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Seed Certification in North America, Proud History—Two Perspectives on the Future
Individual Reviews by Larry Svajgr and by L. O. Copeland
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.
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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Effect of NaCl and Pro-Gibb T Priming Treatments on Germination of ‘Tam Veracruz’ and ‘Early Jalapeño’ Chile (Capsicum annuum) Seed
Anne K. Carter
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.
Moisture Content and Water Activity Determination of Pelleted and Film-Coated Seeds
A. G. Taylor,* D. F. Grabe and D. H. Paine
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.
RAPD Fragment Profiles from Deteriorating Soybean Seeds
J.Marcos-Filho,* M. B.McDonald , D. M. TeKrony and J. Zhang
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.
Effect of Impermeable Seed Coat on Germination of Seed from Early Maturing Soybean
Jeff M. Tyler
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.
Reduction of Summer Storage Temperatures to Improve Carryover Quality of Soybean Seed
E. Fabrizius, D. M. TeKrony* and D. B. Egli
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).
Germination Requirements of Penstemon penlandii an Endangered Species
J.E. Laufmann* and L.E.Wiesner
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.
Evaluation of Seed Vigor Tests for Canola
S.G. Elias and L.O. Copeland*
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.
Comparison of Three Methods of Purity Testing for Lolium multiflorum, L. perenne and Festuca arundinacea
Deborah J. Lionakis Meyer
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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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
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.
The Saturated Salt Accelerated Aging Test of Pansy and Impatiens Seeds
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.