Factors affecting the hydrogen cyanide potential of white clover (Trifolium repens L.)

1987 ◽  
Vol 38 (6) ◽  
pp. 1053 ◽  
Author(s):  
PJ Vickery ◽  
JL Wheeler ◽  
C Mulcahy
Keyword(s):  
Light Intensity ◽  
White Clover ◽  
Trifolium Repens ◽  
Dry Matter ◽  
Late Pregnancy ◽  
Moisture Stress ◽  
Early Spring ◽  
Cool Temperature ◽  
Trifolium Repens L ◽  
Phosphorus Application

Pot experiments were used to determine the effects of age, light, temperature, mineral nutrition and wilting on the HCN potential (HCNp ) of white clover (Trifolium repens L.). HCNp, adjusted for pre-expenmental HCNp, was reduced by higher light intensity (505 v. 220 mg HCN kg-1 DM), by increased temperature (408 v. 317 mg HCN kg-1 DM) and by phosphorus application (382 v. 343 mg HCN kg-1 DM). These effects were largely explained by the hypothesis that HCNp diminished as the size and vigour of the plant increased, and the use of dry matter production as a covariate on HCNp removed the significant effects of light, temperature and phosphorus. In two experiments wilting plants prior to harvest increased HCNp by 15 and 24%, and reduced dry matter yield by 9 and 13%. HCNp declined curvilinearly as the white clover aged. The conditions shown to favour high HCNp, namely, immaturity, moisture stress, low light intensity, cool temperature, and inadequate P supply, are those which occur periodically in the late autumn and early spring of temperate climates. Sheep in late pregnancy at this time, could, if white clover comprises a substantial proportion of their diet, experience thiocyanate absorption as a consequence of HCN detoxication and hence increase the risk of goitri to the lamb.

Genotypic evaluation of introduced white clover (Trifolium repens L.) germplasm in New Zealand

2016 ◽  
Vol 67 (8) ◽  
pp. 897 ◽  
Author(s):  
M. Z. Z. Jahufer ◽  
J. L. Ford ◽  
D. R. W. Woodfield ◽  
B. A. Barrett
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Trifolium Repens ◽  
Dry Matter ◽  
Allelic Variation ◽  
Genotypic Variation ◽  
Dry Matter Yield ◽  
Breeding Lines ◽  
F1 Progeny ◽  
Trifolium Repens L

Optimal evaluation and use of introduced germplasm for species improvement is an ongoing challenge. Research was conducted to survey a select set of introduced white clover (Trifolium repens L.) germplasm from broad geographic origins to assess their genetic potential, based on F1 crosses to elite New Zealand cultivars. The bulk progeny generated from test crosses to Grasslands cultivars Demand, Sustain and Kopu II were evaluated at Palmerston North under rotational grazing by sheep. The replicated trial consisted of the 26 germplasm accessions, three cultivars used as maternal parents, and 78 F1 bulk progeny breeding lines. Three morphological traits and estimated seasonal dry matter yield were measured over four years. Significant (P < 0.05) genotypic variation was observed for all these traits among the parents and F1 progeny lines. F1 progeny lines with traits values greater than the cultivars were identified. Significant (P < 0.05) genotype-by-season (σ2gs) and genotype-by-year (σ2gy) interactions were estimated for dry matter yield. Principle component analysis of the F1 progeny-by-trait BLUP matrix identified 16 elite progeny lines with mean seasonal dry matter yield equal to or higher than the cultivars. Half of the lines had Demand as the cultivar parent, while only three had Kopu II as a parent. Fourteen of these progeny lines were derived from crosses to Australasian adapted germplasm. This study indicated that choice of adapted cultivar with which to cross is important, and introduced germplasm from Australasia is a valuable source of adaptive variation in these F1 progeny. More complex approaches may be needed to identify and use adaptive allelic variation from germplasm sources beyond Australasia.

Grasslands NuSiral white clover (Trifolium repens L.)

