Time distribution of seedlings emergence from single seed crops of several annual pasture legumes

1972 ◽  
Vol 12 (59) ◽  
pp. 628 ◽  
Author(s):  
GB Taylor
Keyword(s):  
Seed Set ◽  
Seedling Emergence ◽  
Subterranean Clover ◽  
Hard Seed ◽  
Barrel Medic ◽  
The Third ◽  
Single Seed ◽  
Pasture Legumes ◽  
Original Seed ◽  
Seed Crops

Seedling emergence from single seed crops of Dwalganup and Geraldton subterranean clover, Yamina cupped clover, Troodos and Kondinin rose clover, and Cyprus barrel medic, was studied in a low rainfall wheatbelt environment in Western Australia. The proportion of the original seed set recovered as seedlings was highest from the subterranean clovers in the first year but about the same for all genotypes in the second year. Few subterranean clover seeds were recovered in the third regeneration year either as seedlings or residual hard seeds, whereas significant proportions of the original seed of the other genotypes were obtained. More than 10 per cent of the original seed of Cyprus barrel medic and Yamina cupped clover remained ungerminated at the end of the third season. Between about 35 and 75 per cent of the original seed set was not accounted for in the genotypes studied. The proportions of the total seedling numbers that emerged following summer and early autumn rains were generally highest from the subterranean clovers and least from the cupped clover and medic. It is suggested that these different patterns of emergence within years were the result of differences in embyro dormancy rather than different patterns of hard seed breakdown.

Long term patterns of seed softening and seedling establishment from single seed crops of subterranean clover

1984 ◽  
Vol 24 (125) ◽  
pp. 200 ◽  
Author(s):  
GB Taylor ◽  
RC Rossiter ◽  
MJ Palmer
Keyword(s):  
Seedling Establishment ◽  
Subterranean Clover ◽  
Late Summer ◽  
Trifolium Subterraneum ◽  
The Other ◽  
Hard Seed ◽  
Single Seed ◽  
One Year ◽  
Seed Crops

Single seed crops of eight varieties of subterranean clover (Trifolium subterraneum) were grown in swards in four successive years in a medium rainfall environment at Bakers Hill, Western Australia. Measurements were made of seed production, the progress of seed softening within the first two summers, and residual hard seed and seedling numbers after the break of season for up to six successive regeneration years. Patterns of seed softening were also measured in a laboratory oven with a diurnal temperature fluctuation of 60/15�C. Approximately half the seeds of all varieties softened over the first summer and generally well over half the residual seeds softened during the second summer. Up to 18% of seeds of the hardest seeded variety, Northam, and 11% of Geraldton seeds persisted to the end of the third summer as hard seeds. Seed softening patterns showed a significant variety x regeneration year interaction due mainly to a slower rate of softening of Northam seeds relative to the other varieties after the first summer. In six of the varieties, seeds generally softened more slowly in the laboratory than in the field but in the case of the other two varieties this trend was reversed. Nevertheless, ranking of varieties for rate of seed softening was similar in field and laboratory. Seedling establishment ranged from 28 to 100% of soft seeds, depending on the incidence of late summer and autumn rains. It appeared that all varieties in the study would regenerate satisfactorily at densities of more than 15 plants/dm2 after at least one year in which little or no seed is set. Slower rates of softening would probably be desirable in drier regions or in rotation systems involving cropping.

Seed softening patterns from single seed crops of subterranean clover (Trifolium subterraneum L.) in a cool temperate environment

1995 ◽  
Vol 35 (8) ◽  
pp. 1117 ◽  
Author(s):  
PM Evans ◽  
EJ Hall
Keyword(s):  
Seed Set ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
First Year ◽  
Original Seed ◽  
Cool Temperate ◽  
Set Up ◽  
Negative Exponential ◽  
Seed Crops ◽  
The Relationship

An experiment was set up in northern Tasmania with 7 cultivars of subterranean clover widely ranging in maturity and levels of hardseededness. They were planted as pure swards and in a mixture with perennial ryegrass. After seed set in the first year, all seedling regenerations were counted and then killed, and seed populations were measured each summer for 6 years. No significant differences in seed losses existed between the pure swards and the mixtures or between cultivars. Negative exponential functions of the relationship between seed banks and time fitted the data well with r2 ranging from 0.87 (Nungarin) to 0.998 (Trikkala). By mid-summer of the sixth year the percentages of the original seed left in the ground were: Enfield 12%, Woogenellup 19%, Trikkala 20%, Nungarin 21%, Larisa 24%, and Karridale and Mt Barker 31%. Seeds at higher latitudes were lost at about half the rates experienced at lower latitudes with drier, hotter summers. The higher percentages of seed remaining in plots with later maturing cultivars suggest that environmental conditions favoured the production of hard seeds while the reverse was the case with very early, hardseeded cultivars like Nungarin.

