Volume 30, No. 1, 2008

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Download abstracts (free download) from oral and poster presentations given at the 98th Association of Official Seed Analysts and the 85th Society of Commercial  Seed Technologists (AOSA/SCST) annual meeting held in St. Paul, Minnesota on June 5th–12th, 2008

(pp. 7-16)
Aged Switchgrass Seed Lot’s Response to Dormancy-breaking Chemicals
Gautam Sarath* and Robert B.Mitchell
Aged switchgrass seed lots can display various levels of dormancy. Understanding the causes for this dormancy will provide better insight into seed physiology, and potentially lead to treatments that reduce variability in seed germination assays.

The effects of sodium nitroprusside, potassium ferrocyanide and hydrogen peroxide on the germination of eight aged switchgrass (Panicum virgatum L.) seed lots, seven of which were produced  in the same year at a single experiment station, were examined. Seed germination demonstrated a significant seed lots × days and treatments × days effect. However, responses of individual seed lots to specific chemicals varied considerably. Genetically related seed lots did not display similar responses to the treatments, while switchgrass derived from a different germplasm exhibited a more similar response. Coleoptile emergence was significantly improved by chemical treatments and showed a significant seed lots × treatment interaction. Together, these results indicate (1) chemicals releasing reactive nitrogen species or peroxide can overcome residual dormancy and stimulate seed germination and coleoptile emergence in diverse switchgrass seed lots, and (2) multiple mechanisms, to some extent under genetic control, appear to direct switchgrass seed germination.
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(pp. 17-25)
Accelerated Aging Test as a Predictor of Seed Performance in Wheat
Joel K. Ransom* and Steve Sebesta
Research was conducted in 2005 and 2006 in eastern North Dakota to determine the value of the accelerated aging test in predicting field performance in hard red spring (Triticum aestivum L.) and durum (Triticum turgidum L. var. durum) wheat. Four seed lots from four different cultivars were selected each year with standard germination greater than 76% and a wide range of germination after accelerated aging. Seed lots were planted in field plots and their emergence and agronomic performance measured.

In 2005, seed lots within cultivars did not significantly differ in field emergence, yield or any other traits  measured at harvest. In 2006, seed-lots did differ in field emergence and yield, but differences could not be explained by the results of the accelerated aging test. In both 2005 and 2006, correlations between the accelerated aging test and field emergence and yield were not significant nor were correlations between the standard germination test and field emergence significant. The data indicate that the accelerated aging test is a poor predictor of field emergence and yield of hard red spring and durum wheat, within the context of the environments where the research was conducted.
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(pp. 26-36)
The Occurrence and Control of Pepper Mild Mottle Virus (PMMoV) in the USDA/ARS Capsicum Germplasm Collection
R. L. Jarret*, A. G. Gillaspie, N. A. Barkley and D. L. Pinnow
Four thousand-four-hundred and three seed inventories of Capsicum spp. obtained from the USDA/ARS Capsicum germplasm collection were tested for the presence of Pepper mild mottle virus (PMMoV). Approximately 32% of these inventories tested positive for PMMoV and the virus distribution was nearly uniform across the five cultivated species of this genus.

Treatment of PMMoV-infected Capsicum seed with 10% trisodium phosphate (TSP) for 2.5 h at room temperature reduced germination in 11/50 accessions examined and significantly increased the number of abnormal seedlings. Indicator plant [Chenopodium giganteum D. Don.—formerly C. amaranticolor (Coste & A. Reyn.) Coste & Reyn] analysis revealed that treatment of PMMoV infected Capsicum seed with 10% TSP for 2.5 h reduced virus infectivity, but did not eliminate it. Treatment with 10% TSP for 24 h eliminated PMMoV from four of six tested accessions. Short-term treatment of PMMoV-infected Capsicum seed with TSP prior to planting is expected to significantly reduce the incidence of the virus, but not eliminate it in all instances.
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(pp. 37-44)
Morphological and Agronomical Characterization and Diversity Analysis of Five Runner Bean (Phaseolus coccineus L.) Local Landraces Used in Organic Agriculture in Spain
D. Palmero* and C. Iglesias
This study presents a complete morphological and agronomic characterization of five local runner bean landrace cultivars, coming from an organic farm in Oteruelo del Valle (Madrid, Spain). The cultivars were evaluated following the descriptions of the Protocol for  Distinctness, Uniformity and Stability test of Phaseolus coccineus L. (CPVO-TP/009/1 Final). A distinctness analysis of the local landraces compared to 12 different commercial cultivars inscribed in the European Union Common Catalogue was carried out.

The results show a complete varietal description for each variety which allows differentiation the vegetable material selected by local farmers from the rest of the commercial varieties based in morphological and agronomical traits.This work will be the first step to later multiplication and conservation of the local material described, allowing the material used in organic agriculture to be included into breeding programs and possibly registering these local landraces as commercial varieties.
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(pp. 47-59)
Significance of Seed Size and Parent on Biomass and Morphological Variables of Quercus macrocarpa and Q. alba
Valasia Iakovoglou*, Richard B. Hall, Manjit K.Misra and Allen D. Knapp
Successful oak regeneration is problematic because of species competition, environmental stresses, and the biological limitations of the recalcitrant oak seeds. This study investigated the effect of seed size and parent tree on 3-month-old seedlings for biomass and morphological variables. Seeds of Quercus macrocarpa and Quercus alba were separated into different sizes.

