Volume 1, No. 1, 1976

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(pp. 1-9)
Differentiation of Soybean Cultivars by Seedling Pigmentation Patterns1
R. C. Payne and L. F. Morris2
Sixty-three soybean cultivars were grown in the laboratory under high intensity light and in the field. Six cultivar specific seedling pigmentation patterns were observed. Variation in pigmentation patterns due to the effect of different light intensities and nutrient solutions were detected. Results indicate that identification of seedling pigmentation patterns is a valuable approach for differentiating soybean cultivars.
Additional index words: Glycine max (L.) Merr., cultivar differentiation.
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(pp. 10-16)
Seedling Growth and Clone Performance in Western Wheatgrass,  Agropyron smithii Rydb.1
Ferdinand A. Quinones and Patrick L. Gose2
Sixteen clones of western wheatgrass were studied to determine differences in seedling growth traits. The data from 11 of the clones were correlated with the agronomic performance in a field test to ascertain if seedling growth traits in the laboratory could be used in selecting clones with better field performance under irrigated conditions. Three of the clones were significantly better (P < .05) than the check in germination, plumule growth, radicle growth and total growth.

No significant associations of plant breeding value were found between these four seedling traits and six field agronomic performance characters. Although the test with this limited number of clones did not suggest the use of seedling growth traits as an aid in selecting agronomic characters, it indicated the presence of significant differences in the growth from seed of different clones. It appears that further studies of these differences as to their relationships with range emergence and establishment should be conducted.
Additional index words: germination, correlation, plant breeding, agronomic performance.
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(pp. 17-30)
Tetrazolium Seed Testing Developments in North America1
R.P. Moore2
The first enduring use of vital stains for seed evaluation in America was initiated at Ohio State University in 1938 and involved selenium and tellurium salts. Knowledge of the existence and merits of tetrazolium, a non-poisonous vital indicator, was first received in America in 1945 from U. S. Military personnel who investigated research activities in Germany.
Initial tetrazolium studies in America were by Iowa State University, Boyce Thompson Institute and Pioneer Hi-Bred Corn Company. Reports concerning partial successes, limitations and problems became available in 1948.

Many of the obvious problems encountered during the early period of tetrazolium testing in America had been previously encountered and resolved in Germany. American investigators likewise needed time to experience, recognize and correct traditional misconceptions about seed life. Voids in knowledge had to be filled. Experiences had to be gained. Desired success in tetrazolium testing seemed slightly out of reach of early American investigators.
Subsequent studies, especially at Iowa, Mississippi, North Carolina, and Oregon State Universities and at the Virginia State Seed laboratory, gradually provided segments of knowledge, experience and philosophy needed for perfection and successful use of the test for a large number of crops.
The acceptance of the test by the Association of Official Seed Analysts in 1970 represented an important milestone in the science of seed evaluation in America. The test is now accepted as another useful method of evaluating seed quality.
The tetrazolium test is sound, however, competent analysts are indispensable for its successful use.
Additional index words: selenium, tellurium, vital indicator, viability.
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(pp. 31-43)
Radiofrequency Electrical Treatment Effects on Dormancy and Longevity of Seed1
S. O. Nelson, R. M. Heckert, L. E. Stetson, and W. W. Wolf2
Seed lots of seven small-seeded legume species and winter oats, winter rye, and perennial ryegrass were exposed to 39 MHz electric fields of known field intensities for various time periods and tested for germination response. The radiofrequency (RF) treatments effectively increased germination of alfalfa, red clover, and ladino clover through reduction of hard seed percentages. Significant increases in germination for these three species, as a result of electrical treatment, were retained in temperature- and humidity controlled
storage for 14 years.

Differences between treated and untreated samples held in a seed warehouse without temperature and humidity control tended to disappear after a few years because hard seeds became permeable naturally as the seeds aged. RF treatments overcame postharvest dormancy in winter oats. They did not affect the longevity of winter rye seed held for 6 years after treatment.
Additional index words: seed treatment, legume seed, germination.
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(pp. 44-54)
Improving the Germination of Indian Ricegrass Seeds1
Miller B. McDonald, Jr.2
Germination of Indian ricegrass [Oryzopsis hymenoides (Roem. & Schult.) Ricker] seeds was enhanced by scarification with concentrated sulfuric acid for 3 5 min. Additions of 100 μM GA3 and 40 % maneb further increased scarified seed germination by reducing post-harvest dormancy and controlling contamination from storage fungi.