Application of non-selective herbicides during flowering of pasture legumes can reduce seed yield and alter seed characteristics

1998 ◽  
Vol 38 (6) ◽  
pp. 583 ◽  
Author(s):  
A. Wallace ◽  
R. A. Lancaster ◽  
N. L. Hill
Keyword(s):  
Seed Yield ◽  
Seed Set ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Farming Systems ◽  
Early Summer ◽  
Hard Seed ◽  
Time Of Application ◽  
Pasture Legumes ◽  
Clover Seed

Summary. Spraytopping, the application of a low rate of non-selective herbicide (usually glyphosate or paraquat) to annual grass seed heads in the spring or early summer for seed set control is widely practised throughout Australia. While grasses are the targets of the spray treatment, annual pasture legumes may also be damaged by spraytopping, particularly if the legumes are flowering at the time of application. The effect of applying glyphosate (90, 112 or 162 g a.i./ha), paraquat (100 g a.i./ha) and glyphosate plus MCPA (90 + 150 g a.i./ha) to subterranean clover (Trifolium subterraneum L. cv. Dalkeith) and annual medic (Medicago polymorpha L. cvv. Serena, Santiago and Circle Valley) pastures at various times during flowering was investigated during the spring of 1993 and 1994. Experiments were located at Tincurrin and Tenindewa, Western Australia. Subterranean clover seed yield was most affected by applications of glyphosate (90 and 162 g a.i./ha) and glyphosate plus MCPA (90 + 150 g a.i./ha) during early–mid flowering. Seed yield was reduced by as much as 88% following application of glyphosate plus MCPA when 20% of the subterranean clover plants were flowering. Treatment with paraquat (100 g a.i./ha) during mid–late flowering reduced seed yield of subterranean clover by 25–50% in experiment 1 only. Medic seed yield was reduced up to 90% depending on cultivar when glyphosate (112 g a.i./ha) was applied during early–mid flowering. In addition to seed yield, the level of hard seed was assessed. Treatment of subterranean clover during early–mid flowering with glyphosate (90 and 162 g a.i./ha) significantly reduced the quantity of hard seed produced. Thirty–forty percent of subterranean clover seed was germinable soon after seed set, compared with 7–17% germinable for the seed from untreated plants. Treatment with glyphosate (112 g a.i./ha) reduced the proportion of hard seed in the medics when applied during mid flowering. Treatment with paraquat had little effect on the proportion of hard seed formed. This work demonstrates that using a spraytopping technique for control of seed set in annual grasses may dramatically reduce seed yield in pasture legumes. Spraytopping can further reduce the ability of legumes to persist in cropping rotations by reducing the amount of hard seed formed. Implications for practical farming systems are outlined.

Hardseededness and pattern of hard seed breakdown in Sardinian populations of Medicago polymorpha under field conditions

1996 ◽  
Vol 126 (2) ◽  
pp. 161-168 ◽  
Author(s):  
C. Porqueddu ◽  
A. Loi ◽  
P. S. Cocks
Keyword(s):  
Mediterranean Basin ◽  
Seedling Emergence ◽  
Experimental Period ◽  
First Year ◽  
Medicago Polymorpha ◽  
Hard Seed ◽  
Pasture Legumes ◽  
Commercial Cultivars ◽  
Previous Summer ◽  
The Mediterranean Basin

SUMMARYThe hardseededness and pattern of hard seed breakdown of 35 accessions of Medicago polymorpha, collected in Sardinia, were compared with Circle Valley, an Australian cultivar, near Sassari, northern Sardinia. The seed was produced in three consecutive years (1991–93), and the hardseededness measured at intervals in trie field during the summer following its production. The results were related to previously measured pod characteristics that separated the varieties polymorpha and vulgarisThe variety polymorpha, which had been collected mainly from coastal regions, was harder seeded than the variety vulgaris, which had been collected mainly from cooler, inland regions. Wherever the origin, hardseededness levels remained > 85% even in the year when seed softening was greatest (1992). In other years means of 94% (1991) and 97% (1993) of seed remained hard in late September. In 1992 and 1993 most hard seed breakdown occurred between early August and early September, while in 1991 hard seed breakdown occurred in September itself. There was little difference between varieties in the pattern of hard seed breakdown. Seedling emergence was related to the amount of seed that became soft during the previous summer. The results also confirmed that hard seeds soften sequentially from the proximal end of the pod (nearest the calyx) to the distal end.The Australian cultivar was one of the hardest seeded accessions, showing very little hard seed breakdown during the experimental period. This result highlights the importance of selecting pasture legumes under the conditions in which they are to be used: in Australia, cultivar Circle Valley usually loses some 20% of its hardseededness in the first year, comparable with the softest Sardinian accessions in Sardinia. Even among the Sardinian accessions, most were probably too hard seeded in 1993. Nevertheless it is likely that material in this experiment will be released as commercial cultivars for Sardinia and other similar environments in the Mediterranean basin.

