Short-term patterns of seed softening in Trifolium subterraneum, T. glomeratum and Medicago polymorpha

1996 ◽  
Vol 47 (5) ◽  
pp. 775 ◽  
Author(s):  
FP Smith ◽  
PS Cocks ◽  
MA Ewing
Keyword(s):  
Selection Criterion ◽  
Trifolium Subterraneum ◽  
First Year ◽  
Stage Model ◽  
Mediterranean Environment ◽  
Short Term ◽  
Medicago Polymorpha ◽  
Pasture Legumes ◽  
Hard Seeds ◽  
Selection Of

The short-term (within-year) dynamics of the softening of hard seeds in a number of accessions of Trifolium subterraneum L., T. glomeratum L., and Medicago polymorpha L. were monitored in the field. There were distinct differences in the patterns of seed softening between and within species and between years. Seed softening was accurately described by logistic curves with calculated half-lives of hard seeds (within a given year) a good indicator of differences in the softening patterns between species and accessions. T. subterraneum cv. Nungarin softened most rapidly over summer, ceasing by March (half-life in the first year 45 days), whereas M. polymorpha cv. Serena and 2 accessions of T. glomeratum softened mainly during the autumn (half-lives of 126, 104, and 136 days, respectively) First year half-lives of 4 other accessions of T. subterraneum ranged from 64 to 79 days. The results showed that large seeds were more likely to soften in the first year than were small seeds. The different patterns can be explained using Taylor's 2-stage model of seed softening. The implications of different patterns are discussed in terms of adaptation to a Mediterranean environment. T. glomeratum and M. polymorpha cv. Serena are considered to have a short-term pattern of seed softening well adapted to an environment where false breaks to the growing season are likely. The pattern of T. subterraneum is considered to be less well adapted to such an environment. However, variation within the species indicates the potential for selection of better adapted varieties. The inclusion of the short-term seed softening pattern as a selection criterion for pasture legumes is recommended.

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.

The short-term effects of rock phosphate and super-phosphate on a subterranean clover pasture.

1955 ◽  
Vol 6 (4) ◽  
pp. 553 ◽  
Author(s):  
RC Rossiter ◽  
PG Ozanne
Keyword(s):  
Rock Phosphate ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Phosphorus Recovery ◽  
Available Phosphorus ◽  
First Year ◽  
Short Term ◽  
Pasture Production ◽  
Total Plant ◽  
Second Year

A 2-year field experiment is described, in which an annual-type pasture was grown on a soil of lateritic origin with various initial rates of rock phosphate and superphosphate. The soil was acutely deficient in plant-available phosphorus at the outset. Application of superphosphate led to the expected increases in total pasture production, but rock phosphate also gave substantial yield increases, even during the first season. Differential species effects were noted; subterranean clover (Trifolium subterraneum L.) and cape-weed (Cryptostemma calendula Druce) responded about equally to superphosphate, but the clover responded to rock phosphate to a greater extent than did cape-weed. Both relative efficiency for total plant growth and percentage utilization of applied phosphorus were much higher with the soluble phosphatic fertilizer than with rock phosphate, especially in the first year. However, phosphorus recovery from rock phosphate was as high in the second year as in the first, whereas there was a marked decrease in the second year from superphosphate.

scholarly journals First year seed softening in three Hedysarum spp. in southern Queensland

2003 ◽  
Vol 43 (11) ◽  
pp. 1303 ◽  
Author(s):  
L. W. Bell ◽  
D. L. Lloyd ◽  
K. L. Bell ◽  
B. Johnson ◽  
K. C. Teasdale
Keyword(s):  
Soil Surface ◽  
First Year ◽  
Hard Seed ◽  
Seed Content ◽  
Constant Rate ◽  
Significant Difference ◽  
Hard Seeds ◽  
Hedysarum Coronarium ◽  
Seed Characteristics ◽  
Selection Of

Seed softening was investigated in 41 lines of Hedysarum coronarium, 5 lines of H. carnosum and 8�lines of H. flexuosum grown at Oakey, Queensland in 2000. After testing for initial hard seed content in each line, the remaining hard seeds were placed on the soil surface at Kingsthorpe on 15 January 2001. Changes in hard seed levels over the ensuing summer-autumn seed softening period were measured. The initial hard seed content in each species ranged from 20 to 79% in H. coronarium; 31 to 79% in H. carnosum; and 54 to 83% in H. flexuosum. No significant difference in the time of seed softening between accessions or species was identified. Despite the similar timing, the extent of softening varied greatly between accessions and species. The proportion of initially hard seed that softened ranged from 54 to 95% in H. coronarium; 27 to 45% in H. carnosum; and 50 to 74% in H. flexuosum. Accessions of H. coronarium and H. flexuosum softened the greatest proportion of seed between 15 January and 22�February with reducing amounts thereafter. Accessions of H. carnosum softened less seed over this period, appearing to display a slower, more constant rate of softening. Although total hard seed levels were relatively low, there was sufficient variability in hard seed levels to provide some scope for selection of desired hard seed characteristics.

