Volume 19, No. 1, 1997

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(pp. 5-15)
Seed Certification in North America, Proud History—Two Perspectives on the Future
Individual Reviews by Larry Svajgr and by L. O. Copeland
EDITOR’S COMMENTS:
Increased productivity has occurred in the USA for all agronomic and horticultural crops during the past fifty years. A major factor contributing to this increase was the use of improved crop cultivars that were initially developed by plant breeders at Agricultural Experiment Stations in each state. A second major factor that was essential for farmer use of these superior cultivars was a uniform system for the multiplication and distribution of high quality seed. Thus, seed certification programs were established in each state and seed standards were established nationally to insure genetically pure cultivars of high planting seed quality. 

Although the administration of these certification programs varies from state to state, they have successfully provided a vital link between the plant breeders who develop cultivars and the farmers who use them for many years.
During the past two decades, seed companies have established research programs to develop and market their own privately developed crop cultivars and brands. This has led to a decline in the role of publicly developed cultivars for several major crops (corn, wheat, soybean, and cotton). These same seed companies have also developed their own seed multiplication quality assurance programs, often following the seed certification format. Thus, seed certification agencies in each state are faced with new challenges in the 1990’s. To address this important issue, I have invited two qualified individuals, Mr. Larry Svajgr and Dr. Larry Copeland to provide their perspectives on the future of seed certification. Both have more than 25 years of experience working with seed certification programs in several states in the midwestern USA and a lifelong devotion to seed improvement and agriculture. I’m pleased that they have accepted this challenge and look forward to
reading their opinions. —D. TeKrony, editor

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(pp. 16-23)
Effect of NaCl and Pro-Gibb T Priming Treatments on Germination of ‘Tam Veracruz’ and ‘Early Jalapeño’ Chile (Capsicum annuum) Seed
Anne K. Carter
ABSTRACT:
Chile seed is known to have poor germination in the field at temperatures near 15°C. Use  of seed pre-treatments enhances germination, however, it is not known whether a combination of a priming solution plus gibberellin will have a synergistic effect on seed germination of chile. Therefore seeds of ‘Tam Veracruz’ and ‘Early Jalapeño’ chile were primed for five days at 23°C in solutions of 1) 0.3 M NaCl; 2) 4 μg Pro-Gibb T/g seed; 3) 0.3 M NaCl + 4 μg Pro-Gibb T/g seed; or 4) 18 mOhm H2O. Germination tests were run in petri dishes and flats of potting media in 23°C and 15°C incubators.

Final germination percentage (FGP) and the germination rate (MDG) were calculated. Over 70% of the seeds primed in H2O or Pro-Gibb T alone germinated during the priming process while seeds treated with NaCl or NaCl + Pro-Gibb T did not germinate. Under these conditions, Pro-Gibb T cannot be used alone as a seed pre-treatment. Both the NaCl treatment and the NaCl + Pro-Gibb T improved the germination rate compared to the control. The combination of priming plus gibberellin had a faster germination rate than when priming was used alone, especially at 15°C. Seed priming plus Pro-Gibb T can improve the emergence rate and overall performance of chile seed at less than optimal temperatures.
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(pp. 24-32)
Moisture Content and Water Activity Determination of Pelleted and Film-Coated Seeds
A. G. Taylor,* D. F. Grabe and D. H. Paine
ABSTRACT:
The purpose of this work was to test the accuracy of the oven method, capacitance meter and water activity measurements to assess the water status of intact pelleted and film-coated seeds in comparison with noncoated seeds. Seeds from one lettuce (Lactuca sativa) lot and one onion (Allium cepa) lot were pelleted by six commercial sources. A second lot of onion and one lot of cucumber (Cucumis sativus) were film coated by one company resulting in three different coating formulations.

A noncoated control was used as a comparison for each lot.Neither the oven method nor the capacitance meter were able to accurately determine the actual seed moisture content from intact pelleted seeds. The oven method underestimated the actual seed moisture content from film-coated seeds,while the capacitance readings provided similar or slightly lower values for film coated than for noncoated seeds. Overall, water activity measurements provided accurate determinations of water status from six pellet sources and three film coating formulations for two crops. The seed moisture content could be calculated from the water activity values with equations from the moisture isotherm for each crop. In conclusion, water activity measurements were a versatile method of assessing water status of coated and noncoated seeds on a routine basis.
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(pp. 33-44)
RAPD Fragment Profiles from Deteriorating Soybean Seeds
J.Marcos-Filho,* M. B.McDonald , D. M. TeKrony and J. Zhang
ABSTRACT:
Soybean [Glycine max (L.) Merrill.] seed deterioration occurs because of several  physiological factors. One model suggests that a primary event causing loss of seed quality is DNA degradation. To test this model, changes in DNA integrity occurring during seed aging were evaluated using RAPD (Random Amplified Polymorphic DNA) analyses.