Genotype × site interactions in seed production, hard seed breakdown and regeneration of annual medics (Medicago spp.) in west Asia

1995 ◽  
Vol 125 (2) ◽  
pp. 199-209 ◽  
Author(s):  
P. S. Cocks
Keyword(s):  
Seed Production ◽  
Principal Component ◽  
First Year ◽  
Hard Seed ◽  
The Third ◽  
Pasture Legumes ◽  
Wheat Pasture ◽  
The Mean ◽  
Annual Medics ◽  
Pasture Plants

SUMMARYSeed production of annual medics was measured at four sites in Syria and Jordan between 1986/87 and 1988/89. Plots sown to medic in the first year were sown to wheat in the second year, and medic regeneration was measured in the third year. At three of the sites, adjacent plots were established in the second and third years and herbage production, and regeneration where appropriate, were measured in the third year. In this way, genotype × site interactions were used to assess medic adaptation to wheat/pasture rotations, continuous pasture and newly sown pasture.Seed production was correlated with rainfall, the mean yield of 14 genotypes ranging from zero at 160 mm to 1 tonne/ha at 510 mm. Medicago polymorpha produced the highest yields, though not at the lowest rainfalls. Yields of M. rotata were also above average. There was, however, wide variation between species in seed weight, pod weight and seeds/pod.Regeneration was better after wheat than after pasture. Herbage production was slightly better after pasture than after wheat, and both were greatly superior to that of newly sown pasture. After 2 years' germination, most genotypes retained more than half (mean 60%) and up to 99% of the seed produced in the first year.Genotype × environment interactions were tested using analysis of variance (ANOVA), regression (Finlay & Wilkinson 1963) and principal component analysis (PCA). Because adaptation in pasture plants depends on many variables, PCA proved to be the most useful technique and the simplest to apply. ANOVA and regression were limited by their inability to process more than one variable at a time. Regression analysis is further limited by requiring a greater number of sites.Based on seed production, seed survival, seedling regeneration and herbage production, certain locally collected genotypes of M. rigidula, M. noeana, M. polymorpha and possibly M. rotala, were adapted to conditions in Syria and Jordan. A similar methodology could be used to test pasture legumes throughout west Asia and north Africa

Sulfur nutrition of temperate pasture species. II. A comparison of subterranean clover cultivars, medics and grasses

1984 ◽  
Vol 35 (3) ◽  
pp. 389 ◽  
Author(s):  
MA Gilbert ◽  
AD Robson
Keyword(s):  
Maximum Yield ◽  
Subterranean Clover ◽  
Nitrogen Supply ◽  
Sulfur Deficiency ◽  
Barrel Medic ◽  
Pasture Legumes ◽  
Sulfur Supply ◽  
Wimmera Ryegrass ◽  
Brome Grass ◽  
Sulfur Nutrition

The external and internal requirements for sulfur of five pasture legumes and three grasses of temperate origin were examined in a pot experiment in which plants were grown with seven levels of sulfur supply for 58 days. Nitrogen supply was non-limiting. There was no distinct difference between legumes and grasses in their external requirement for sulfur (i.e. the amount of sulfur required for 90% of maximum yield) or in their sensitivity to sulfur deficiency (i.e. yield at the lowest sulfur supply expressed as a percentage of maximum yield). The requirement for sulfur (mg/pot) fell in the following order: Hunter River lucerne (24) > Jemalong barrel medic (19) > brome grass and Wimmera ryegrass (18) > barley grass (15) > Clare subterranean clover (13) > Trikkala subterranean clover (11) > Seaton Park subterranean clover (10). The high external requirement for sulfur of Hunter River lucerne appears to be due to its poor ability to distribute sulfur from root to shoot and to its high internal requirement for sulfur. However, for Jemalong barrel medic, the high external requirement was solely due to its high internal requirement for sulfur. The higher external requirement for sulfur of the grasses compared with the subterranean clover cultivars appears to be due to the poorer ability of the grasses to obtain sulfur from the soil used in this experiment, rather than to differences in the transfer of sulfur from root to shoot, or in their internal requirement for sulfur.

