Volume 27, No. 1, 2005

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(pp. 7-24)
The Ohio State University Seed Vigor Imaging System (SVIS) for Soybean and Corn  Seedlings
Andrew F. Hoffmaster, Lijie Xu, Kikuo Fujimura,Miller B.McDonald,* Mark A. Bennett and  Andrew F. Evans
An image processing computer application to automatically assess the vigor of three-day-old soybean [Glycine max (L.) Merrill.] and corn (Zea mays L.) seedlings was developed. The software operates on acquired digital images of soybean and corn seed lots placed on a paper towel.

Seedlings were digitally extracted away from the paper towel and converted into various digital representations. These representations were used to analyze the seedlings and segment them into normal and abnormal categories. The normal seedlings were further processed so that a one-pixel-wide summary structure of the shape of the seedling was produced. From the soybean summary structure, the software classified the seedlings into six type categories based on their shape. Each normal seedling was processed to remove the cotyledon portion of the summary structure based on the type category it fell into. The remaining summary structure,with the cotyledon removed, was then used to compute the length of each seedling in pixels. From the corn summary structure, the software first identified seeds based on their yellowish-red color, connected nearby multiple roots to the seed, and separated overlapping roots to the correct seed. Once the seedling structures were correctly identified for soybean and corn, seedling length measurements were determined. From these length measurements, speed of growth and uniformity of growth values were computed. These two values were normalized and combined into a zero to 1,000 vigor index for the soybean or corn seed lot.Combined with the post-processing corrective features, this computer software was able to achieve highly accurate and standardized measurements of each soybean and corn seedling, providing an alternative to the current method of manually measuring seedlings  for speed and uniformity of growth when performing a vigor test.
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(pp. 27--36)
Effects of Crossing Periods on Seed Maturity and Quality in a Chinese Commercial Bt Hybrid Cotton Cultivar
Hezhong Dong,* Wei Tang, Dongmei Zhang, Xiaojie Zhang and Weijiang Li
Seed (F1) of SCRC15 cotton, a commercial hybrid cultivar, was obtained by crossing a conventional line with a Bt transgenic line at five successive periods in 2001. Seeds were separated into four maturity grades using a float sink procedure and coat colors. Physical properties and seed vigor were tested in each grade. The results revealed that seed

density, kernel index and kernel/seed were significantly correlated to maturity grades, and thus could be used as important indicators of seed maturity. As seed became more mature, higher emergence and fewer diseased seedlings occurred at standard germination (30 °C) and cool germination (18 °C) temperatures. Water uptake speed and conductivity of electrolyte leakage were inversely correlated to seed maturity. Hybrid seed maturity varied with crossing periods. The percentage of immature hybrid seeds from the last crossing period was the highest, suggesting that ending hand crossing earlier than August 23 promotes higher seed quality.
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(pp. 37-48)
Retrieval and Identification of Weed Seeds from Landscape Soils
Susana H. A. C.Mogensen, Phil S. Allen* and Larry S. Jeffery
A method for recovering seeds in soils was developed in collaboration with the United  States Department of Transportation. Two approaches were considered: 1) separating seeds via wet-sieving and 2) seedling grow-out tests. Three types of samples were included: field topsoil, commercial topsoil and municipal compost.

The wet-sieving procedure used sodium hexametaphosphate to disperse soil samples. Samples were washed through a set of three sieves with decreasing mesh diameters. Seeds collected from each of the sieves were sorted by hand, identified and counted by species. For the seedling grow-out tests, soils collected from sieves and the catchment bucket, as well as unsieved soil samples, were saturated with a solution containing gibberellic acid and potassium nitrate, then kept moistened under greenhouse conditions for 28 d. Seeds of 23 weed species were found in the commercial topsoils using the wet-sieving technique, seven of which are on the Utah noxious weed list. A higher percentage of the seeds present were retrieved from smaller samples (40 cm3). Seedling grow-out tests were laborious and failed to detect as many seeds and species as the wet-sieving procedure. Results of this study suggest that screening procedures can effectively identify and quantify weed seeds in soils, but confirm that seedling grow-out tests are impractical. As experts in seed identification, seed analysts may be the ideal group to conduct soil tests on weed seeds.
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(pp. 49-58)
Observations on Seed Quality of Schinopsis balansae Engl., a Tree Species Endemic to South America
C. Alzugaray,* N.J. Carnevale, A.R. Salinas and R. Pioli
Schinopsis balansae Engl., constitutes the dominant species in the forests that occupy the Northern Santa Fe Province, Argentina. This research assesses the quality of S. balansae seeds harvested in 2000 and 2001. The seeds were evaluated 3, 12, and 18 months after harvest for viability by the tetrazolium and standard germination tests and for vigor by the germination velocity index (GVI).

