phil. (B. valdivianus). In southern Chile, B. valdivianus and Lolium perenne L. (L. perenne) coexist; however, the pasture defoliation criterion is based on the physiological growth and development of L. perenne. It is hypothesised that B. valdivianus needs a lower defoliation frequency than L. perenne to enhance its regrowth and energy reserves. Defoliation frequencies tested were based on B. valdivianus leaf stage 2 (LS-2), leaf stage 3 (LS-3), leaf stage 4 (LS-4) and leaf stage 5 (LS-5). The leaf stage development of Lolium perenne was monitored and contrasted with that of B. valdivianus. The study was conducted in a glasshouse and used a randomised complete block design. For Bromus valdivianus, the lamina length, photosynthetic rate, stomatal conductance, tiller number per plant, leaf area, leaf weights, root growth rate, water-soluble carbohydrates (WSCs) and starch were evaluated. Bromus valdivianus maintained six live leaves with three leaves growing simultaneously. When an individual tiller started developing its seventh leaf, senescence began for the second leaf (the first relevant leaf for photosynthesis). Plant herbage mass, the root growth rate and tiller growth were maximised at LS-4 onwards. The highest leaf elongation rate, evaluated through the slope of the lamina elongation curve of a fully expanded leaf, was verified at LS-4. The water-soluble carbohydrates (WSCs) increased at LS-5; however, no statistical differences were found in LS-4. The LS-3 and LS-2 treatments showed a detrimental effect on WSCs and regrowth. The leaf photosynthetic rate and stomatal conductance diminished while the leaf age increased. In conclusion, B. valdivianus is a ‘six-leaf’ species with leaf senescence beginning at LS-4.25. Defoliation at LS-4 and LS-5 was optimum for plant regrowth, maximising the aboveground plant parameters and total WSC accumulation. The LS-4 for B. valdivianus was equivalent to LS-3.5 for L. perenne. No differences related to tiller population in B. valdivianus were found in the different defoliation frequencies.

Herbage yield, leafiness and water-soluble carbohydrate content, and silage composition and utilization in sheep of first- and second-cut Italian and Westerwolds ryegrasses (Lolium multiflorum Lam.)

1992 ◽  
Vol 72 (3) ◽  
pp. 755-762 ◽  
Author(s):  
P. Narasimhalu ◽  
H. T. Kunelius ◽  
K. B. McRae
Keyword(s):  
Dry Matter ◽  
Lolium Multiflorum ◽  
Nitrogen Retention ◽  
Carbohydrate Content ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Total N ◽  
Ammonium N ◽  
Voluntary Intake ◽  
Water Soluble Carbohydrate

Italian ryegrasses, cultivars Barmultra and Lemtal, and Westerwolds ryegrasses, cultivars Barspectra, Merwester and Promenade, (Lolium multiflorum Lam.) were harvested as first- and second-cut herbages and compared for yield, leafiness and water-soluble carbohydrate content during the 2-yr study. These herbages were conserved as silages and compared for chemical composition and for intake, digestibility, and total-N retention in sheep. First-cut ryegrass yielded more dry matter than second-cut ryegrass (3.3 vs. 2.6 t ha−1). First-cut ryegrass silages contained less dry matter and NDF, and sheep consumed less, but digested better and retained less total-N in comparison with second-cut ryegrass silage. Italian ryegrasses yielded less dry matter, were more leafy, contained less ADF, and were better digested compared with the Westerwolds ryegrasses. The herbage content of water-soluble-N, and the ratio of ammonium-N to total-N in silage were not different between the ryegrasses. Italian Barmultra was more leafy than Lemtal cultivar but no other significant differences were measured between these cultivars. Westerwolds Merwester yielded more dry matter, was less leafy, contained more NDF and ADF, and had lower voluntary intake, digestibility, and its total-N was less retained in sheep as compared with the Barspectra or Promenade Westerwolds ryegrass. Italian ryegrasses were superior in composition, voluntary intake, and digestibility to Westerwolds, but the latter were superior on the basis of yielding ability and efficiency of total-N utilization in sheep.Key words: Silage, ryegrass, intake, digestion, composition, Nitrogen retention

Defoliation frequency and genotype effects on stolon and root reserves in white clover

1998 ◽  
Vol 49 (6) ◽  
pp. 983 ◽  
Author(s):  
A. R. Lawson ◽  
P. W. G. Sale ◽  
K. B. Kelly
Keyword(s):  
White Clover ◽  
Large Fraction ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Starch Concentration ◽  
Nitrogen Concentrations ◽  
Defoliation Frequency ◽  
Water Soluble Carbohydrate ◽  
Nitrogen Contents ◽  
Principal Method