Five soybean cultivars (Pennyrile, Corsica, Stafford, Essex and Pharaoh) represented by two seed lots each were evaluated after storage under ambient warehouse (0% germination) and cold room at 10 °C and 50% R.H. (68 to 94% germination) conditions for four to five years. The extraction, quantification, amplification of DNA templates, and electrophoresis were conducted using four primers. Evaluations were performed on samples of whole dry seeds and their constituent parts (embryo axes and cotyledons) of each seed lot. The results demonstrated no influence of seed deterioration on RAPD fragment expression under both storage conditions. Similar results were found for different seed tissues that displayed the same banding patterns as the whole seeds for each cultivar. This indicates that the standardization of RAPD protocols for varietal  identification testing of soybean seeds is feasible even when extreme differences in seed viability and vigor exist.
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(pp. 45-50)
Effect of Impermeable Seed Coat on Germination of Seed from Early Maturing Soybean
Jeff M. Tyler
ABSTRACT:
Recently some soybean [Glycine max (L.) Merr.] growers in the southern USA have shifted to early maturing cultivars to avoid drought, which often occurs during late summer. Seed quality of cultivars that mature early (August and early September) is often poor. The impermeable seed coat (ISC) trait has provided protection for seed exposed to late season weathering; however, it is not known if it will improve seed quality of early maturing soybean. The objective of this study was to determine the effect of ISC on germination of seed harvested from early maturing lines.

ISC and permeable seed coat (PSC) lines derived from the crosses D86-4565 X C1747 and D86-4565 X C1813 were studied. These lines ranged in maturity from late August to early October, when grown at Stoneville, MS in 1993 and 1994. Standard germination tests were used to assess effect. ISC lines were significantly higher in germination in one cross (D86-4565 X C1747) in 1993, but did not differ from PSC lines in either cross in 1994. There was a strong positive correlation (r = 0.63–0.75) between mean germination and maturity date in 1993 among lines within each seed coat class for both crosses. Maturity in 1994 was not correlated with germination except among PSC lines from the D86-4565 X C1747 population (r = -0.38). Results indicated that ISC was not consistently effective in protecting seed quality in early maturing lines. Several early maturing lines with PSC showed acceptable germination in both years indicating potential for improvement of this trait.
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(pp. 51-67)
Reduction of Summer Storage Temperatures to Improve Carryover Quality of Soybean Seed
E. Fabrizius, D. M. TeKrony* and D. B. Egli
ABSTRACT:
Although soybean [Glycine max (L.) Merr.] seed quality deteriorates rapidly, there has been interest in storing seed beyond the first planting season. The effect of reducing summer warehouse storage temperatures on seed germination, vigor and field emergence during two carryover years of storage was evaluated. Seed lots with acceptable standard germination (> 80%), but variable levels of vigor, mechanical injury and seed infection by Phomopsis longicolla Hobbs were placed in uncontrolled warehouse storage at two locations (Kentucky and Indiana).

Seed was sampled at three-month intervals for over two years and tested for germination and vigor (accelerated aging AA). Seventeen seed lots were moved from the warehouses to constant temperatures [13 (IN) or 16 (KY) °C] as summer temperatures increased above these levels and returned to the warehouse when temperatures declined below the same level. Seed lots infected with P. longicolla increased in seed germination and vigor as fungal viability declined during the first six months of storage in all storage environments. All seed lots stored continuously in the warehouse maintained > 80% germination through ~450 days of storage (one year carryover), but few had acceptable (> 80% AA) seed vigor. Reducing summer temperatures increased the seed vigor (2 to 54 percentage points) and field emergence (0 to 33 percentage points) of many seed lots. Most seed lots with > 80% AA germination initially (April, first year of storage) maintained adequate seed vigor (> 80% AA ) and field emergence after one year of carryover storage.High initial levels of mechanical injury or seed infection by P. longicolla had little effect on rate of deterioration and storability compared to sound seed lots in all storage environments. Reducing summer temperatures may provide a practical, economic option for carryover soybean seed in warehouse storage.
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(pp. 68-77)
Germination Requirements of Penstemon penlandii an Endangered Species
J.E. Laufmann* and L.E.Wiesner
ABSTRACT:
Seed dormancy exists in many of the 250 species of Penstemon, including Penstemon penlandii (an endangered species). These studies were conducted to develop a better understanding of dormancy in this species and provide protocols to determine the germination requirements of P. penlandii. P. penlandii seeds were collected at two locations near Kremmling, CO on 3 and 20 Aug. 1993 to obtain seeds of different maturity. Many dormancy breaking procedures were compared including prechilling, hydrogen peroxide, liquid nitrogen, hand clipping, mechanical scarification, acid scarification, gibberellic acid treatments, ultraviolet light exposure, light and dark exposures, and immersion in boiling water.