Incidence of pathogens was determined in both fruits (samara) and seeds. After three months of storage at 3 °C, 77% of the seeds harvested in 2000 germinated, but only 29% germinated after 18 months. Of the seeds harvested in 2001, only 28% germinated after a 3-month cold storage period, and completely lost their viability after 18 months. Seeds tested 3 months after harvest in 2000 showed the greatest vigor index (GVI). Low quality production in 2001 appeared to be from adverse environmental conditions with poor seed quality and 55% of fruit lacking seeds. The viability and the vigor tests were good indicators of S. balansae seed quality.
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(pp. 59-65)
Gibberellin plus Norflurazon Enhance the Germination of a Dark Green Tomato Genotype
G. Ramirez-Rosales, M. A. Bennett, M.B.McDonald and D. Francis
Tomato (Lycopersicon esculentum Mill.) varieties rich in lycopene are desirable for human nutrition because it reduces risk of various cancers. Tomato genes that cause elevated lycopene content such as dark green (dg) are available. However, several genes that result in elevated lycopene also result in negative pleiotropic effects including slow germination and reduced plant height. It is uncertain whether low gibberellin levels, high abscisic acid (ABA) content or high light sensitivity account for the reduced speed of germination
of dg tomato genotypes.

This study evaluated gibberellin (GA3) and norflurazon (inhibitor of carotenoid and ABA synthesis) effects on the speed of germination of the high pigment tomato line ‘T4099’ and its recurrent parent ‘Flora-Dade’. These tomato genotypes were greenhouse-produced in summer 2001 for fruit and seed production. Seeds from mature red fruits were sown in solutions of GA3 (10–4 M), norflurazon 20 mg L–1 and norflurazon plus GA3. Speed of germination was evaluated as time to reach 50%  germination (T50) and germination index. Norflurazon alone and GA3 plus norflurazon resulted in higher speed of germination of ‘T4099’ compared to the control but not at the same level as ‘Flora-Dade’. These data suggest that the high lycopene tomato genotype ‘T4099’ produced greater levels of ABA during imbibition.
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(pp. 66-75)
Total Antioxidant Capacity of Fruit and Seeds from Normal and Enhanced Lycopene Tomato (Lycopersicon esculentum Mill.) Genotypes
G. Ramirez-Rosales,* M.Bennett, M.B.McDonald, D.Francis, and S.Contreras
Elevated antioxidant content of tomato fruits is desirable for human health and nutrition. In seeds, antioxidant capacity may also be a desirable trait for increased seed storability and slower deterioration rates. This study was conducted to test whether tomato fruits from a genotype with elevated levels of natural antioxidants produce seeds with a functionally greater total antioxidant capacity.

The tomato genotype ‘T4099,’which produces elevated levels of lycopene and ascorbic acid, and the recurrent parent ‘Flora-Dade’were grown in the field and greenhouse under standard agronomic practices. Fruits and seeds were evaluated for antioxidant capacity and lycopene content.Total antioxidant capacity of the water- and lipid-soluble fractions of seeds were evaluated using the Trolox equivalent antioxidant capacity (TEAC) and photo-induced chemiluminescence (PCL) methods. The high pigment line ‘T4099’ resulted in a higher fruit tissue lycopene content and total antioxidant capacity than ‘Flora-Dade.’However, both TEAC and PCL methods indicated that seeds of ‘T4099’ had lower antioxidant capacity and that the difference was greater for water soluble antioxidants. Based on these results, it is hypothesized that tomato fruits and seeds may compete for antioxidants. Fruits with enhanced lycopene content are desirable for human consumption, yet this may produce seeds with lower antioxidant levels and influence seed dormancy or longevity in storage.
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(pp. 76-80)
Pattern of Fruit and Seed Development in Vegetable Cowpea [Vigna unguiculata (L.) Walp ssp. sesquipedalis (L.) Verdc.]
K. Krishnakumary,* V. S. Devadas, C. Mini and T. R. Gopalakrishnan
The optimum harvest stages for cowpea [Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc.] are critical to the vegetable market, as well as quality seed production. Pods of ‘Lola’ cowpea were harvested at two day intervals from 2 to 24 days after anthesis to measure pod and seed characteristics. Fruit and seed maturation occurred in two phases.