The effect of defoliation frequency (1 or 3 defoliations over a 42-day period) on the starch, water soluble carbohydrate (WSC), and nitrogen contents of 3 white clover cultivars (Haifa, Irrigation, and S184) was examined. The clover plants consisted of single stolons growing in a sand/scoria mix in an unheated glasshouse and fertilised weekly with a nitrogen-free solution. Starch concentrations ranged from 1·3% in frequently defoliated Haifa to 15·3% in infrequently defoliated S184 plants. However, there was no interaction between cultivar and defoliation frequency, with the starch concentration in S184 (11·2%) being twice that in Irrigation (6·0%) and 3 times that in Haifa (3·8%). The starch concentration was also less with frequent (3·7%) than with infrequent (10·3%) defoliation. The starch was localised in the old stolon material (12·2%), with lower levels of starch in both the young stolon (6·0%) and roots (4·0%). Furthermore, the cultivar and defoliation frequency effects on the starch concentrations were most pronounced in the old stolon. More frequent defoliation also resulted in a small reduction in the WSC and nitrogen concentrations in both the young and old stolons of Haifa, but not of Irrigation. It was concluded that although starch reserves were the principal method of reserve storage in white clover, WSC and nitrogen reserves will form a relatively large fraction of the reserve pool when starch reserves are depleted under conditions such as frequent defoliation.

scholarly journals Decreasing Defoliation Frequency Enhances Bromus valdivianus Phil. Growth under Low Soil Water Levels and Interspecific Competition

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1333
Author(s):  
Javier García-Favre ◽  
Yongmei Zhang ◽  
Ignacio F. López ◽  
Daniel J. Donaghy ◽  
Lydia M. Cranston ◽  
...  
Keyword(s):  
Soil Water ◽  
Block Design ◽  
Field Capacity ◽  
Water Levels ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Defoliation Frequency ◽  
Four Blocks ◽  
Water Soluble Carbohydrate ◽  
Reduced Water

Bromus valdivianus Phil. (Bv) is a water stress-tolerant species, but its competitiveness in a diverse pasture may depend on defoliation management and soil moisture levels. This glasshouse study examined the effect of three defoliation frequencies, based on accumulated growing degree days (AGDD) (250, 500, and 1000 AGDD), and two soil water levels (80–85% of field capacity (FC) and 20–25% FC) on Bv growth as monoculture and as a mixture with Lolium perenne L. (Lp). The treatments were applied in a completely randomised block design with four blocks. The above-ground biomass of Bv was lower in the mixture than in the monoculture (p ≤ 0.001). The Bv plants in the mixture defoliated more infrequently (1000 AGDD) showed an increase in root biomass under 20–25% FC compared to 80–85% FC, with no differences measured between soil water levels in the monoculture. Total root length was highest in the mixture with the combination of infrequent defoliation and 20–25% FC. Conversely, frequent defoliation treatments resulted in reduced water-soluble carbohydrate reserves in the tiller bases of plants (p ≤ 0.001), as they allocated assimilates mainly to foliage growth. These results provide evidence that B. valdivianus can increase its competitiveness relative to Lp through the enhancement of the root growth and the energy reserve in the tiller base under drought conditions and infrequent defoliation in a mixture.

Differences between related grasses, times of year and plant parts in digestibility and chemical composition

1996 ◽  
Vol 127 (3) ◽  
pp. 311-318 ◽  
Author(s):  
D. Wilman ◽  
Y. Gao ◽  
M. A. K. Altimimi
Keyword(s):  
Cell Wall ◽  
Lolium Multiflorum ◽  
Water Soluble ◽  
Italian Ryegrass ◽  
Soluble Carbohydrate ◽  
Meadow Fescue ◽  
Cell Content ◽  
Plant Parts ◽  
Dry Matter Digestibility ◽  
Water Soluble Carbohydrate

