scholarly journals Studies on the Hard Seed of Milk Vetch (Astragalus cinicus L.) : I Hard seed content of milk vetch in relation to its blooming time and maturing period.

1959 ◽  
Vol 27 (2) ◽  
pp. 289-292 ◽  
Author(s):  
Tasuke YASUE ◽  
Katsuichi OTA
Keyword(s):  
Hard Seed ◽  
Seed Content

scholarly journals Studies on the variation and inheritance of the hard seed content of Renge (Astragalus sileicus L, ).

1963 ◽  
Vol 13 (1) ◽  
pp. 21-24 ◽  
Author(s):  
Katsumi SYAKUDO ◽  
Syutaro KAWABATA ◽  
Motoi MURATA
Keyword(s):  
Hard Seed ◽  
Seed Content

Hard-seed content of alfalfa grown in Canada

1991 ◽  
Vol 71 (2) ◽  
pp. 437-444 ◽  
Author(s):  
D. T. Fairey ◽  
L. P. Lefkovitch
Keyword(s):  
British Columbia ◽  
Geographic Location ◽  
Viable Seed ◽  
Hard Seed ◽  
Peace River ◽  
Seed Content ◽  
River Region ◽  
Hard Seeds ◽  
Viable Seeds ◽  
Production Areas

The hard-seed content of alfalfa (Medicago spp.) grown in Canada in relation to genotype and geographic location of production was surveyed for the commercial growing regions in Manitoba, Saskatchewan, Alberta and British Columbia. The average hard-seed content of all pedigreed production over a 5-yr period, ranged from 22 to 37% and that in nonpedigreed production was between 14 and 30%. A database of the five widely grown cultivars revealed that the hard-seed content of alfalfa in the most northerly growing areas in the Peace River region of Alberta and British Columbia ranged from 31 to 51%, while hard seed content of alfalfa produced elsewhere varied from 22 to 38%. There was no apparent effect of latitude on the proportion of hard seeds, while there was a small increase for two of the five cultivars in production areas further west. Of particular interest was the trend in viable seed production. There was consistent evidence suggesting that the proportion of viable seeds decreased in production areas further north, but increased in production areas further west. However, the minimum viability was always in excess of 85%. There was no correlation between hard and viable seed. Key words: Medicago spp., alfalfa, lucerne, hard seeds, viable seeds

Variation in the rate of hard seed breakdown of twelve tropical legumes in response to two temperature regimes in the laboratory

2000 ◽  
Vol 40 (3) ◽  
pp. 387 ◽  
Author(s):  
C. K. McDonald
Keyword(s):  
Evaluation Studies ◽  
Field Evaluation ◽  
Threshold Temperature ◽  
Breakdown Rate ◽  
Hard Seed ◽  
Temperature Regimes ◽  
Seed Content ◽  
Tropical Legumes ◽  
Breakdown Rates ◽  
Threshold Temperatures

Hard seed content is an important factor in the persistence of tropical pasture legumes as both high and low hard seed content can lead to poor recruitment. As temperature plays an important role in the breakdown of hard seed, the patterns of breakdown were measured in 27 seed lots of tropical legumes subjected to temperature regimes of 23–57˚C and 23–70˚C in laboratory ovens for 7 months. The seed lots represented 12 species comprising 15 released cultivars and 5 accessions showing promise in field evaluation studies. Each month seed was removed for germination testing and the proportion of hard, soft and dead seed in each seed lot was determined. After 7 months, the resulting pattern of hard seed breakdown was modelled to derive threshold temperatures for hard seed breakdown, values for the breakdown rate and quantification of the breakdown process. Desmanthus virgatus and Indigofera schimperi had the slowest rate of breakdown, while Aeschynomene americana had the fastest. The threshold temperature for most species was in the range 40–50˚C. However, there was considerable variation in threshold temperature and breakdown rates between seed lots of the same cultivar or accession and between species, which indicates that caution must be used before extrapolating the results to the field and to different climatic and/or management environments. Nevertheless, these results provide valuable information for the development of demographic models of legume persistence, and show that, while the species are well adapted to the temperature environments of northern Australia, specific management may be necessary to enhance the persistence of some of them.

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.

High temperature contact treatment of hard seed in Stylosanthes

1979 ◽  
Vol 30 (5) ◽  
pp. 847 ◽  
Author(s):  
JJ Mott
Keyword(s):  
High Temperature ◽  
High Surface ◽  
Contact Period ◽  
Rotating Drum ◽  
Optimum Temperature ◽  
Hard Seed ◽  
Stylosanthes Humilis ◽  
Seed Content ◽  
Metal Plates ◽  
Palisade Cells

Samples of hard seed of Stylosanthes humilis, S. hamata, S. scabra and S. viscosa were agitated on high temperature metal plates in order to reduce the hard seed content. The optimum temperature for reduction of hard seed was found to be 140–150°C, with a contact period of 15–30 s, and hard seed content was reduced by up to 70%. Internal seed temperatures generally remained below 70° during this treatment, and there was little loss of viability. As with percussion treatments, imbibition took place through the strophiole, which indicates that break of hard seed occurred by mechanical stresses fracturing the palisade cells at the strophiole. On the basis of this principle of high surface temperatures and brief seed contact, a heated rotating drum was constructed and successfully used to treat bulk quantities of hard seed.

Dormancy and Field Burial of Cowpea (Vigna unguiculata) Seed

Weed Science ◽  
1986 ◽  
Vol 34 (2) ◽  
pp. 260-265 ◽  
Author(s):  
Tim R. Murphy ◽  
Billy J. Gossett ◽  
Joe E. Toler
Keyword(s):  
Water Content ◽  
Vigna Unguiculata ◽  
Initial Water Content ◽  
Initial Water ◽  
Hard Seed ◽  
Black Clay ◽  
Seed Content ◽  
Cowpea Seed ◽  
Concentrated Sulfuric Acid ◽  
Seed Water Content

Seed dormancy and soil longevity characteristics of three weedy cowpea [Vigna unguiculata(L.) Walp.] cultivars were investigated. Seed germination was maximum at 40 C; however, ‘Clay’ had greater germination than ‘Black’ or ‘Red Ripper’ cowpea at temperatures ≥ 20 C. Concentrated sulfuric acid soaks, hot (70 C)-water soaks, and piercing the seed coat promoted germination. Seed with an initial water content of 12.3% were stored at relative humidities ranging from 0 to 60% at 25 C. After 4 weeks of storage at relative humidities of 0 to 50%, seed water content varied from 4.6 to 11.4%. Germination and hard seed content was 11% or more and 89% or less, respectively, for seed with water content ranging from 6.9 to 11.4%. Except for seed with an initial water content of 6.9%, cowpea seed water content increased after 3 weeks of storage in a 70% relative humidity environment. Rehydration increased germination for seed with initial water content of 9.2% or more, but not for seed with initial water content of 8.4% or less. In mid-November 1981 and 1982, Black, Clay, Red Ripper, and sicklepod (Cassia obtusifoliaL. # CASOB) seed were buried at soil depths of 2.5, 7.5, and 15 cm for 3, 6, and 9 months. Seed survival of Black and Red Ripper was similar to that of sicklepod; however, longevity of Clay seed was less than sicklepod. Survival was greater for seed buried in 1981 than in 1982 because of low seed water content of the 1981 seedlots.

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