The pod length and pod weight reached maximum at 12 days after anthesis, which is considered the optimum harvest stage for vegetable use. The maximum germination and vigor index was observed in seeds from pods harvested at 18 days after anthesis, which is considered as physiological maturity and the optimum stage to harvest for use as seed.
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(pp. 81-88)
Effect of Harvest Maturity and Drying Method on Okra Seed Quality
I. Demir* and S. Ermis
The effect of seed maturity at harvest and slow and fast drying methods on okra [Abelmoschus esculentus (L).Moench.] germination and seed vigor were studied. Fruits were harvested 25, 30, 35, 40 and 45 days after anthesis (DAA) in 2002 and 2003 and seeds were either threshed immediately after harvest and dried at 20 °C for 72 hours (fast drying method) or allowed to remain in the fruits for 10 days at 20 ± 2 °C, then threshed and dried (slow drying method). Seed quality at each stage was assessed by

speed of radicle protrusion, standard germination, 5-day germination count, accelerated aging test and seedling emergence percentages along with changes in seed color,moisture and weight. Initial seed moisture content varied between 66.0 and 13.6% and 62.7 and 14.8% in harvests of 2002 and 2003, respectively.Maximum seed dry weight (57–60 mg/seed) occurred at 30 DAA regardless of the drying method used. Maximum standard germination, 5-day germination count and seedling emergence percentages occurred at 30 DAA and coincided with maximum seed dry weight when seeds were slow dried within the fruit, but occurred 10–15 days later (40–45 DAA) if they were threshed and dried immediately after harvest. Results showed that threshing okra seeds following slow drying in the fruits increased seed weight in early harvest and improved seed quality at maturity.
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(pp. 89-94)
Methods for Extraction and Amplification of DNA from Soybean Seed
Melvin D. Bolton, Berlin D. Nelson,* Robert B. Sparks, and Adi Santoso
Extraction and amplification of plant DNA is an integral part of using molecular technology for crop improvement such as in molecular marker assisted selection (MAS). In soybean [Glycine max (L.) Merr.], leaves are generally the tissue of choice for DNA extraction. A comparison was made between using standard leaf extracted DNA and seed extracted DNA while utilizing a marker-assisted selection protocol to detect resistance to

Heterodera glycines Ichinohe, the soybean cyst nematode (SCN) and Phytophthora sojae Kaufm. & Gerd., the cause of Phytophthora root rot. The protocol was unsuccessful using seeds, thus experiments were conducted to determine modifications that would allow seeds as the DNA source. The resulting procedure consisted of extracting DNA from seed radicles and using a disk based DNA purification system. The DNA was amplified with polymerase chain reaction (PCR) using microsatellite primers Satt309 and Sat_168 to detect the rhg 1 SCN resistance gene and Satt 159 and Satt 152 to detect the Rps 1 Phytophthora resistance gene. The resulting product was diluted 1:100 in TE buffer and 1 μl aliquot was reamplified and then electrophoresed in an agarose gel. A second protocol was developed by changing PCR conditions of the standard leaf DNA protocol to use undiluted DNA extract. These protocols from DNA extraction to gel completion are easy to conduct and can be completed in about 7 to 9 hours. Both protocols resulted in consistent visualization of microsatellite markers for resistance to both H. glycines and P.sojae and were equal to the results using leaf tissue as the DNA source. Using seeds instead of leaves  as the DNA source can simplify MAS protocols.
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(pp. 97-100)
Detection of Phomopsis longicolla T.W. Hobbs and its Pathogenicity on Glycine max (L.) Merr. and Weed Hosts
Alemu Mengistu* and Krishna N. Reddy
Greenhouse and laboratory studies were conducted in 2002 to detect the presence of Phomopsis sp. in weed species that may be associated with reducing soybean [Glycine max (L.) Merr.] seed quality. Phomopsis longicolla T.W. Hobbs, the fungal pathogen responsible for soybean seed decay, was recovered from previously unreported asymptomatic weed species.

