Volume 23, No. 2, 2001

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(pp. 113-125)
Viability Constants for Delphinium and Salvia Seeds
Francis Kwong, Linda Stodolski, Jolan Mari, Sunitha H. Gurusinghe and Kent J. Bradford*
The dependence of seed storage life (longevity) on temperature and moisture content can be quantified and predicted using the seed viability equation. Survival data during storage of seeds of two varieties each of delphinium (Delphinium elatum L.) and salvia (Salvia splendens F.) at two temperatures (20 and 30 °C) and five relative humidities (33, 43, 53, 62, and 75%) were used to determine the constants of the seed viability equation.

Normal seedling or radicle emergence scoring criteria for germination tests to assess seed viability were also compared. For salvia seeds, both criteria gave closely correlated results, while normal seedling counts were more reliable for delphinium seeds. Our results confirm the applicability of the seed viability equation for quantifying seed storage behavior, and provide values for the constants of the seed viability equation for two ornamental flower species.
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(pp. 126-137)
Physiological Seed Quality, Seedling Lipid and Protein Content of Soybean (Glycine max (L.) Merrill), in Response to Different Concentrations of "-hydroxybenzoic Acid
S. R. P. Schuab, A. L. Braccini*, O. Ferrarese Filho, C. A. Scapim
and M. C. L. Braccini
Phenolic acids are natural compounds in several plants, which can influence cell morphology, physiology and metabolism. It has also been observed that these compounds can affect seed germination. This study evaluated the influence of "ρ-hydroxybenzoic acid on seed germination and vigor, and quantified the total lipids and total soluble proteins in soybean seedlings.

Seeds of the cultivar BR-37 were planted on paper towels at different concentrations (0; 0.1; 1.0; 5.0; 10.0 mM) of "ρ-hydroxybenzoic acid and germinated at 25°C for 8 days. Evaluations were made for: germination, radicle and hypocotyl length, as well as fresh and dry biomass. The lipid contents of cotyledons and proteins in the three components (radicle, hypocotyl and cotyledons) of seedlings were assessed after 7 days at 25°C. The results showed that there were no significant differences in cumulative seed germination (radicle emergence) in the presence of the compound studied. However, the percentage of normal seedlings at the final (8 days) count declined sharply from 70% (control) to 7.1% at 10.0mM "-hydroxybenzoic acid. A significant reduction in the length, fresh and dry biomass of radicles was observed as concentration increased. A decrease of lipid content was found in cotyledons, and an increase of protein content was shown at high concentrations of the phenolic compound. The results showed that "ρ-hydroxybenzoic acid negatively affects not only seed germination, seedling growth and development, but also the metabolism of lipids and proteins.
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(pp. 138-144)
Light and Temperature Dependence for Germination and Emergence of White Horehound (Marrubium vulgare L.) Seeds
Stefano Benvenuti*, Laura Andolfi and Mario Macchia
Seed germination requirements of white horehound (Marrubium vulgare L.) were investigated to improve agronomic knowledge of this species and allow its cultivation as a medicinal plant. Fresh seeds of white horehound were positively photoblastic and capable of germinating throughout the temperature range examined (10–40 °C), with highest  percent germination at 30–35 °C.

In this range of constant temperatures, over half the seeds remained dormant. Dormancy breaking was achieved by incubating seeds at alternating temperatures.With increasing range of temperature fluctuation, seed dormancy decreased to the point of abolishing the light requirement for germination. Far-red light inhibited germination. Germination was inhibited proportionately into depth of burial in peat-perlite. However, incubation of buried seeds in alternating temperatures in dark attenuated this inhibition. In conclusion, our germination tests evidenced that temperature fluctuations of the substrate represent the crucial environmental parameter for the germination and emergence of buried seeds. Consequently, the typical thermal fluctuations of spring appear to be suitable for the agronomic propagation of this species.
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(pp. 145-150)
Prechill Temperature and Duration are Important in Determining Seed Quality for 12 Wildflowers
Susana H. A. C.Mogensen; Phil S. Allen* and Susan E.Meyer
Germination tests for seeds of many species require moist prechill at 2–5 °C to break dormancy. In practice, however, seeds are sometimes prechilled at temperatures as high as 10 °C. To document the importance of prechill temperature and duration, seeds of 12 wildflower species native to Utah (Balsamorhiza sagittata, Castilleja applegatei, C. chromosa, C. flava, C. linearifolia, C. rhexifolia, C. scabrida, Cleome serrulata, Pedicularis groenlandica, Penstemon cyananthus, P. eatonii and P. sepalulus) were subjected to a series of laboratory germination treatments