Seeds treated in this manner germinated at 86 % after only 7 days at 30 C compared to 6 % germination  following 49 days at 15 C as recommended by the AOSA Rules for Testing Seeds. These techniques appear viable alternatives to methods currently employed for the germination and testing of Indian ricegrass seeds.
Additional index words: scarification, maneb,  gibberellic acid, storage fungi, prechilling, Oryzopsis hymenoides.
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(pp. 55-59)
Pythium aphanidermatum Seedborne on Squash: A Cause of Seed and Seedling Rot1
G. E. Harman, S. W. Braverman, and E. C. Waters2
Several lots of squash (Cucurbita pepo L.) seeds submitted for germination testing rotted during the tests. Rhizopus, Mucor, Pythium, Fusarium and Chaetomium were isolated from infested seed lots. A Pythium subsequently identified as P. aphanidermatum caused the rot in germination tests. Noninfested Butternut squash seeds planted in sand infested with P. aphanidermatum oospores were also killed.
Additional index words: Curcurbita pepo L.
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(pp. 60-63)
Effect of Selected Growth Retardants on the Germinability of Weed Seeds
Ajoy G. Chakrabarti1
Effects of B-nine (N, N-dimethylaminosuccinamic acid) and Phosfon D (Tributyl-2, 4-dichlorobenzyl-phosphonium chloride) on weed seed germination were studied. These growth retardants were applied at 1, 10 and 100 ppm concentrations on seeds kept in petri dish germinators. B-nine applied at 1 ppm concentrations decreased germination of cocklebur and pigweed seeds and at 100 ppm, decreased germination of pigweed and wild mustard seeds. Other concentrations of the growth retardants did not exhibit significant differences compared to the control.

Phosfon D decreased germination of cocklebur and pigweed seeds at all concentrations applied. The time required for germination was increased about a week in cocklebur seeds when treated with 1 ppm B-nine and in pigweed seeds when treated with 1 and 10 ppm of B-nine.
Additional index words: growth retardants, weed seeds.
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(pp. 64-70)
Weight and Packing Density of Crownvetch Seed in Relation to Year of Production and Germination1
G. W. McKee, W. P. Ditmer and Ho Jin Lee2
Samples fromn 140 commercial seedlots of Penngift crownvetch produced by one producer over the period 1968 to 1974 inclusive were measured to determine seed weight and packing density (volume weight). Mean weight per 1,000 seeds at 10% moisture was 3.657 g and seeds per kg 273,600 (124,400 seeds/lb). Mean packing density was 0.795 g/cc.

For all seedlots combined, weight 11,000 seeds, packing density, percentage hard seeds, and percentage total germination (ready germination plus hard seeds) were significantly correlated at the 1 % level. Seedlots produced during years with above normal rainfall during the growing season and below normal accumulated heat units and solar and sky radiation were somewhat lower in content of hard seeds and total germination than lots produced during years with normal to below normal rainfall and normal to higher than normal accumulations of heat units and solar and sky radiation.
Additional index words: Coronilla varia L., seeds/kg, seeds/lb, volume weight, seed density, seed maturity, growing season, temperature, precipitation, solar radiation.
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(pp. 71-78)
A Referee test of the Blotter and Guaiacol Agar Methods for the Detection of Helminthosporium oryzae and Trichoconis padwickii in Rice Seeds1
M. M. Kulik and E. J. Koch2
The blotter and guaiacol agar methods were used in a referee test to  detect Helminthosporium oryzae and Trichoconis padwickii in 10 lots of rice seeds. The guaiacol agar method was judged to be more sensitive than the blotter method for detection of H. oryzae since a significantly higher percentage of this fungus was detected with it. However, the guaiacol agar method was not more sensitive than the blotter method for the detection of Trichoconis padwickii.

The standard deviations were only slightly smaller for the guaiacol agar method than for the blotter method. With both methods, mean percent infection differed significantly among laboratories and indicated that neither method was completely satisfactory for detecting these two pathogens.
Additional index words: seed-borne disease, referee analysis.
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The Effect of Temperature, Light, and Growth Promoters on Seed Dormancy in Western Wheatgrass Seed1
Q. E. Schultz and R. C. Kinch2
Western wheatgrass, Agropyron smithii (Rydb.), seed was tested by four seed treatment methods differing from the standard germination procedure (darkness, alternating temperature) to determine their relative effectiveness in breaking dormancy.
Exposure to a constant 24 C temperature or to fluorescent white light strongly inhibited germination. Exposure to far red light produced an effect similar to complete darkness.

Red light was partially effective in breaking dormancy, but exposures exceeding eight minutes delayed the release from dormancy.
A 0.2% KNO3 solution was more effective in breaking dormancy than either gibberellic acid or kinetin.
Tetrazolium tests showed that none of the above treatments were completely effective in breaking dormancy.
Additional index words: germination, red light, far red light, KNO3, gibberellic acid, kinetin.
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(pp. 86-95)
Testing Coated Seed: Germination and Moisture Absorption Properties1
Eric E. Roos and Gregory S. Jackson2
Seed coatings on carrot (Daucus carota L.), lettuce (Lactuca sativa L.), and onion (Allium cepa L.) from four commercial sources were found to vary widely in their hydrophobic or hydrophylic properties. Too much or too little moisture in the planting medium inhibited radicle emergence of coated seed in standard tests for some samples. By carefully controlling substrate moisture, coated seed can be tested satisfactorily without removing the coating material.
Additional index words: laboratory germination, blotter test, pelleted seed, seed hydration, substrate moisture, radicle emergence.
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(pp. 96-103)
The Weibull Function: A New Method of Comparing Seed Vigor
F. T. Bonner and T. R. Dell1
The three-parameter Weibull function can be used to compare germination responses and to quantify the differences for use in statistical analyses. Data from germination of several lots of white oak and sweetgum were used to illustrate how the Weibull parameters reflect quantitative differences in seed vigor. Besides vigor comparisons, other possible uses of the Weibull are in tests of prechill treatments, chemical treatments, and varietal or geographic seed source differences.
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