SUMMARYTrue dry matter digestibility, proportion of cell content, digestibility of cell wall, N and water-soluble carbohydrate were determined in eight related grasses in February, June and September in each of three years. In a separate experiment, true dry matter digestibility, proportion of cell content and digestibility of cell wall were determined in five plant parts of vegetative tillers of two grasses in February, April, June, August, October and December in each of two years.Perennial ryegrass (Lolium perenne) was the most digestible grass and tall fescue (Festuca arundinacea) and Westerwolds ryegrass (Lolium multiflorum var. Westerwoldicum) were the least digestible. Italian ryegrass (Lolium multiflorum) was high in proportion of cell content, but not in digestibility of cell wall. Meadow fescue (Festuca pratensis) was high in digestibility of cell wall, but low in proportion of cell content. Perennial ryegrass and hybrid ryegrass were high, and tall fescue low, in both proportion of cell content and digestibility of cell wall. Ryegrasses were lower than fescues in concentration of N and higher than the fescues in water-soluble carbohydrate; ryegrass × meadow fescue hybrids were intermediate between the parent species in N and watersoluble carbohydrate.Grass sampled in June and August was lower in both proportion of cell content and digestibility of cell wall than grass sampled at cooler times of year. Grass sampled in February was high in proportion of cell content and N, intermediate to high in digestibility of cell wall and intermediate in water-soluble carbohydrate.Expanding leaf blades of perennial and Italian ryegrass were higher than expanded blades and sheaths in digestibility of cell wall and similar to expanded blades and higher than sheaths in proportion of cell content. Cell wall was less digestible in the tip than in the middle and basal portions of expanded leaf blades.

Effect of defoliation interval on water-soluble carbohydrate and nitrogen energy reserves, regrowth of leaves and roots, and tiller number of cocksfoot (Dactylis glomerata L.) plants

2006 ◽  
Vol 57 (2) ◽  
pp. 243 ◽  
Author(s):  
L. R. Turner ◽  
D. J. Donaghy ◽  
P. A. Lane ◽  
R. P. Rawnsley
Keyword(s):  
Dry Matter ◽  
Dactylis Glomerata ◽  
Tiller Number ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Energy Reserves ◽  
Carbohydrate Reserves ◽  
Leaf Stage ◽  
Dactylis Glomerata L ◽  
Water Soluble Carbohydrate

This study investigated the influence of leaf stage-based defoliation interval on water-soluble carbohydrate and nitrogen energy reserve status, regrowth of leaves and roots, and tiller number of cocksfoot (Dactylis glomerata L.) cv. Kara plants up to 24 days (3.5-leaf stage) following defoliation. Treatments were based on defoliation intervals of 1-, 2-, and 4-leaf stages of regrowth, with treatments terminated when the 1-leaf defoliation interval had been completed 4 times, the 2-leaf interval 2 times, and the 4-leaf interval once. Selected plants were destructively harvested prior to commencement of treatments (H0), immediately following cessation of treatments (H1), and at 5 days (H2), 10 days (H3), and 24 days (H4) following H1. Leaf, root, and tiller dry matter yield were determined at each harvest event, as well as tiller number/plant. Levels of water-soluble carbohydrate and nitrogen reserves in plant stubble and roots were determined at each destructive harvest. Initiation and death of daughter tillers were monitored from H0 to the completion of the study. More frequent defoliation of cocksfoot plants resulted in reduced water-soluble carbohydrate assimilation and therefore leaf, root, and tiller dry matter accumulation during the subsequent recovery period. Defoliation at the 1-leaf stage severely limited the regrowth potential of cocksfoot plants, whereas defoliation at the 2-leaf stage was adequate for plant recovery, but did not maximise regrowth. The results of this study showed that a defoliation interval based on the 4-leaf stage maximises water-soluble carbohydrate reserves, tillering, and leaf and root dry matter yields. The priority sequence for allocation of water-soluble carbohydrate reserves followed the order of leaf growth, root growth, and tillering during the regrowth period. Nitrogen energy reserves were found to play a minor role in the regrowth of cocksfoot plants following defoliation.

Plant-soluble carbohydrate reserves and senescence - key criteria for developing an effective grazing management system for ryegrass-based pastures: a review

2001 ◽  
Vol 41 (2) ◽  
pp. 261 ◽  
Author(s):  
W. J. Fulkerson ◽  
D. J. Donaghy
Keyword(s):  
Dairy Cattle ◽  
Root Growth ◽  
Photosynthetic Capacity ◽  
Water Soluble ◽  
The Other ◽  
Soluble Carbohydrates ◽  
Soluble Carbohydrate ◽  
Carbohydrate Reserves ◽  
Water Soluble Carbohydrates ◽  
Water Soluble Carbohydrate