Incidence and measurement of autumn seed softening within Medicago polymorpha L

1996 ◽  
Vol 47 (4) ◽  
pp. 575 ◽  
Author(s):  
GB Taylor
Keyword(s):  
Soil Surface ◽  
Temperature Fluctuations ◽  
The Other ◽  
Laboratory Simulation ◽  
First Year ◽  
Medicago Polymorpha ◽  
Softening Behaviour ◽  
Hard Seeds ◽  
Total Seed

Softening of hard seeds during autumn rather than summer is a desirable characteristic for reducing seed losses in annual legumes from false breaks of season in Mediterranean environments. The incidence of this characteristic in Medicago polymorpha L. was determined in 34 lines grown at Toodyay, Western Australia, in 1993 and collected in December. Patterns of seed softening during summer and autumn 1993-94 were studied in pods placed on the soil surface in the field at Merredin, and in laboratory and glasshouse simulations at Perth. Summer seed softening was simulated in the laboratory by the removal of seeds from pods by hand, subjecting them to a diurnally fluctuating temperature of 60/15�C for 16 weeks, and testing their permeability. Residual hard seeds were subjected to 4 gradual diurnal temperature fluctuations of 35/10�C and re-tested for permeability as a measure of autumn seed softening. In the glasshouse study, pods were placed on the surface of soil in boxes, and emerged seedlings were counted after watering in March and June. Field softening in the first year ranged from 6.8 to 69.6%, but exceeded 40% in only 6 of the 34 lines. Proportions of total soft seeds present in the field in June that had softened after 1 March in the 34 lines were normally distributed, and ranged from 2.5 to 78.7%. The laboratory simulation markedly underestimated both autumn and total seed softening in 13 of the lines but effectively predicted field softening behaviour in the other 21 lines. The glasshouse technique overestimated the proportions of seeds softening in autumn in most lines and underestimated total softening in 12 of the 34 lines. A technique involving the use of a rain-out shelter is proposed for routine determination of the incidence of autumn seed softening in medic evaluation programs.

Long-term patterns of seed softening in some annual pasture legumes in a low rainfall environment

1992 ◽  
Vol 32 (3) ◽  
pp. 331 ◽  
Author(s):  
GB Taylor ◽  
MA Ewing
Keyword(s):  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Medicago Polymorpha ◽  
Pasture Legumes ◽  
Burr Medic ◽  
Growing Environment ◽  
Simulated Field ◽  
Favourable Environment

Annual rates of seed softening were determined from 4 lines of burr medic (Medicago polymorpha), 1 barrel medic (M. truncatula), and 1 subterranean clover (Trifolium subterraneum) grown at Merredin in the 1 year. Measurements were also made on one of the lines of burr medic grown in 2 other environments, Gnowangerup and Eneabba, in the same year. Burrs were placed on the soil surface at Merredin and the numbers of residual hard seeds determined each year for up to 5 years in this one environment. Patterns of softening of seeds from the same seed populations were also determined in a laboratory oven with a diurnal temperature fluctuation of 60/15�C. In the field, the softening rates of the 5 medics grown at Merredin were similar, averaging 21% of the original seeds each year for the first 4 years. Seeds of the burr medic grown in a more favourable environment at Eneabba were much slower to soften (averaging 14%); hence, hardseededness in these medics was influenced more by the growing environment than by genotype. More than half of the seeds of subterranean clover softened in the field over the first summer, with declining annual proportions thereafter. There were clear differences between the clover and medics in both pattern and rate of seed softening. The lower seed-softening rate of medics than of subterranean clover was more favourable for ley systems involving frequent cropping, especially in low rainfall areas. Treatment of seeds at 60/15�C simulated field softening for subterranean clover well but produced misleading results for the medics.

scholarly journals Legume Ecotypes and Commercial Cultivars Differ in Performance and Potential Suitability for Use as Permanent Living Mulch in Mediterranean Vegetable Systems

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1836
Author(s):  
Federico Leoni ◽  
Mariateresa Lazzaro ◽  
Stefano Carlesi ◽  
Anna-Camilla Moonen
Keyword(s):  
Weed Control ◽  
Growth Traits ◽  
Plant Competition ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Weed Suppression ◽  
Medicago Polymorpha ◽  
Commercial Cultivars ◽  
Promising Solution ◽  
Selection Of