  P. longicolla was recovered from eclipta, prickly sida, Illinois bundleflower, Texasweed, prostrate knotweed, pitted morning glory, nodding spurge, and slender aster found in nearby soybean field. The isolates from weed species were used to inoculate greenhouse-grown weeds and soybean. The P. longicolla recovered from eclipta and nodding spurge were the most aggressive and were as pathogenic as the soybean isolate. Sicklepod and palmleaf morningglory were included in the test and were severely infected by the isolates from eclipta, nodding spurge, and soybean. These results indicate the potential existence of pathogen variability within P. longicolla and these weed species  may serve as symptomless carriers and source of inoculum which may result in reduced soybean seed quality.
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(pp. 101-103)
A Modified Chromosome Squash Technique to Determine Mitotic Activity in Primed Mericarps

Michael W. Olszewski,Wallace G. Pill,* and Thompson D. Pizzolato
Mericarps of ‘Moss Curled’ parsley (Petroselinum crispum Mill. Nym. ex A.W. Hill) were hydroprimed (1 or 3 days in water at 20 °C) or osmotically primed in polyethylene glycol (–1.0 MPa for 7 or 21 days at 20 °C). Extracted whole embryos then were subjected to a modified chromosome squash technique which sequentially involved fixing, staining, tissue squashing, and chromosomal viewing.

The technique quantified relative embryonic mitotic activity. The number of cells per embryo with late anaphase activity was greatest for 3 day hydroprimed mericarps (15), then 7 or 21 day osmotic primed mericarps (3), with 1 day hydroprimed mericarps showing no mitotic activity.
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(pp. 104-107)
Phenotypic Traits of Genetic Twins in Coconut Palm (Cocos nucifera L.)and Their Utility in Seed Production
V. Arunachalam
Genetic identity is important in seed production of such sexually propagated, cross-fertilized, heterozygous crops as coconut palm (Cocos nucifera L.), which are exclusively propagated by seeds. Due to their uniform nature, twins are used in genetic studies, breeding and to determine identity.

The objective was to identify uniform phenotypic traits within twins for use in determining genetic identity. Phenotypic correlation was determined among twin pairs for 11 important foliar traits in coconut. Of the traits under study, leaf sheath fiber thickness, petiole length and number of leaflets had high correlation and are either highly heritable or have adaptive significance. These traits have  practical applications in seed production and breeding.
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(pp. 108-112)
Effect of Accelerated Aging on Seed Germination of Oil Palm (Elaeis guineensis Jacq. var. dura Becc.)
P.Murugesan,* R. K.Mathur, R. S. N. Pillai, and M. Kochu Babu
Oil palm, Elaeis guineensis Jacq., seed is dormant when harvested and, under natural conditions, germinates sporadically over several years. A method to break dormancy would be beneficial to commercial seed production and the timely supply of planting material. Hence, this investigation evaluated seed germination by using accelerated aging to break dormancy in fresh oil palm seed.

Changes in seed moisture content during ambient storage and accelerated aging (AA) were documented. Accelerated aging was performed according to the Seed Vigor Testing Handbook of the Association of Official  Seed Analysts. One sub-sample was AA treated without initial water soaking and another was presoaked for five days prior to the AA test. An unaged control sample was maintained under ambient storage conditions at 35 °C in closed polyethylene bags. Seed were tested for germination and moisture content following AA treatment at ten day intervals over 120 days. Moisture content of the control was found to decrease over the 120 day storage period; whereas, aged seeds maintained uniformly high moisture content. Aged oil palm seeds exhibited significantly improved germination capacity compared to un-aged seeds. It was noteworthy that presoaked AA treated seeds recorded 40, 72 and 80% germination after 50, 60 and 70 days; whereas, unaged seeds had no germination during the same period. Furthermore, the five day presoak followed by aging treatment significantly improved germination.
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(pp. 115-120)
Evaluating Rice (Oryza sativa L.) Seed Vigor
Amanda L. Patin* and Tim J. Gutormson
Standard germination is typically the only laboratory bioassay performed on rice (Oryza sativa L.) seed. Currently, no suggested or recommended procedures for conducting rice seed vigor tests are available in the handbooks on vigor testing from the International Seed Testing Association (ISTA) or the Association of Official Seed Analysts (AOSA). In April, 2003, a study was conducted on ten lots to examine possible vigor tests for rice seed.