2002 ◽  
Vol 42 (7) ◽  
pp. 1023 ◽  
Author(s):  
J. F. Ayres ◽  
L. A. Lane ◽  
J. R. Caradus ◽  
P. T. P. Clifford
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Summer Rainfall ◽  
Moisture Stress ◽  
Annual Rainfall ◽  
Winter Rainfall ◽  
Mild Winter ◽  
Winter Activity ◽  
Trifolium Repens L ◽  
Cattle And Sheep

Grasslands NuSiral is a medium–large-leaf white clover (Trifolium repens L.) cultivar with intermediate growth habit (midway between open and erect and dense and prostrate), early flowering maturity and high growing point density. G. NuSiral possesses the plant-type attributes known to be desirable for broad adaptation to dryland pasture conditions in Australia and has been developed for cattle and sheep pastures in both summer rainfall and winter rainfall areas where average annual rainfall exceeds 750 mm. G. NuSiral is expected to provide enhanced stolon survival and autumn recovery in environments where summer moisture stress is present but not intense, and winter growth comparable to cv. Haifa where mild winter conditions allow the expression of G. NuSiral's winter activity.

scholarly journals ADAPTATION OF WHITE CLOVER TO MOISTURE STRESS

1987 ◽  
pp. 143-149 ◽  
Author(s):  
D.R. Woodfield ◽  
J.R. Caradus
Keyword(s):  
Plant Breeding ◽  
White Clover ◽  
Trifolium Repens ◽  
Moisture Stress ◽  
Root Characteristics ◽  
Trifolium Repens L ◽  
Selection For

In a series of four experiments, the w-seeding ability and shoot and root characteristics of dryland white clover populations (Trifolium repens L.), and the effect of selection for root characteristics within white clover were examined. There was little evidence that dryland populations were better at re-seeding than Huia, but dryland populations were more taprooted than populations collected from moister environments. Root morphologies of dryland populations were similar to that of Huia but were smaller leaved, although not as small leaved as Tahora. Evidence that selection for more taprooted, smaller-leaved types of white clover would be successful is also presented. Keywords: root type, drought, re-seeding, plant breeding, survival

Paths and mechanisms of moisture movements in detached leaves of white clover (Trifolium repens L.) II. Effects of lamina treatment losses of petiole moisture

1965 ◽  
Vol 16 (4) ◽  
pp. 591 ◽  
Author(s):  
W Shepherd
Keyword(s):  
Moisture Content ◽  
White Clover ◽  
Trifolium Repens ◽  
Dry Matter ◽  
Humid Air ◽  
Detached Leaves ◽  
Trifolium Repens L ◽  
Drying Rates

Drying rates of laminae and petioles of detached leaves of white clover (Trifolium repens L.) were measured after lamina treatments involving crushing, slitting, and drying in hot or humid air. Lamina transpiration of petiole moisture ceased at a lamina moisture content of approximately 1.5 g moisture per g dry matter (g/g). Delaying the drying of laminae to this level increased the rate of drying of petioles, but only to a petiole moisture content of approximately 4 g/g. Thereafter, lamina transpiration of petiole moisture, if it continued, was alternative to, but no more rapid than, transpiration direct from petiole surfaces. Implications concerning field drying of harvested clover are considered.

The pastoral significance, adaptive characteristics, and grazing value of white clover (Trifolium repens L.) in dryland environments in Australia: a review

2000 ◽  
Vol 40 (7) ◽  
pp. 1033 ◽  
Author(s):  
L. A. Lane ◽  
J. F. Ayres ◽  
J. V. Lovett
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Germplasm Conservation ◽  
Moisture Stress ◽  
Cattle Grazing ◽  
Poor Survival ◽  
Cold Environments ◽  
Economic Significance ◽  
Trifolium Repens L ◽  
Pasture Legume

The importance of white clover as a pasture legume of international significance has led to major investment in research on ecophysiology, germplasm conservation, and white clover improvement. Despite the agronomic merit and economic significance of white clover, Australia lacks white clover cultivars that possess adaptive characteristics for persistence in mixed swards under sheep and cattle grazing. The major problem with contemporary white clover cultivars is that clover biomass fluctuates widely from year to year. This lack of reliability, particularly in dryland environments, is largely due to poor survival during summer moisture stress that is common to much of the Australian white clover zone. Factors such as edaphic constraints, intolerance of grass competition and close grazing, and lack of winter growth in cold environments also influence the contribution of white clover to pasture performance. This paper considers the mechanisms of regeneration, adaptive characteristics, and significance of white clover for animal production, and reflects on breeding objectives for white clover improvement.