This review examines the use of changes in soluble carbohydrate reserves, and the onset of senescence in ryegrass (Lolium spp.), as key criteria for successfully managing an intermittent grazing system for dairy cattle. Ryegrass is a ‘3-leaf ’ plant; that is, only about 3 green leaves/tiller exist at any one time with the initiation of a new leaf coinciding with senescence of the oldest fourth leaf. Thus, grazing pasture older than 3 leaves/tiller will not only lead to wastage of pasture but also the senescent material will reduce overall quality of herbage. Based on this, the time taken for 3 new leaves/tiller to regrow sets the maximum grazing interval. On the other hand, in a well-utilised dairy pasture, most ryegrass leaf has been removed and the plant relies on stored water-soluble carbohydrate reserves to grow new shoots and hence regain photosynthetic capacity. If the concentration of water-soluble carbohydrates is inadequate, because there has been insufficient time to replenish in the previous inter-grazing period, regrowth will be suppressed and this may also affect persistence in the longer term. Immediately after grazing, water-soluble carbohydrate reserves decline as they are used to regrow new shoots, and root growth stops. It is not until about 3/4 of a new leaf/tiller has regrown that the plant has adequate photosynthetic capacity for growth and maintenance and only then does water-soluble carbohydrate replenishment and root growth commence. Studies have shown that subsequent regrowth is suppressed if plants are redefoliated before the 2 leaves/tiller stage of regrowth. Also, the levels of potassium and nitrogen (as nitrates and other non-protein nitrogen products) may be very high and cause metabolic problems in stock grazing such pasture. Thus, replenishment of water-soluble carbohydrate reserves sets the minimum grazing interval at 2 leaves/tiller. The rate of accumulation of water-soluble carbohydrates in the plant is a function of input through photosynthesis (source) and output to growth and respiration (sinks). Thus, apart from grazing interval (which sets the time to replenish water-soluble carbohydrate plant reserves), water-soluble carbohydrate storage will be influenced by incoming solar radiation (cloud cover, day length, pasture canopy density) and energy needs of the plant through respiration (temperature, canopy mass) and growth. Relating grazing interval to leaf number places the emphasis on the readiness of plants to be grazed rather than on the animals’ requirements, with leaf appearance interval depending primarily on ambient temperature. This allows grazing interval to be expressed in a similar morphological stage of growth, irrespective of season or location. Setting grazing interval on these 2 criteria has been shown to maximise growth and persistence of ryegrass and optimise the levels of most nutrients in pasture required by dairy cattle including protein, water-soluble carbohydrates, calcium, potassium and magnesium. Metabolisable energy and fibre do not change appreciably up to the 3 leaves/tiller stage of regrowth. On the other hand, grazing pasture before 2 leaves/tiller not only retards regrowth and reduces persistence, it provides forage too high in potassium and protein (nitrates) and too low in water-soluble carbohydrates for dairy cattle.

Effect of redefoliation on the regrowth and water soluble carbohydrate content of Lolium perenne

1994 ◽  
Vol 45 (8) ◽  
pp. 1809 ◽  
Author(s):  
WJ Fulkerson
Keyword(s):  
Lolium Perenne ◽  
Significant Relationship ◽  
Marked Effect ◽  
Water Soluble ◽  
Soluble Carbohydrate ◽  
Dramatic Effect ◽  
Leaf Stage ◽  
The Mean ◽  
Set Up ◽  
Water Soluble Carbohydrate

Plants of Lolium perenne, set up in a minisward in a glasshouse, were redefoliated at 3, 6 or 3 plus 6 days after defoliation at 2 or 5 cm stubble height. Regrowth, water soluble carbohydrate (WSC) content, and tillers per plant and tiller weight were measured. At the extreme, 70% of plants died when they were defoliated at 2 cm stubble height and redefoliated at 3 plus 6 days later. The mean total regrowth at the 3 leaves per tiller stage (and including the DM yield at each redefoliation) of the surviving plants was 4% of plants not defoliated and cut to the same stubble height. Redefoliation had a less marked effect on plants cut at 5 cm stubble height, reducing total regrowth by 55, 78 and 95%, for plants redefoliated at 3, 6 or 3 plus 6 days, respectively. There was a very significant relationship between tillers per plant and stubble WSC (mglplant) (Adj r2 = 0.90; P = 0.001) or stubble DM (g/plant) (Adj r2 = 0.89; P = 0.001) at the 1+ a leaf stage of regrowth on DM yields at the 3 stage of the regrowth cycle. These results confirm the dramatic effect of redefoliation on regrowth of ryegrass plants, and support the recommendation that grazing duration in the field be restricted to less than 3 days to prevent stock regrazing new leaf.

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