The tests that were performed are 1) standard germination, 2) sand germination, 3) cold germination, 4) cool germination, 5) accelerated aging, 6) saturated cold and 7) bulk electrical conductivity. The standard and sand germination methods provided the highest germination percentages, followed by the cold, accelerated aging, saturated cold and cool test methods. The results obtained for both the cool and electrical conductivity tests indicated that the test parameters need adjustment to separate lots with differing vigor levels. The cold and accelerated aging test methods discriminated between samples withlower seed vigor and those with high standard germination percentages. Additional studies should include more seed lots and laboratory results should be compared to actual field emergence to further evaluate the cold and accelerated aging methods for assay of rice seed vigor.
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(pp. 121-126)
Evaluating Peanut (Arachis hypogaea L.) Seed Vigor
Wayne R. Guerke
Production of seed peanuts requires careful management of several factors that may affect quality, for example, adequate water and calcium availability during pod-fill, maturity at harvest, curing and storage at the recommended temperature and seed moisture levels, and shelling and conditioning with minimal mechanical damage. Seed vigor tests may be used to assess storability and suitability for planting. Tests may be categorized as quick tests, which can be performed within 24 hours, and standard germination and stress-type germination tests, which require 7 to 12 days. 

Calcium assay is included as a quick method to assess quality since it is a critical nutrient for seed peanuts. The tetrazolium and electrical conductivity tests both evaluate aspects of tissue integrity. The standard germination test is indicative of seed vigor with > 85% germination considered strong vigor. The accelerated aging and cold germination tests are two  stress-type methods that are good indicators of seed strength. The accelerated aging procedure has been well documented for use on a number of crops and it provides good reliability when procedures are closely adhered to; however, it does not apply well to high volume laboratory testing. The cold germination test is well suited to high volume testing when performed parallel with the standard germination test. Since these various testing methods evaluate different parameters of seed vigor, it is recommended that a combination of calcium assay, standard germination test and stress-type vigor test provides the best management information for seed peanuts.
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(pp. 127-129)
Cool Germination Test: Principles and Applications In Cotton
Bryan R. Savoy
The cool germination test is the most widely used measure of seed vigor in the USA to evaluate cotton (Gossypium hirsutum L.) planting-seed quality. The purposes of this test are to rank seed lots and to determine if seed lots are suitable for planting in cool soils or less than ideal situations. The cool germination test is

conducted on 200 seeds (four replicates x 50 seeds each) in rolled towels at an 18 °C constant temperature. Rolled towels are placed upright and incubated for seven days. On the seventh day, a single final count is made. Normal seedlings are defined as those having a combined radicle + hypocotyl length of four cm or longer. It is critical that the average temperature is maintained at 18 °C with no more than ± 0.3 °C fluctuation for the duration of this test. Seed lots with greater than 60% cool test values are considered good to excellent. A vigor index based on a combination of cool and standard germination test results is a good predictor of field emergence. Freshly harvested cottonseeds can be physiologically dormant or hard seeded,resulting in low cool test scores from slow seedling growth or restricted imbibition. As a result, caution must be used when interpreting low-test scores in newly harvested seeds. The cool germination test is a reliable predictor for the quality of both weather deteriorated new crop seed and carryover seed.
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(pp. 130-134)
Cottonseed Vigor Tests (excluding the Cool Germination Test)
Paul G. Johnson
Effective management of cottonseed requires assessment of a number of quality factors to determine storability and suitability for planting. The seedling growth test, free fatty acid test and cutting test, which assay physiological, biochemical and physical parameters of cottonseed quality, respectively, are probably the three most routinely used procedures other than the cotton cool test.

The seedling growth test evaluates seedling vigor during the early days of the germination test, hence it can be performed very cost effectively. The free fatty acid test assays cottonseed oil quality and is commonly used on bulk cottonseed. The cutting test evaluates seed maturity in bulk cottonseed as a measure of quality by examining the condition and color of the seed embryo. These procedures are used to determine seed quality following harvest, but they may also be used over time to monitor seed during storage and conditioning, plus prior to marketing and planting.
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(pp. 135-146)
Accelerated Aging Test: Principles and Procedures
Dennis M. TeKrony
The accelerated aging (AA) test exposes seeds for short periods to two environmental variables, high temperature and high relative humidity, which cause rapid seed deterioration. High vigor seed lots will withstand these stressful conditions, deteriorate at a slower rate and have high germination following aging, compared to low vigor seed lots. This paper reviews the major factors influencing the AA test results and provides a stepwise procedure for conducting the test.

