Wether bioassay of annual pasture legumes. I. Oestrogenic activity in Medicago tribuloides Desr. var. Cyprus* relative to four strains of Trifolium subterraneum L.

1964 ◽  
Vol 15 (4) ◽  
pp. 520 ◽  
Author(s):  
AJ Millington ◽  
CM Francis ◽  
NR McKeown

The grazing of pasture swards of Cyprus barrel medic and of four strains of subterranean clover resulted in increases of wether teat length similar to those produced by injections of a synthetic oestrogen, diethylstilboestrol. Oestrogenic activity of the medic, as measured by increase in wether teat length, was less than that of the Yarloop and Dwalganup strains of subterranean clover, but similar to that of the Mt. Barker strain. Coumestrol appears to be the principal oestrogenic substance in the medic. The coumestrol contents of Cyprus and commercial barrel medics were similar but varied at different localities. The low coumestrol content of the subterranean clovers suggests that it is not an important oestrogen in this species. ____________________ *Cyprus barrel medic. During the joint FAO–CSIRO collecting expedition in 1950–1951, J. F. Miles collected barrel medic, C.P.J. 13914, in Cyprus, and portion of the seed was passed to D. Symon at the Waite Agricultural Research Institute, Adelaide. A programme, commenced in 1950, to extend the legume belt into the lower rainfall districts of Western Australia, indicated the need for an earlier-flowering medic, and Symon suggested testing the Cyprus introductjon. Encouraging results from sward tnals conducted by the Institute of Agriculture, University of Western Australia, resulted in a programme of seed increase and large-scale commercial production of the Cyprus strain. The Cyprus strain flowers 4 weeks earlier than the commercial and 5 weeks before M. tr ibuloides 173, and is proving a very satisfactory legume on a wide range of soils in Western Australia.

1963 ◽  
Vol 14 (2) ◽  
pp. 206 ◽  
Author(s):  
JN Black

This paper describes two experiments analysing the recovery from defoliation of subterranean clover varieties grown in swards in large seed boxes at the Waite Agricultural Research Institute, Adelaide. The first experiment examined the way in which the six common commercial varieties recovered from a single severe defoliation, and showed that under these conditions they can be placed in three groups: Yarloop and Clare are tall, high-yielding varieties with few, large leaves, recovering slowly from defoliation; Tallarook and Dwalganup are prostrate varieties, lower-yielding, with many small leaves, recovering rapidly after defoliation; Bacchus Marsh and Mount Barker are intermediate in all respects. In the second experiment mixed swards of equal numbers of Yarloop and Tallarook plants were grown under three treatments: A, no defoliation; B, defoliated twice at a height which removed the higher Yarloop canopy but left the lower Tallarook plants untouched; C, defoliated twice at a height which removed the canopies of both varieties. Measurement of dry weight on four occasions after each defoliation showed that in the undefoliated treatment, all Tallarook plants died by the end of the experiment. In the defoliated treatments, the removal of the Yarloop canopy resulted in only a temporary improvement in the illuniination in which the Tallarook plants grew, and their dry weight and plant numbers progressively declined. Dry weight changes in the Tallarook component were shown to be dependent on the light energy available to it, which was in turn determined by the light-absorbing capacity of the superior Yarloop canopy. In mixed swards, the ability of Yarloop to re-establish quickly a leaf canopy above that of Tallarook appeared to explain its success when defoliated.


1955 ◽  
Vol 8 (3) ◽  
pp. 330 ◽  
Author(s):  
JN Black

An experiment is described in which the growth of subterranean clover (Trifolium subterraneum L.) in the early vegetative stage was measured over 52 consecutive weekly periods. To eliminate possible trends of growth rates with age, plants of comparable morphological stage were used for each period. The variety Bacchus Marsh was grown in pot culture in the open at the Waite Agricultural Research Institute, Adelaide, South Australia.


2012 ◽  
Vol 63 (9) ◽  
pp. 840 ◽  
Author(s):  
C. K. Revell ◽  
M. A. Ewing ◽  
B. J. Nutt

The south-west of Western Australia has experienced a declining trend in annual rainfall and gradual warming over the last 30 years. The distribution of rainfall has also changed, with lower autumn rainfall, patchy breaks to the season, and shorter springs. This has important implications for the productivity of legume pastures in the region, which is dominated by annual species, particularly subterranean clover (Trifolium subterraneum L.), annual medics (Medicago spp.), serradella (Ornithopus spp.), and biserrula (Biserrula pelecinus L.). For annual pasture legumes, appropriate patterns of seed softening and germination behaviour, efficiency of phosphorus and potassium uptake, responses to elevated levels of atmospheric CO2, and drought resistance of seedlings and mature plants will assume increasing importance. While these traits can be targeted in pasture breeding programs, it will also be important to exploit farming system opportunities to optimise the annual legume component of the feed base. These opportunities may take the form of incorporating strategic shrub reserves and grazing crops to allow for pasture deferment in autumn–winter. Perennial forages may become more important in this context, as discussed in terms of the development of the perennial legume tedera (Bituminaria bituminosa var. albomarginata C.H. Stirton).


