Volume 33, No. 1, 2011

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(pp. 7-21)
Occurrence and Trends of Weed Seed Contaminants in Fine Fescue Seed Lots in Oregon
Steve C. Alderman,* Sabry G. Elias, Andrew G. Hulting
Fine fescues are highly valued cool-season turf species. Nearly all of the fine fescue seed grown in the United States is produced in Oregon, although little is known about the occurrence of weed seed contaminants in these seed lots. This study was conducted to assess the diversity and frequency of occurrence of weed seed in chewings (Festuca rubra subsp. commutata), creeping red (Festuca rubra subsp. rubra), and hard fescue (Festuca trachyphylla) samples submitted to the Oregon State University Seed Laboratory.

The samples represent seed lots from seed production fields. Weed seed data from 1986–1995 and 2002–2006 were collected from the purity analysis reports of certified seed samples of chewings, creeping red and hard fescue. Ninety-five weed seed contaminants were  identified to species, with an additional 30 identified to genus. No weed seeds  contaminants were found in 30% to 50% of the seed lots, depending on the year. Typically, fewer than three different weed species were detected within a sample. The most common
contaminants, occurring annually, were rattail fescue (Vulpia myuros), annual bluegrass (Poa annua), and downy brome (Bromus tectorum). Among these, rattail fescue was the most common, occurring in 30% to 61% of seed samples, depending on the year. The number of weed species varied among years and increased as the number of seed lots tested per year increased. During the past decade, the number of new weed species contaminants detected increased at a rate of approximately three per year.
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(pp. 22-28)
Container Material and Chemical Treatment Affect Storage of Quality Protein Maize (QPM)  Seeds
J.A. Adetumbi,* S.A. Olakojo and M.O. Ajala
Vulnerability of Quality Protein Maize (QPM) genotypes to storage pests in tropical agro-environments is of major concern. The effects of storage container materials (brown paper, polyethylene and hessian bags) and storage chemicals [aluminum phosphide (Forcetoxin™), pirimiphos-methyl (Actel lic 25 EC™) and thiamethoxam + metalaxyl-M + difenoconazole (Apron Star™)] on seed quality of some newly developed QPM varieties were evaluated to determine options that will preserve seed quality under conditioned storage.

Seeds were evaluated after six months of storage for seed appearance,
damage, viability loss and insect population counts. Results showed that storage materials, chemicals and varieties tested were significant for all the parameters tested. Quality Protein Maize seeds stored in paper bags were better in terms of appearance rating, seed damage and insect count but recorded highest viability loss. Similarly, Apron Star preserved seeds against insect pests better than other storage chemicals but was harsh on the viability of the seed. Among the QPM varieties tested, storability of ART/98/SW1 was similar to field corn and was recommended to be used to improve seed storage characteristics of other QPM varieties.
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(pp. 29-39)
Quality and Germination of Maytenus vitis-idaea Seeds
N.J. Carnevale, C. Alzugaray* and A.R. Salinas
The goals of this work were to study the physiological quality and germination requirements of Maytenus vitis-idaea seeds, and determine the effects of salinity on seed germination and vigor. Maytenus vitis-idaea is a shrub, 2 to 5 m high, of the Celastraceae family and a typical species of the Chaco region of Argentina.

Seeds were collected in the Experimental Station of Ministry Dr. Tito Livio Copa in Las Gamas, city of Vera, Santa Fe Province, Argentina, dried and stored at 3 °C. Purity analyses were performed, 1000-seed weight and moisture content were determined. Vigor, tetra zolium viability and germination tests were done under normal and saline conditions. Maytenus vitis-idaea seeds did not require pre-treatments for germination and could be stored for a relatively long period. The species is moderately sensitive to high salinity and drought stress and can therefore develop in places that glycophytes do not tolerate. It is possible to use it for the restoration of degraded sites, including areas with highly saline soils, such as severely degraded sites (peladales), and areas with naturally high salinity.
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(pp. 40-52)
Comparative Germination and Seedling Growth Response to Drought and Salt Stresses in a Set of Safflower (Carthamus tinctorius) Varieties
Lamyae Zraibi, Abdelghani Nabloussi,*  Miloud Kajeiou, Ahmed Elamrani, Ahmed Khalid and Hana Serghini Caid
Soil salinization and drought co-occur frequently in nature, but there is little information on the comparative effects of salt and water stresses on crops, and particularly on safflower. In this research, we investigated the comparative response of seed germination and seedling growth, two crucial stages of plant establishment, of different safflower (Carthamus tinctorius) varieties to salt and water stresses, determining factors responsible for stress inhibition in relation to salt toxicity and osmotic effect.

Four varieties were evaluated during germination and seedling growth under salinity and drought conditions induced, respectively, by NaCl and PEG-6000 solutions, at the same water potentials (0 to −900 kPa). Parameters measured were germination percentage, germination rate, mean germination time, and root and shoot length. Results showed significant differences among varieties and solution concentrations for all parameters. Although germination was delayed in both solutions, it continued at all concentrations of NaCl but ceased at −250 kPa of PEG. At equivalent water potentials, NaCl had a lower inhibitory effect than PEG on germination and seedling growth, indicating that the inhibition of germination resulted from osmotic effect rather than salt toxicity. Root and shoot length should be more effective selection criteria for salt tolerance than germination percentage, because salt stress had a less pronounced effect on the latter. Further research at the adult stage is needed to confirm the tolerance of some varieties to both stresses and compare the effects of NaCl and PEG on other growth attributes.
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(pp. 55-62)
Treatments to Improve Germination of Prosopis kuntzei
Sandra Bravo,* Roxana Abdala, Fidelina Abraham and Marta Pece
The objective of this work was to evaluate seed coat physical treatments and different substrates on germination of Prosopis kuntzei. Physical treatments included seed coat nicking, mechanical scarification, room temperature water soaking and soaking in boiling water followed by cooling to room temperature. Treated and control seeds were sown on paper towels and sterile river sand.

Normal and abnormal seedlings, number of dead seeds and number of hard seeds were recorded. Although mechanical scarification, nicking and room temperature soaking followed by sowing on sand tended to increase germination and number of normal seedlings, there was no significant improvement over the control. Boiling temperature water soaking was the only pretreatment resulting in high germination and normal seedlings on paper. Number of abnormal seedlings was higher in the control, room temperature water soaking, mechanical scarification and nicking treatments sown on paper compared to the same treatments in sand, indicating an unfavorable effect of the first substrate. Hard seed percentage was highest in the control and water soaking treatments followed by sowing on sand, suggesting a probable effect of substrate moisture content. Results suggest that mechanical scarification, nicking and both types of water soaking increase germination of P. kuntzei, and that type and initial moisture content of substrate affects the number of dead and hard seeds and the number of abnormal seedlings. These results should contribute to improving germination practices, leading to production of high quality P. kuntzei seedlings.
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