The germination and speed of germination results in individual germinators suggested that 15–30°C gave the highest percentage germination for P. penlandii after mechanical scarification, however there were no significant differences between 15–25°C and various other germination temperatures. Scarification rates of 30psi for 10 to 20 sec produced highest rates of germination and emergence in laboratory and greenhouse tests. Laboratory germinations at 15–30°C of mechanically scarified seeds were highly correlated with seedling emergence in the greenhouse. Submerging seeds in aerated 1mM GA3 for 24h, placing seed on water moistened blotters at 15–25°C, and hand scarifying ungerminated seeds after 14d followed by an additional week for germination provided results which were similar to hand scarification, mechanical scarification, and tetrazolium viability. This germination procedure has been adopted by the Association of Official Seed Analysts for inclusion in the “Rules for Testing Seed”.
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(pp. 78-87)
Evaluation of Seed Vigor Tests for Canola
S.G. Elias and L.O. Copeland*
ABSTRACT:
Field emergence and several seed vigor tests were used to evaluate the quality of different canola seed lots. Four seed lots representing two winter and two spring cultivars were aged at 42 °C at various time intervals to provide six sub-lots with a range of seed vigor. The six sub-lots were evaluated for seed quality using the following tests: cold, cold soil, conductivity, first count germination, standard germination and field emergence.

Aging seeds for 48 h at 42 °C followed by germination for 7 d at 22 °C was the best method for the accelerated aging test. Soaking 200 uninjured, untreated seeds for 16 h at 22 °C in 50 ml of distilled water was suitable for the conductivity test. The cold soil test was most successful in separating seed lots of different quality when seeds were planted on moist blotter paper, covered with soil and pre-treated for 5 d at 5 °C before germinating at 22 °C for 5 d. Incubation for 5 d at 5 °C without soil provided the best pre-germination treatment for the cold test. Temperatures of 22, 25 or 20/30 °C (alternating) in the standard germination test did not significantly differ in influencing germination results. Significant correlations were found between the results of all vigor tests and field emergence for all seed lots.
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(pp. 91-98)
Comparison of Three Methods of Purity Testing for Lolium multiflorum, L. perenne and Festuca arundinacea
Deborah J. Lionakis Meyer
ABSTRACT:
Comparisons among the AOSA and ISTA purity testing methods for annual ryegrass (Lolium multiflorum Lamarck), perennial ryegrass (L. perenne Lamarck) and tall fescue (Festuca arundinacea Schreber), and a new method in which only the large sterile structures are removed were made by the AOSA Purity Subcommittee. Pure seed percentage, time consumption, numbers and types of seed unit attachments and amount of inert material recovered from the attachments were examined. All three methods achieved similar results for the nine seed lots tested. The new method produced nearly identical results to the AOSA method for all three species tested with a considerable time savings.
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(pp. 99-102)
ROUNDUP™ Pre-emergence Treatment to Determine the Presence of the Roundup Ready™ Gene in Soybean Seed: A Laboratory Test.
 Iowa State University Procedure
A.S. Goggi* and M.G. Stahr
ABSTRACT:
A laboratory test for determining the presence of the Roundup Ready™ gene in soybean seeds was developed by the ISU Seed Testing Laboratory and approved by Monsanto. The procedure recommended to evaluate the percent expression of the Roundup Ready™ gene includes a seed lot of unknown tolerance and two controls, a susceptible soybean seed lot and a known Roundup Ready™soybean seed lot.

All seed lots are imbibed in a 2% solution of the ROUNDUP™ ULTRA formulation (41% active ingredient), for a concentration of 0.82% active ingredient, glyphosate, in the solution. Two replications of 100 seeds of each lot are placed overnight in paper towels treated with the ROUNDUP™ solutions. Imbibed seeds are then germinated following the prescribed procedure for soybeans (AOSA Rules for Testing Seeds) and evaluated after 7 days. A standard germination test is also planted to use as a comparison of the abnormal seedlings. Susceptible seeds present severe toxicity symptoms. Radicles of the affected seedlings are yellow to brown and stunted, with little or no secondary root growth. Seedlings of Roundup Ready™ soybeans develop normally.
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(pp. 103-109)
The Saturated Salt Accelerated Aging Test of Pansy and Impatiens Seeds
Miller B.McDonald
ABSTRACT:
The saturated salt accelerated aging (SSAA) test is a modification of the accelerated aging test protocol where salts are substituted for water to control the relative humidity of the aging environment. This process reduces the rate of water absorption into small-seeded crops thereby reducing their speed of deterioration. The purpose of this study was to examine the reproducibility of SSAA results for four pansy (Viola tricolor L.) (raw and primed) and two impatiens (Impatiens walleriana Hooker f.) seed lots using a referee format.

Eight laboratories participated in the referee and all seed lots were aged with saturated NaCl at 41°C for 72 h for pansy and 48 h for impatiens. Seeds were tested for germination before and following SSAA at 7 and 14 days. Similar standard germination results were obtained for the eight laboratories after 14 days. Seven of the eight laboratories produced similar SSAA results after 14 days for pansy and correctly identified the ranking of seed lot performance for impatiens. Primed pansy seeds were more prone to deterioration in the SSAA test. These findings indicate that standardization of the SSAA  test is possible.
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