Weed control in organic conservative vegetable systems is extremely challenging and the use of legume permanent living mulches (pLM) presents an interesting opportunity. The successful use of pLM is largely determined by the choice of appropriate legumes which are able to combine adequate weed control with a marginal competitive effect on the cash crop(s). However, the availability of legumes for such systems is limited and their characterization based on growth traits can support the selection of suitable legumes for conservation organic vegetable systems. The current study investigated weed control capacity and variability in morphological and phenological traits relevant in inter-plant competition among a range of 11 commercial cultivars of legumes and seven ecotypes of Medicago polymorpha (bur medic). For commercial cultivars, Lotus corniculatus (bird’s-foot trefoil) and Trifolium repens (white clover) showed the best weed control capacity, while Trifolium subterraneum (subterranean clover) and Medicago polymopha had more suitable characteristics for a rapid and complete establishment of the pLM. Overall, legume mulches appear more effective in dicotyledonous than in monocotyledonous weed control. Trifolium subterraneum cv. Antas and T. repens cv. Haifa were identified as the potentially most suitable legumes for use as pLM and their use in mixtures could be a promising solution. In addition, the ecotypes of Medicago polymorpha Manciano and Talamone proved to be well adapted for local environmental conditions and they showed a better weed suppression than the commercial cultivars of Medicago polymorpha.

scholarly journals Early selection of elite plants in Asparagus

Bragantia ◽  
2000 ◽  
Vol 59 (1) ◽  
pp. 21-26 ◽  
Author(s):  
ENRIQUE LUIS COINTRY ◽  
FERNANDO SEBASTIÁN LÓPEZ ANIDO ◽  
ILEANA GATTI ◽  
VANINA PAMELA CRAVERO ◽  
INÉS TERESA FIRPO ◽  
...  
Keyword(s):  
Yield Components ◽  
Total Yield ◽  
Selection Criterion ◽  
First Year ◽  
Population Total ◽  
The Third ◽  
Growing Seasons ◽  
Second Year ◽  
Efficient Selection ◽  
Selection Of

In order to establish an efficient selection criterion the variability in three asparagus populations was evaluated defining the most important yield components and analysing its evolution along three growing seasons. The yield components, coefficient of variation (CV) and the proportion of plants contributing to 80% of the total yield were estimated. The elite plants were selected by mean of total yield and clusters techniques. Multiple regression showed that spear number (SN) and spear weight (SW) were the most important yield components. In every population, total yield (TY) and SN showed the highest values of CV, independently of sex. 69% of the plants contributed to the 80% of the total yield in the first year while in the second and third year the contribution was 57%. At the end of the third year, 17 plants were selected by the average of the total yield and 43 by clusters. It is suggested to select for SW in the first year, reducing in 68% the experimental material. In the second year, the selection for SN would reduce to 5% the plants to evaluate for total yield in the third year. In this way the selected plants are the same but the number of plants to evaluate is dramatically reduced along the years, therefore facilitating the breeders work.

Long-term softening of surface and buried hard seeds of yellow serradella grown in a range of environments

1998 ◽  
Vol 49 (4) ◽  
pp. 673 ◽  
Author(s):  
C. K. Revell ◽  
G. B. Taylor ◽  
P. S. Cocks
Keyword(s):  
Laboratory Tests ◽  
Soil Surface ◽  
First Year ◽  
Mediterranean Environment ◽  
The Third ◽  
Hard Seeds ◽  
Ornithopus Compressus ◽  
Alternating Temperature ◽  
One Year

A 3-year field experiment was conducted to investigate seed softening in yellow serradella (Ornithopus compressus L.) in a low rainfall Mediterranean environment at Merredin, Western Australia. The study examined seeds of 4 accessions of serradella from separate growing sites (Pindar, Merredin, and Badgingarra), and included the effect of pod burial (only for accessions grown at Merredin). Pods were placed on the soil surface in December 1992 and sampled in March, June, and October for the next 3 years. Burial treatments (2 and 6 cm beneath the surface) commenced in June 1993 after pods had been on the soil surface for one summer. Samples were collected in June for the next 2 years. Softening of seeds over the first summer in the field was compared with that obtained in the laboratory with 16 weeks at a diurnally alternating temperature of 60/15ºC. Few seeds of any accession softened (generally <6%) at the soil surface during the first summer but the rate of softening increased over the next 2 years. The highest annual rate of softening was about 55% in the third year in accessions GEH72-1A and GEH72-2A. Accession of serradella hadmore influence on pattern of seed softening than site at which seeds were produced. Burial of pods at 2 cm markedly accelerated seed softening in all strains, particularly GEH72-1A and cv. Madeira, in which over 95% of hard seeds softened during the first year of burial. Softening at 6 cm was similar to that at the soil surface. Shallow burial of pods, as would occur during cereal cropping in one year,could improve regeneration of serradella, but reduce the longevity of its seed bank. Laboratory treatment at 60/15ºC generally over-estimated field softening during the first summer.The spread of germination in time in laboratory tests differed between accessions and was much wider in GEH72-2A than in others, extending up to 35 days. Such behaviour could provide insurance against total seedling loss following false breaks of season.