scholarly journals Response to selection for increased taproot diameter

1996 ◽  
Vol 6 ◽  
pp. 141-143
Author(s):  
D.R. Woodfield ◽  
J.R. Caradus ◽  
G.R. Cousins ◽  
T. Dunn
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Growth Habit ◽  
Leaf Size ◽  
Moisture Stress ◽  
Response To Selection ◽  
Short Term ◽  
Grazing Systems ◽  
Trifolium Repens L ◽  
Selection For

Increased taproot diameter is an important component in maintaining white clover (Trifolium repens L.) growth, nitrogen fixation and persistence during short-term moisture stress. Previous reports indicated selection for large taproot diameter would result in commensurate increases in leaf size and poorer growth habit. The current research investigates the response to selection for taproot diameter and the association between taproot diameter and leaf size in large-leaved clovers suited to dairy grazing systems. Taproot diameter increased by 2.4% per cycle while leaf size and growth habit were not significantly altered. Furthermore, while taproot diameter did not increase between cycle 2 and 3, the root index which measures the ratio of taproot diameter to leaf size increased linearly across all three cycles. These results suggest it is possible to select white clovers for dairying which have larger taproot diameter while maintaining a suitable growth habit. Keywords: dairying, drought, genetic improvement, root morphology, Trifolium repens L., white clover,

scholarly journals Long-term effects of pastoral fallowing on the distribution and performance of white clover (Trifolium repens L.) in a hill country pasture

1996 ◽  
Vol 6 ◽  
pp. 75-78 ◽  
Author(s):  
Z.N. Nie ◽  
I. Valentine ◽  
A.D. Mackay ◽  
D.J. Barker ◽  
J. Hodgson
Keyword(s):  
White Clover ◽  
Trifolium Repens ◽  
Dry Matter ◽  
Dry Matter Yield ◽  
Long Term Effects ◽  
Hill Country ◽  
Trifolium Repens L ◽  
And Performance

Previous work found that white clover (Trifolium repens L.) yield initially decreased, but subsequently increased following a pastoral fallow. The objective of this research was to quantify the response in herbage production and stolon characteristics of white clover up to 4 years after fallowing. Four treatments were used: fallowed 1990/91 (F4), fallowed 1991/92 (F3), fallowed 1993/94 (F1) and non-fallowed (F0). The fallowing period was between September and May. White clover dry matter yield (between 15/12/94 and 18/5/95) was significantly greater for the treatment F4 than F0 (P

Grasslands Trophy — a new white clover (Trifolium repens L.) cultivar with tolerance of summer moisture stress

2007 ◽  
Vol 47 (1) ◽  
pp. 110 ◽  
Author(s):  
J. F. Ayres ◽  
J. R. Caradus ◽  
R. D. Murison ◽  
L. A. Lane ◽  
D. R. Woodfield
Keyword(s):  
Seed Yield ◽  
White Clover ◽  
Trifolium Repens ◽  
Leaf Size ◽  
Moisture Stress ◽  
Yield Potential ◽  
Annual Rainfall ◽  
Progeny Testing ◽  
Eastern Australia ◽  
Trifolium Repens L

A breeding project has developed a new synthetic white clover (Trifolium repens L.) cultivar, Grasslands Trophy, that possesses tolerance of summer moisture stress in dryland pasture environments in the 850–1250 mm average annual rainfall temperate perennial pasture zone in eastern Australia. The breeding strategy used to develop Grasslands Trophy was an in situ breeding cycle for: (i) identifying and selecting superior genotypes, (ii) crossing elite germplasm and (iii) progeny testing derived breeding lines for the expression of key agronomic and grazing value traits. The primary selection criteria were early vigour, herbage yield, persistence and seed yield potential. Parental selection was also applied for seed yield, uniformity of leaf size, uniform flowering pattern and freedom from disease and virus symptoms. Grasslands Trophy is medium–large in leaf size with stable leaf size, combines intermediate stolon density with intermediate stolon thickness, and expresses high stolon survival and strong autumn regrowth following summer moisture stress. Grasslands Trophy has mid-season flowering maturity, intensive flowering prolificacy and high seed yield capability. Agronomic results from trials in northern New South Wales and New Zealand indicate that Grasslands Trophy has broad adaptation, expresses high summer and winter growth activity, and is reliably persistent for at least 4 years.

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