Genetic variation in water-soluble carbohydrate concentration in diverse cultivars of Dactylis glomerata L. during vegetative growth

2004 ◽  
Vol 55 (11) ◽  
pp. 1183 ◽  
Author(s):  
Y. Sanada ◽  
T. Takai ◽  
T. Yamada

The water-soluble carbohydrate (WSC) content of Dactylis glomerata L. (cocksfoot) during vegetative growth is lower than that of other temperate grasses. Variation in the WSC content of vegetative growth among cultivars was measured in order to assess the potential to improve forage quality. There were significant differences among cultivars for WSC content (P < 0.01) in all maturity groups. Average WSC content of the late (L) maturity group was higher than that of the early (E) and medium (M) maturity groups. Variation in the WSC content was largest among group L cultivars and smallest in group M. The WSC content of cultivars in groups M and L was consistent across 2 years (interactions between cultivars and years were not significant). Brown stripe infection was shown to reduce WSC content in susceptible cultivars. As a result of multiple regression analysis with WSC content as the dependent variable, dry matter content, heading date, thickness of stems, and resistance to brown stripe were selected as independent variables that were correlated with WSC. Therefore, variation for these traits must also be monitored in any program to increase WSC content in orchardgrass.

2006 ◽  
Vol 57 (2) ◽  
pp. 243 ◽  
Author(s):  
L. R. Turner ◽  
D. J. Donaghy ◽  
P. A. Lane ◽  
R. P. Rawnsley

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.


1997 ◽  
Vol 48 (7) ◽  
pp. 933 ◽  
Author(s):  
F. Volaire ◽  
F. Lelièvre

In rainfed Mediterranean areas, summer drought is the main factor affecting the persistence of perennial grasses. Most available cultivars of Dactylis glomerata (cocksfoot) exhibit low persistence in this environment; therefore, research is needed on the relationships between plant physiology and recovery after severe drought. In the field, we subjected a large range of populations and cultivars of cocksfoot to 3 months of drought followed by 3 weeks of rewatering. Principal component and cluster analysis discriminated 3 groups of genotypes: (1) late heading populations and cultivars of temperate origin (ssp. glomerata) that exhibited high tiller mortality in summer; (2) early heading populations of Mediterranean origin (ssp. hispanica) that survived well but had a low growth potential; (3) very early heading Mediterranean cultivars (ssp. glomerata × hispanica) that survived and recovered actively. The study of bases of youngest enclosed leaves (surviving organs) showed that osmotic potential in living bases was not significantly different between groups of populations; dry matter content was higher in bases of hispanica populations at the onset of drought; total water-soluble carbohydrate and fructan contents increased as drought progressed and reached 35-40% of dry matter in bases at the end of the drought. Drought survival was best correlated with both the ratio between low and high weight fructans in July (summer) and the heading date (R2 = 0·75, P < 0·001). Recovery yield after autumn rewatering was highly correlated with both of these variables and the dry matter content in leaf bases in June (R2 = 0·75, P< 0·001), which may be associated with levels of summer dormancy. These results emphasise the role of ontogeny in drought resistance and can be used to predict plant survival in a large range of populations of cocksfoot.


Weed Science ◽  
1973 ◽  
Vol 21 (3) ◽  
pp. 212-217 ◽  
Author(s):  
J. W. Shriver ◽  
S. W. Bingham

Bromacil (5-bromo-3-sec-butyl-6-methyluracil) had no effect on germination but reduced growth of emerging shoots of orchardgrass (Dactylis glomerataL. ‘Virginia Common’) more than Kentucky bluegrass (Poa pratenseL. ‘Merion’). Fresh weight gain and transpiration were reduced in orchardgrass seedlings at 0.125 ppmw of bromacil whereas 1.0 ppmw were required for reductions in bluegrass. Photosynthesis was inhibited in both plants; however, bluegrass recovered in 6 days. Water soluble carbohydrate content was greater and was not reduced as much by bromacil in bluegrass compared with orchardgrass. Absorption of 2-14C-bromacil from solution and translocation to shoots was directly related to transpiration rate. Bromacil was translocated acropetally from sheath and foliar treatments. Higher metabolic conversion of 2-14C-bromacil occurred in bluegrass compared to orchardgrass. Metabolites detected in plant extracts were 5-bromo-3-(2-hydroxy-1-methylpropyl)-6-methyluracil and an unknown. Traces of 3-sec-butyl-6-methyluracil and 5-bromo-3-sec-butyl-6-hydroxymethyluracil were also detected. Bluegrass tolerance involved high carbohydrate levels in tissues, hydroxylation of bromacil, and recovery of photosynthesis.