with 0, 4, 8, 12 and 16 weeks of prechill at 1, 3, 5, and 7 °C followed by 4 weeks of incubation at 10/20 °C. Viability evaluation for each species was estimated using a tetrazolium test. Seeds of all species were dormant without prechill, and very few of the collections showed a significant response to 4-week prechill. Prechill at 7 °C was largely ineffective and only C. linearifolia and C. serrulata responded to prechill at 5 °C. Seeds of P. cyananthus and C. flava responded positively to prechill, but 3 °C resulted in slightly higher germination than did 1 °C. P. eatonii and P. sepalulus required more than 8 weeks of prechill at 1 or 3 °C for germination to exceed 35%. For seeds of B. sagittata, C. scabrida and C. chromosa, germination response increased with increasing prechill duration up to 16 weeks. Finally, C. rhexifolia, C. applegatei and P. groenlandica had maximum germination percentages < 40%, regardless of prechill temperature or duration. Discrepancies between maximum germination percentages and total viability indicate that prechill for periods longer than 16 weeks may be necessary for many seeds to germinate. Because such long periods are impractical for seed testing, tetrazolium staining or germination tests that include the use of dormancy-breaking chemicals should be considered.
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(pp. 151-161)
Evaluation of the Physiological Potential of Tomato Seeds by Germination and Vigor Tests
M. Panobianco and J.Marcos-Filho*
This study was conducted to assess the efficacy of different vigor tests to evaluate physiological potential of tomato (Lycopersicon lycopersicum L.) seeds. Five seed lots of cultivars ‘Debora Plus’ and ‘Bruna’ were subjected to the standard germination, greenhouse seedling emergence, electrical conductivity, potassium leachate, accelerated aging, saturated salt accelerated aging and controlled deterioration tests.

Results indicated that both accelerated aging procedures and controlled deterioration tests were the most efficient for evaluating tomato seed vigor, allowing the identification of different levels of seed quality. The potassium leachate test was a promising option primarily to identify tomato seed lots of lower physiological quality in a considerably reduced evaluation time. The electrical conductivity test was a less sensitive vigor test for tomato seeds since the evaluation of the release of electrolytes from the seeds was a less precise seed quality parameter. These results provide useful information regarding the assessment of tomato seed vigor and the identification of the saturated salt accelerated aging and potassium leachate tests as new alternatives in successful seed quality control programs.
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(pp. 165-168)
Rolled Towel Bioassay to Identify Roundup Ready Trait in Cotton Planting Seed
Bryan R. Savoy*, Dennis A. Berkey, and Paul G. Johnson
Breeding and quality assurance programs need accurate and affordable methods to test for the presence of intended and unintended genes in transgenic cotton (Gossypium hirsutum L.) varieties. The objectives of this paper were to describe in detail the Roundup Ready® (RR) Rolled Towel Bioassay procedure for cotton planting seed and demonstrate the reliability of this test in identifying the intended RR trait in cotton seed.

Seedlings were evaluated as susceptible if they have a shortened hypocotyl-radicle length with characteristic black lesions on the hypocotyls. Results using the RR Rolled Towel Bioassay were comparable to the RR lateral flow strip tests in 678 compared seed samples. The RR Rolled Towel Bioassay is an accurate and cost effective way to detect the presence of the RR trait in cotton seed.
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(pp. 169-172)
Identification of Eriochloa villosa
Ken Allison* and Stephen Darbyshire
Woolly cupgrass, a weed species new to Canada, was found in Quebec in 2000. This is a potentially serious weed in the corn and soybean belt of southern Ontario and Quebec. Seed analysts are advised to watch for seeds of this species when conducting analyses. A brief history of the weed in North America is presented, along with illustrations and descriptions to aid in identification.
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(pp. 173-179)
Soybean Seed Referee for the Accelerated Aging Test —1999, 2000
Dennis TeKrony
Seed vigor tests must be standardized before they can be accepted by seed testing associations. The primary objective of these two referees was to determine the level of variability that occurs within and among seed laboratories when conducting the accelerated aging (AA) vigor test for soybean seed. The nine AOSA and SCST laboratories that participated in these referees all had previous experience with AA testing and the equipment needed (water jacketed chamber) to conduct the test.