Hardseededness and the pattern of softening in Biserrula pelecinus L., Ornithopus compressus L., and Trifolium subterraneum L. seeds

1999 ◽  
Vol 50 (6) ◽  
pp. 1073 ◽  
Author(s):  
A. Loi ◽  
P. S. Cocks ◽  
J. G. Howieson ◽  
S. J. Carr
Keyword(s):  
Seed Bank ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Farming System ◽  
First Year ◽  
Ley Farming ◽  
Sufficient Variation ◽  
Depth Of Burial ◽  
Selection Of

Experiments measuring seed bank size, hardseededness, and seed softening of biserrula (Biserrula pelecinus L.) were conducted at Merredin and Perth in Western Australia. At Merredin, a mixture of 2 biserrula accessions was grazed, shallow cultivated, or left uncultivated and ungrazed. Seed bank size, seedling regeneration, and seed softening were measured over 2 years. At Perth, softening of biserrula, yellow serradella, and subterranean clover seeds grown at 2 sites (Binnu and Northam) was compared on the soil surface and after burial at 2 and 10 cm over a period of 2 years. Seed bank size of biserrula at Merredin ranged from 14000 to 17500 seeds/m2. Regeneration was greater in the second year (800–1700 seedlings/m2) than in the first year (40–600 seedlings/m2). In both years the shallow cultivated treatment recorded the highest number of seedlings. About 90% of biserrula and serradella seed remained hard after 2 years on the soil surface, compared with only about 10% of subterranean clover. Serradella softened more rapidly when buried 2 cm below the soil surface (8–12% hard) than it did on the soil surface (84–92% hard) (P<0.05). In contrast, the softening of subterranean clover decreased with increasing depth. Biserrula was intermediate, although it too softened most rapidly at 2 cm (78–95% hard compared with 82–97% on the surface) (P<0.05). Rate of seed softening in all species decreased with increasing depth of burial below 2 cm. Of the 4 accessions of biserrula, an accession from Greece (83% hard after 2 years exposure) was significantly softer than the other accessions. The results indicate that biserrula is very hardseeded, although there is sufficient variation in hardseededness for the selection of somewhat softer lines. Its pattern of softening suggests that biserrula may be successful in the ley farming system (crop/pasture rotations) of southern Australia.

Kesulitan Mahasiswa Pembelajar Pemula Bahasa Perancis dalam Memahami Gramatika

Metahumaniora ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 354
Author(s):  
Ferli Hasanah
Keyword(s):  
French Literature ◽  
French Language ◽  
First Year ◽  
The Common ◽  
French Grammar ◽  
Bahasa Indonesia ◽  
Selection Of

ABSTRAKGramatika pada setiap bahasa memiliki kekhasannya masing-masing.Mahasiswa Program Studi Sastra Perancis tahun pertama sebagai pembelajar pemulasering mengalami kesulitan dalam memahami gramatika bahasa. Kesulitan mereka tidakterlepas dari perbedaan-perbedaan mendasar pada struktur bahasa Indonesia sebagaibahasa ibu mereka dan bahasa Perancis yang tengah dipelajari. Penelitian ini dilaksanakandengan tujuan untuk mengetahui hambatan yang dimiliki mahasiswa pembelajar pemuladi Program Studi Sastra Perancis Universitas Padjadjaran dalam memahami gramatikabahasa Perancis. Metode yang digunakan dalam penelitian ini adalah metode simak dancatat. Hasil analisis ini menunjukkan bahwa kesalahan-kesalahan yang umum dilakukanpembelajar pemula ada pada penggunaan accent, konjugasi verba, partikel défini maupunindéfini, accord penanda feminin atau jamak, serta pemilihan preposisi.Kata kunci: gramatika, bahasa Perancis, konjugasiABST RACTThe grammar in every language has its own particularities. French literaturestudents in the first year as a beginner learners often have problem in understandingFrench grammar which is frequently considered difficult. Their struggle is inseparablefrom the fundamental differences between Indonesian structure as their mother tongueand the French language which being studied. This research aims to know the obstaclesof the students of beginner learners in the French Literature of Padjadjaran university inunderstanding the basic French grammar. The method used in this research is referringand taking notes method. The results of the analysis shows that the common mistakes oflearners are in the use of accents, verb conjugations, particles défini or indéfini, markeraccord feminine or plural, and the selection of prepositions.Keywords: grammar, French, conjugation

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