1957 ◽  
Vol 8 (1) ◽  
pp. 1 ◽  
Author(s):  
JN Black

Three strains of subterranean clover (Bacchus Marsh, Clare, and Mount Barker) were grown in pot culture at the Waite Agricultural Research Institute; for each strain, seed of four widely separated sizes mere sown. Dry weight a t any one time in the early vegetative stage was linearly related to embryo weight, but was independent of strain. Hence differences in early growth noted under uniform environmental conditions between strains are the result not of differing relative growth rates, but of differences in the size distribution within the seed populations; evidence is presented suggesting that there may well be little difference in the size distribution of seed of Bacchus Marsh and Mt. Barker, but that Clare contains a higher proportion of large seed, and thus as a strain would be expected to give greater early production. Leaf area per plant was also linearly related to embryo weight but independent of strain; but for a common embryo weight, Clare was found to have fewer leaves than the other two strains. Examination of the areas of successive leaves showed that the maintenance of similar total leaf areas depended on a balance of rate of leaf production and size of individual leaves; in relation to Bacchus Marsh and Mt. Barker, Clare has fewer but large1 leaves.


1985 ◽  
Vol 25 (4) ◽  
pp. 850 ◽  
Author(s):  
MJ Barbetti

The effects of inoculum level, and temperature and humidity regimes on the development of Cercospora blackstem disease (caused by Cercospora zebrina) in subterranean clover (Trifolium subterraneum) were investigated. Mycelial fragments were an effective and reliable inoculum. The incidence, severity, and the rate of disease development increased with increasing period of high humidity after inoculation and with increasing concentrations of inoculum. Disease was greatest at 18/13� (12/12 h, day/ night), followed by 21/16�C, and then l5/10�C While all cultivars of T. subterraneum sprayed with hyphal fragments of C. zebrina became infected, Trikkala and Larisa showed some resistance. Of the alternative pasture legumes, lucerne (Medicago sativa), medic (M. littoralis, M. truncatula), drooping-flowered clover (T. cernuum), strawberry clover (T. fragiferum), rose clover (T. hirtum) and white clover (T. repens) were all susceptible; only serradella (Ornithopus compressus) was resistant.


1955 ◽  
Vol 6 (2) ◽  
pp. 211 ◽  
Author(s):  
Y Aitken

The value of the annual legume Trifolium subterraneum L. (subterranean clover) in Australian agriculture warrants more precise knowledge of factors affecting flowering and prolific seeding. The effect of temperature and photoperiod on flower initiation in early and later flowering varieties has been investigated in an effort to determine the geographical limits of the use of subterranean clover in Australia. At any time of sowing, the length of the growing season of a variety depends greatly on the variety's response to the temperature level and to the photoperiod of the first few weeks after germination. In all varieties of subterranean clover so far examined flower initiation is accelerated by a period of low temperature. In the later varieties, flower initiation is prevented by an insufficient period of low temperature. The length of the necessary cold period is shortened under longer photoperiod. Early varieties are early flowering because they do not require so long a cold period or so low a temperature as late varieties.


2001 ◽  
Vol 52 (3) ◽  
pp. 367 ◽  
Author(s):  
R. Chapman ◽  
S. Asseng

Historical meteorological data were used to estimate the frequency and timing of false break events at 10 locations in the annual pasture and wheat producing area in the Mediterranean climatic region of Western Australia. The seasonal pattern of false breaks identified by this analysis was compared with the dynamics of dormancy release in a field population of subterranean clover (Trifolium subterraneum L.) to determine the influence that these events may have on the legume content of annual pasture communities in this region. False break events were estimated to occur on approximately 2 of every 3 years (611–72% of years) with no significant differences across the area investigated. Changes in the risk of false break events were examined over discrete time periods. The period of greatest risk was predicted to occur during early autumn (early March to mid April). Seed softening is virtually complete in subterranean clover at this point. The seed bank strategy of this species is, therefore, not well adapted to withstand the effects of false breaks. This might largely explain the poor persistence of subterranean clover in the annual pasture communities in the Mediterranean region of Western Australia. The legume content of these pastures might be improved by selecting species with late dormancy release strategies that will give better protection from false breaks.