All laboratories agreed to conduct both the standard germination (SG) and AA tests on replicated soybean seed samples that were coded for testing so that the identity of the seed lots was unknown in a blind referee. Only seed lots with acceptable standard germination, but a range in seed vigor were selected for the referees. There was greater variability among and within laboratories for AA germination than for standard germination, which was expected because of the lower germination scores and many more abnormal seedlings. The variability for AA was much greater in 1999 than in 2000 because of poor calibration of aging chamber temperature in three laboratories. Uniform AA results were achieved within and among seed laboratories in 2000. The data sets from these two referees were used by the ISTA Statistics committee to establish tolerance levels to be used for the AA test of seed vigor for soybean seed.
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(pp. 180-184)
Interaction Effect of Gibberellic Acid and Kinetin on Germination and α-amylase Activity in Barley Seeds
M. Zahid Rizvi., A. Ahmad* and S. Hayat
Gibberellic acid is the natural inducer of the activity of α-amylase, however, the presence of kinetin (an inducer of nitrate reductase activity), at an elevated level, was expected to be felt in the process of protein synthesis and the germination. Therefore, the grains of Hordeum vulgare (L) cv. PL-172 were soaked in aqueous solutions (10-6 M) of gibberellic acid and/or kinetin for 6, 12 or 24 hours.

The treatment improved percent germination of the grains and the activity of α-amylase, irrespective of the hormone and the soaking duration. However, the best response was generated in the grains soaked in gibberellic acid for 12 hours where germination and the level of the enzyme activity increased by 156% and 90% respectively, over the control.
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(pp. 187-196)
Noninvasive Seed Quality Test by Impedance Spectrum Analysis
D. H. Paine, T. Repo, A. G. Taylor*
Electrical impedance spectroscopy techniques were developed for use on single seeds of snap beans (Phaseolus vulgaris L.) to assess and predict their germination potential. These seeds were aged in a manner that provided a range of seed qualities for testing. The test protocol established was noninvasive, requires careful moisture content regulation and can be completed in 24 hours.

Two distinct dispersions were observed of which a low frequency dispersion correlated best with seed quality, and centered between 9.5 and 13.4 kHz with a real resistive component between 7 and 18Ω. The low resistive values corresponded to seeds of low quality compared with seeds having high values. The Voigt impedance model represented the data well enough to provide parameters that could predict germination with an accuracy of 0.93 (ROC). An ROC (receiver operating characteristic) of 0.5 is simply a prediction by chance, while a value of 1.0 would indicate a perfect prediction with no false negatives or false positives.
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(pp. 197-205)
Survival Characteristics of Inbred Corn Seed During Storage
Dennis M. TeKrony,* Dennis B. Egli and Marcy Rucker
A method of predicting the deterioration of corn (Zea mays L.) seed during storage would benefit seed producers and the seed industry. This investigation evaluated the ability of an alternative model and initial seed quality tests to predict changes in germination of inbred corn seed during storage in controlled environments. Eight fungicide treated seed lots with low levels of mechanical injury, high germination and a range in seed vigor were stored in sealed foil packets in six constant temperature and seed moisture environments: 20 °C, 14%; 30 °C, 12 and 14%; and 40 °C, 10, 12 and 14%.

Seed was sampled at regular intervals and tested for germination and moisture. Prior to storage the initial quality of each seed lot was determined by standard germination, cold test, accelerated germination and conductivity. In addition, the rate of deterioration and time to 50% loss of germination (P50)were estimated using a rapid aging test (40 °C, 15% seed moisture). The model accurately predicted the time to decline to P50 in three storage environments (40 °C, 14%; 40 °C, 12%; 30 °C, 14%), however, as P50 increased in improved storage conditions (40 °C, 10%; 30 °C, 12% and 20 °C, 14%), the predicted P50 was much larger than the observed P50, which limits the usefulness of the alternative model. The P50 from the rapid aging test was significantly correlated with P50 in all storage environments. The accelerated aging test, conducted at 45 °C, 72 h, was the only measure of initial seed vigor that was significantly correlated to P50 in most storage environments. Thus, rapid aging and accelerated aging can be used prior to storage to select seed lots with slow or rapid deterioration potential.
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