The essential equipment needed for the AA test is outlined and the primary questions relating to standardization of this test are answered. The results of the AA test have been shown to provide an accurate estimate of seed vigor in soybean, corn and many other crop species. Several studies have reported that AA results more accurately predict field emergence under stressful soil conditions than do standard germination results. The AA test for soybean is recommended by the Seed Vigor Testing committees of both the Association of Official Seed Analysts and International Seed Testing Association (ISTA). The AA test has met the ISTA requirements for repeatability and standardization and was approved in 2001 for the International Rules for Seed Testing as an accepted vigor test for soybean seed.
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(pp. 147-154)
Evaluating Sorghum Seed Vigor
J. S. Burris
Sorghum [Sorghum bicolor (L.) Monench] seed is often tested for vigor in addition to the standard germination test. Often the same tests that are used for hybrid maize are used for sorghum. The range in correlation between these tests and field performance is varied and depends upon the stress level present in the field. The causes of the vigor differences in sorghum are similar to those of other crops; however, evaluating vigor in sorghum can be confounded by the presence of a transient dormancy.

Further, sorghum has, in general, received less total research than maize. Some data suggests that traditional laboratory seedling vigor tests used for other crops may not apply as well to sorghum. Genetic influence on seedling vigor appears to be a potential area for breeders to screen cultivars as well as for laboratory applications to predict seedling vigor. Factors such as seed size, membrane integrity and response to seed maturation temperature impact the resultant sorghum seed vigor. Since mitochondria are sensitive to stresses in the production environment and receive maternally inherited qualities, this may be an area that could be developed for laboratory evaluation of sorghum seed vigor. High vigor seed possess an abundant supply of intact and protected mitochondria which upon imbibition are able to immediately begin oxidative phosphorylation and generate the energy needed to support growth and development.
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(pp. 157-160)
Using SSR as an Alternative to Isozyme for Corn Hybrid Purity Testing
Huabang Chen,* Pam Hogue, Karen Miller, Alan Galbreth, and Rick Vierling
The feasibility of using simple sequence repeat (SSR) DNA markers as an alternative to isozymes for testing hybrid purity in corn was assessed. SSR markers have the advantage of being abundant and distributed throughout the maize genome; whereas isozymes in corn have limited value for separating offtypes due to their relatively low numbers, poor polymorphism, plus the method has low throughput.

Most SSR markers are co-dominant, single copy and polymorphic among corn inbred lines. PCR multiplexing of SSR markers makes it possible to simultaneously use more SSR markers to assess corn hybrid purity. This approach maximizes efficiency by increasing throughput and decreasing costs. SSR markers are amplified from genomic DNA extracted directly from single dry seeds compared with isozymes for electrophoresis that are extracted from 10-day-old seedlings.
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(pp. 161-166)
Germination and Stand Establishment of Polymer Coated Canola (Brassica napus L.) Seeds Subjected to Moisture Stress and Various Planting Depths and Soils
Udai R. Bishnoi* and James Wilhite
Several environmental conditions, including soil type, soil moisture and planting depth, affect stand establishment of winter canola (Brassica napus L.). The use of polymer coating on other crops has been reported to improve plantability. Therefore, the effects of three polymers (Spectrum Series 100, Spectrum Series 500 and SB 2000) coated on canola seed with three concentrations (0.25, 0.50 and 1.00%) were evaluated

in comparison to uncoated seed (control) for standard germination, germination at three moisture stress levels (–0.3, –0.5, –0.7 MPa) and seedling establishment from 0.5 and 1 inch depth in sandy, silt, and clay loam soils. Results showed that all polymers decreased germination significantly and polymer SB 2000 had a greater negative effect than Spectrum Series 100 and 500. Decrease in moisture potential and increase in polymer concentration further decreased germination. Spectrum Series 100 at 0.50% and Spectrum Series 500 at 1.00% concentration increased stand establishment at 0.5 in depth compared to 1 in depth in all three soil types. The results of the study suggest that polymer coating can be used to slow down germination and to estimate actual field stand establishment.
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