1973 ◽  
Vol 13 (61) ◽  
pp. 165 ◽  
Author(s):  
PJ Michell

Neutral detergent fibre (NDF), acid detergent fibre (ADF) and water soluble carbohydrate (WSC) levels were determined on 80 samples of known apparent dry matter digestibility (DMD) and voluntary intake of dry matter (DMI). The pastures consisted of regrowths of six species: Trifolium repens (white clover cv. Grasslands Huia), Lolium perenne x L. multiflorum (short rotation ryegrass c.v Grasslands Manawa), Lolium perenne (long rotation ryegrass cv. Grasslands Ariki), Lolium perenne (perennial ryegrass cv. Tasmania No. I), Dactylis glomerata (cocksfoot cv. Currie) and Dactylis glomerata (cocksfoot cv. Grasslands Apanui), cut eight times between May 1969 and August 1970. Overall, white clover had a lower NDF and a lower WSC content than the ryegrasses but both groups had similar ADF contents. Cocksfoots had higher NDF and ADF, and lower WSC contents than the ryegrasses. NDF and ADF could be used to predict the DMD of all species in all seasons with residual standard deviations (RSD) of 3.0 and 3.2 DMD units (per cent) respectively. No significant relations (P < 0.05) were present between DMD and WSC content. Seasonal differences were present in the relations between DMI and chemical composition. The RSD of the overall regressions of intake with NDF, ADF, and WSC contents were 9.3, 9.4, and 8.9 DMI units (g/day/kg0.75) respectively. Within seasons, DMI was best predicted by regressions with detergent fibre content and here the RSD had a range of 3.4 to 5.2 DMI units. Within species over all seasons, DMI was predicted best by regressions with WSC content and the RSD had a range of 5.7 to 7.9 DMI units. The usefulness of the chemical composition measurements in explaining the reason for the low intakes, previously found with winter pasture, is discussed.


1998 ◽  
Vol 1998 ◽  
pp. 150-150
Author(s):  
J. K. Margerison ◽  
D. V. Illingworth ◽  
D. W Jackson

Increasing importance of home grown proteins has resulted in a renewed interest in grass-clover mixed swards. The objective of this experiment was to asses the effect of wilting on effluent production levels, polluting potential of the silage effluent, and silage quality in grass and grass-clover mixed swards.Perennial rye grass (G) and a grass clover mixed sward (0.75 perennial ryegrass, 0.25 white clover, GC) was cut in mid may. The G and GC was then precision chopped and ensiled in experimental silos at 0, 24 and 48 hours following cutting, with 5 replicate silos of each silage being made at each time period. The silage effluent was collected, the quantity produced was recorded and the biochemical oxygen demand and the chemical oxygen demand was measured. The silage was allowed to ferment followed by which the silage was sub-samples and composite samples 3 of each silage were analyzed for dry matter content, crude protein levels, neutral detergent fibre, water soluble carbohydrate, pH, lactic acid, acetic acid, proprionc acid, butyric acid, total volatile acid levels. The data were analyzed using the general linear model ANOVA in Minitab.


1970 ◽  
Vol 75 (2) ◽  
pp. 293-300 ◽  
Author(s):  
D. I. H. Jones

SUMMARYThe ensiling characteristics of grasses and of red clover were examined by means of a small scale vacuum silage technique. Eight grasses, comprising three varieties each of perennial ryegrass and cocksfoot and two varieties of timothy, were evaluated after application of two levels of nitrogen fertilizer. Three varieties of red clover were evaluated at two stages of growth with and without sucrose supplementation during ensiling.Perennial ryegrass varieties contained more water soluble carbohydrates than cocksfoot and timothy varieties. At the low level of fertilizer N, silages made from the first cut in mid-May were all well preserved 3 weeks after ensiling. At the high level of fertilizer only perennial ryegrass varieties and S345 cocksfoot were well preserved. After ensiling for 14 weeks perennial ryegrass silages remained well preserved but secondary fermentation in the cocksfoot and timothy varieties resulted in poor preservation. Silages made from the second cut at the end of May were all badly preserved except for silage made from tetraploid ryegrass at the low nitrogen level.Significant correlations were established between the water soluble carbohydrate content of the grasses and the quality of the resulting silage, but herbage dry-matter content and buffering capacity were not significantly correlated with silage quality.The red clover varieties were lower in water soluble carbohydrate and higher in buffering capacity than the grasses. Although the silages from red clover were well preserved they were of high pH. Supplementation with sucrose significantly reduced pH and ammonia content and increased lactic-acid content.


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