Two Q. macrocarpa parent trees gave five “small” sizes (13 to 18 mm), while three parent trees gave five “large” sizes (18 to 23 mm). Two Q. alba parent trees gave three seed sizes (17 to 19 mm). Both seed size and parent affected seedling growth, with larger seeds performing better.  All the biomass variables increased as seed size increased. Regression analysis indicated that root dry weight is a good surrogate for root area. Leaf area and number of first order lateral roots increased, while specific leaf area (SLA) decreased with increase in seed size. This suggests that seed size affects early developmental stages, with larger seeds giving rise to more vigorous seedlings with characteristics, such as thicker leaves (lower SLA), that enhance establishment success. Conclusively, larger seeds of the studied recalcitrant species could promote regeneration success and benefit nursery practices by reducing production cost when regenerating a site by planting seeds as opposed to transplanting seedlings.
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(pp. 63-69)
Seed Germination Response of Populations of Swertia chirayita [(Roxb. ex Fleming) H. Karst] Following Periodical Storage
Bharat K. Pradhan and Hemant K. Badola*
Swertia chirayita, a critically endangered and high value Himalayan medicinal herb was investigated to understand response of different populations on initial seed germination, and germination after storage at 4 °C for 18 months. Populations differed significantly for seed characteristics, indicating considerable genetic diversity. Of 13 populations tested, eight exhibited 100% germination immediately after collection, which was negatively correlated with altitude of the sites where plants were growing.

The results suggested an acceptable range of 16 to 42% seed moisture content, before storage, as suitable criteria for S. chirayita populations in long term gene resource conservation. Seed from 10 plant populations showed a steady decline in germination over the storage period. Varied germination responses offer a possibility of selecting elite populations as a seed resource in S. chirayita. The Mean Germination Time (MGT) significantly declined after six months, but increased after 12 and 18 months of seed storage for the majority of plant populations. The best germination and lowest MGT occurred for seed of S. chirayita that was sown six months aft er collection, followed by slightly lower levels at 12 months. Several populations tested offer promise for the conservation of this species as potential gene bank in Sikkim Himalaya.
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(pp. 70-75)
Germination of Fresh and One Year Stored Fruits of Teak (Tectona grandis Linn. f) Collected from Several Seed Production Areas in Karnataka, South India
Rajesh P. Gunaga*, R. Vasudeva and Avinash M. Kanfade
Tectona grandis Linn. f. is a commercially important timber yielding tree species of the tropics. Teak wood commands worldwide reputation for its durability, strength, ease of working, moderate weight, beauty and dimensional stability. Hence, the areas under teak plantations are increasing rapidly and there is a greater demand for quality propagules of teak in the country. The information available on fruit germination among seed production areas (SPAs) of teak in India is limited. This study was conducted at the College of Forestry, Sirsi, South India. Fruits were collected from twenty SPAs during 2005 and 2006.

The mean germination percentage of teak fruits collected from all SPAs was significantly higher after one year of storage (43.1%) compared to germination of fresh fruits (26.2%). Significant variation was recorded among the twenty SPAs for germination of fresh fruits (10.2 to 39.8%) as well as after one year of fruit storeage (13.8 to 63.8%). Variation was also among regions for germination ranging from19 (Dandeli) to 32% (Madikeri) for freshly collected fruits and from29 (Dandeli) to 53% (Yallapur) for one year  stored fruits. This study has also shown that germination percentage was highly influenced by fruit traits such as fruit size and seed numbers per fruit and seed emptiness.
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(pp. 76-81)
A Simple Index for Describing the Efficacy of Chemicals in Breaking Seed Dormancy
Dimas Mendes Ribeiro, Frank James Araujo Pinheiro, Claudinéia Regina Pelacani, Braulio Maia de Lana Souza, Ana Maria Mapeli, Caroline Müller, Elaine Cristina Cabrini, Tales Graciano Coelho, Glayton Botelho Rocha and Raimundo Santos Barros*
When comparing the efficacy of different chemicals on seed dormancy breakage, germination percentage alone is not a good descriptor of the phenomenon because the process can be triggered by high concentrations of a compound while other compound can be highly effective under very low concentrations.

Because of that an Efficiency Index (Ief) relating the response (i.e. dormancy breakage) of dormant seeds of Townsville stylo  (Stylosanthes humilis HBK) to several selenium (Se) compounds at their optimal concentrations was employed by Pinheiro et al. (2008 b). In this paper, the index is revised to a more coherent one (Efi), that relates the effect of the chemicals on germination in a more straight-forward way. The innate dimension displayed by the new index (amount of the chemical per unit germination percentage) is an expression of the tissue sensitivity to the chemicals.
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