2001 ◽  
Vol 41 (2) ◽  
pp. 169 ◽  
Author(s):  
Y. J. Ru ◽  
J. A. Fortune

The nutritive value of 26 cultivars of dry, mature subterranean clover was evaluated at Shenton Park, Perth, Western Australia. The cultivars were divided into 3 maturity groups according to flowering time and each cultivar was sown in blocks comprising 4 replicates. The plots were grazed by sheep at 2-week intervals during the growing season. Dry mature plant material and soil were sampled in summer to examine the effect of grazing and cultivar on seed yield and nutritive value of feed residues. Cultivars heavily grazed in spring had a low herbage mass. There was no difference in seed yield and seed weight between heavily and lightly grazed cultivars. Dry matter digestibility and mineral content of dry residues was inconsistent for the 2 grazing treatments. The dry matter digestibility of dry, mature subterranean clover ranged from 40 to 56%, with a wide range of crude fibre, nitrogen and mineral content for the 26 cultivars. While most minerals in the dry residues were above the requirement for sheep, 7 cultivars had a zinc content less than the maintenance requirement for sheep. There was an imbalance for all cultivars in calcium: phosphorus with a range of 4–10: 1. Concurrent estimates on the yield and composition of seed indicated that seed can be resource of minerals for grazing animals in summer. Most cultivars had a seed yield over 100 g/m2 with that of 9 cultivars being over 130 g/m2. Seed was rich in nitrogen, sodium, phosphorus, potassium, magnesium, zinc and copper, and poor in sodium, calcium and manganese. However, there were no cultivars with an appropriate ratio of calcium and phosphorus. The imbalance in nitrogen and sulfur was a result of high nitrogen content with the ratio ranging from 19: 1 to 29: 1.


2003 ◽  
Vol 43 (10) ◽  
pp. 1221 ◽  
Author(s):  
M. D. A. Bolland ◽  
J. S. Yeates ◽  
M. F. Clarke

The dry herbage yield increase (response) of subterranean clover (Trifolium subterraneum L.)-based pasture (>85% clover) to applications of different sources of sulfur (S) was compared in 7 field experiments on very sandy soils in the > 650 mm annual average rainfall areas of south-western Australia where S deficiency of clover is common when pastures grow rapidly during spring (August–November). The sources compared were single superphosphate, finely grained and coarsely grained gypsum from deposits in south-western Australia, and elemental S. All sources were broadcast (topdressed) once only onto each plot, 3 weeks after pasture emerged at the start of the first growing season. In each subsequent year, fresh fertiliser-S as single superphosphate was applied 3 weeks after pasture emerged to nil-S plots previously not treated with S since the start of the experiment. This was to determine the residual value of sources applied at the start of the experiment in each subsequent year relative to superphosphate freshly-applied in each subsequent year. In addition, superphosphate was also applied 6, 12 and 16 weeks after emergence of pasture in each year, using nil-S plots not previously treated with S since the start of the experiment. Pasture responses to applied S are usually larger after mid-August, so applying S later may match plant demand increasing the effectiveness of S for pasture production and may also reduce leaching losses of the applied S.At the same site, yield increases to applied S varied greatly, from 0 to 300%, at different harvests in the same or different years. These variations in yield responses to applied S are attributed to the net effect of mineralisation of different amounts of S from soil organic matter, dissolution of S from fertilisers, and different amounts of leaching losses of S from soil by rainfall. Within each year at each site, yield increases were mostly larger in spring (September–November) than in autumn (June–August). In the year of application, single superphosphate was equally or more effective than the other sources. In years when large responses to S occurred, applying single superphosphate later in the year was more effective than applying single superphosphate 3 weeks after pasture emerged (standard practice), so within each year the most recently applied single superphosphate treatment was the most effective S source. All sources generally had negligible residual value, so S needed to be applied each year to ensure S deficiency did not reduce pasture production.


2001 ◽  
Vol 41 (2) ◽  
pp. 187 ◽  
Author(s):  
R. Aldaoud ◽  
W. Guppy ◽  
L. Callinan ◽  
S. F. Flett ◽  
K. A. Wratten ◽  
...  

In 1995–96, a survey of soil samples from subterranean clover (Trifolium subterraneum L.) paddocks was conducted across Victoria, South Australia, New South Wales and Western Australia, to determine the distribution and the prevalence of races of Phytophthora clandestina (as determined by the development of root rot on differential cultivars), and the association of its occurrence with paddock variables. In all states, there was a weak but significant association between P. clandestina detected in soil samples and subsequent root rot susceptibility of differential cultivars grown in these soil samples. Phytophthora clandestina was found in 38% of the sampled sites, with a significantly lower prevalence in South Australia (27%). There were significant positive associations between P. clandestina detection and increased soil salinity (Western Australia), early growth stages of subterranean clover (Victoria), mature subterranean clover (South Australia), recently sown subterranean clover (South Australia), paddocks with higher subterranean clover content (Victoria), where herbicides were not applied (South Australia), irrigation (New South Wales and Victoria), cattle grazing (South Australia and Victoria), early sampling dates (Victoria and New South Wales), sampling shortly after the autumn break or first irrigation (Victoria), shorter soil storage time (Victoria) and farmer’s perception of root rot being present (Victoria and New South Wales). Only 29% of P. clandestina isolates could be classified under the 5 known races. Some of the unknown races were virulent on cv. Seaton Park LF (most resistant) and others were avirulent on cv. Woogenellup (most susceptible). Race 1 was significantly less prevalent in South Australia than Victoria and race 0 was significantly less prevalent in New South Wales than in South Australia and Western Australia. This study revealed extremely wide variation in the virulence of P. clandestina. The potential importance of the results on programs to breed for resistance to root rot are discussed. in South Australia.


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