Comparison of the performance of subterranean clover cultivars in southern New South Wales. 1. Persistence, productivity, and seed yields

1993 ◽  
Vol 33 (5) ◽  
pp. 581 ◽  
Author(s):  
BS Dear ◽  
PD Cregan ◽  
GM Murray
Keyword(s):  
Seed Set ◽  
Plant Density ◽  
New South ◽  
New South Wales ◽  
Subterranean Clover ◽  
Wagga Wagga ◽  
Hard Seed ◽  
South Wales ◽  
Seed Reserves ◽  
Seed Yields

The density, productivity, flowering characteristics, and seed reserves of 14 lines (10 cultivars and 4 experimental lines) of subterranean clover were observed over 5 years (1983-87) on a red earth soil at Wagga Wagga, New South Wales. Plant density increased from 149-318 plants/m2 in 1983 to 1975-13925 plants/m'n 1987. Herbage yields of all cultivars during autumn-winter were similar in most years except in July 1985 when Seaton Park was superior. Cultivars in the midseason or later flowering groups were more productive in late spring and better able to utilise the extended growing seasons that occur periodically in this environment. The mean time from emergence to 5% flowering of all cultivars was 168 days with March germination in 1985 but decreased to 13.5 days with May germination in 1986. The number of days to flowering at Wagga Wagga was highly correlated with maturity ranking at Perth (r2 = 0.92 in 1985 and? = 0.93 in 1986). In the first year, average seed set was 295 kg seed/ha. but by summer of the fourth year the seed pool ranged from 124 kg/ha for Clare to 1190 kg/ha for Nungarin, the earliest flowering cultivar. The quantity of hard seed that carried over to the next year varied significantly between cultivars, with Enfield, Woogenellup, and Clare having the least, and Nungarin, Northam, Dalkeith, and Daliak the most. Seed set was related to maturity ranking only in 1984, although root disease probably affected seed yields in 1985-86. The proportion of hard seed that carried over was much higher than expected, particularly in soft-seeded cultivars. The newly released cultivar Junee was well adapted to the environment; it was later maturing than the recommended cultivar Seaton Park but was able to maintain high seed reserves. Karridale, another new cultivar, maintained higher seed reserves than the older Mount Barker.

Flower initiation in pasture legumes. III. Flower initiation in Medicago tribuloides Desr. and other annual medics.

1955 ◽  
Vol 6 (2) ◽  
pp. 258 ◽  
Author(s):  
Y Aitken
Keyword(s):  
Low Temperature ◽  
Subterranean Clover ◽  
Late Summer ◽  
Flower Initiation ◽  
Commercial Variety ◽  
Barrel Medic ◽  
Pasture Legumes ◽  
Annual Medics ◽  
Long Photoperiod

Observations on barrel medic (Medicago tribuloides Desr., commercial variety) sown throughout the year in the field showed that the flower initiation of the winter sowings was the most rapid and that of the late summer sowings the most delayed. This delay was due to the absence of sufficiently low temperature following germination. Low temperature and long photoperiod accelerate flower initiation in barrel medic as in subterranean clover. Five types of annual medic that persist under Mallee conditions are similar in their flower initiation character to that of the "second-early" varieties of subterranean clover.

Responses of pasture legumes to zinc on calcareous soils in the Riverina, New South Wales

1962 ◽  
Vol 2 (7) ◽  
pp. 228 ◽  
Author(s):  
CR Kleinig ◽  
J Loveday
Keyword(s):  
White Clover ◽  
Surface Soil ◽  
New South ◽  
New South Wales ◽  
Calcareous Soils ◽  
Subterranean Clover ◽  
Barrel Medic ◽  
Pasture Legumes ◽  
South Wales ◽  
Better Than

The low availability of zinc on a number of calcareous grey and brown soils of heavy texture with pH>8, in the Coleambally Irrigation and Balranald areas of New South Wales, resulted in marked deficient symptoms in, and responses to zinc by, Bacchus Marsh subterranean clover (Trifolium subterranean L.), grown on these soils. An interaction between zinc and manganese occurred but there was no yield advantage in applying manganese in place of, or together with, zinc. Healthy subterranean clover grew on the surface soil (0-4 in.) of Yooroobla clay, a gilgai puff, but plants on the subsoil, which is exposed when the soil is leveled for irrigation, were extremely, zinc deficient. The pH of the subsoil is generally about 0.5 units higher than that of the surface soil. Legume species and strains differed in their response to zinc. Ladino white clover (Trifolium repens L.) and Clare subterranean clover responded less to applied zinc than Bacchus Marsh subterranean clover, and barrel medic 173 (Medicago tribuloides Desr.) responded less than Ladino white clover. When no zinc was applied barrel medic 173 yielded better than Ladino white clover, and Ladino white clover and Clare subterranean clover better than Bacchus Marsh subterranean clover.

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
Keyword(s):  
Western Australia ◽  
Large Scale ◽  
Agricultural Research ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Barrel Medic ◽  
Pasture Legumes ◽  
Waite Agricultural Research Institute ◽  
Wide Range ◽  
Seed Increase

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.

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