Volume 33, No. 2, 2011

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Download Abstracts from oral and poster presentations given at the 101st Association of Official Seed Analysts and the 88th Society of Commercial Seed Technologists (AOSA/SCST) annual meeting held in Williamsburg, Virginia on June 7–10, 2011

(pp. 79-87)
Propagation of Vanda coerulea Via In Vitro Asymbiotic Seed Germination
Viki Manners, Suman Kumaria* and Pramod Tandon
An efficient method of propagation for Vanda coerulea, a rare and endangered species, was developed via in vitro asymbiotic germination of seeds. Seeds excised from 10 to 11-month old artificially pollinated capsules were cultured aseptically on different media. 

A  maximum seed germination of 71.8% was recorded on Murashige and Skoog (MS) medium devoid of plant growth regulators. However, incorporation of either 5 μM 6-benzyl amino - purine (BAP) or 5 μM indole 3-acetic acid (IAA) separately in the MS medium further enhanced seed germination to 94.4% and 92.6%, respectively. A maximum shoot number of 13.2 with an average of 5.1 roots was obtained on MS medium supplemented with a combination of 5 μM BAP and 15 μM IAA. Well developed seedlings of V. coerulea were  hardened in a potting medium comprised of charcoal, brick pieces and decaying litter in a 1:1:1 ratio, with a top layer of moss, wherein 91.2% survivability was obtained.
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(pp. 88-110)
Effect of Alternative Disinfection Treatments Against Fungal Canker in Seeds of Pinus radiata
Eugenia Iturritxa,* Marie Laure Desprez-Loustau, Ignacio García-Serna, Eneka Quintana, Nebai Mesanza and Jennifer Aitken
Seeds and seedlings of Pinus radiata may be seriously damaged by the canker fungi Diplodia pinea and Fusarium circinatum. This study evaluated alternative seed disinfection treatments against these canker fungi. Experiments were conducted to determine both inhibitory and fungicide effects on colony growth of D. pinea and F. circinatum.

Treatments  included 24 chemicals at four doses of 1, 10, 100 and 1000 μg mL−1, eight essential oils at
five dilutions of 10, 25, 50, 75 and 100% v/v, two antagonistic organisms, Trichoderma harzianum and Trichoderma harzianum, from Basque Country plantations, and four thermotherapy treatments of 55 °C for 8, 9, 10 and 11 hours in vitro. Fungicide and  fungistatic effects on inhibition of fungal colony growth were evaluated and phytotoxicity of treatments on P. radiata seeds analyzed. Fusarium circinatum and D. pinea responded in similar ways to the tested treatments, although D. pinea was often inhibited at lower doses of chemical fungicides and higher doses of essential oils. Thermotherapy and Trichoderma treatments showed greater effectiveness against the D. pinea strain than the F. circinatum strain. Germination of P. radiata seeds was highly affected by essential oils application, causing a strong inhibitory effect (≥ 92.25% germination inhibition) with most of the tested oils.
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(pp. 111-121)
Evaluation of Morphological Variation of Common Bean Seeds Through Image Analysis
Juhi Mishra, Vikash Singh Jadon, Manju P. Gusain and Aradhana*
Measurement of various morphological traits of common bean seeds and grouping of landraces collected from Uttarakhand was carried out using image analysis. Projected area, perimeter, major diameter, minor diameter and color of seeds were measured using image analysis.

Colors were expressed in terms of RGB channels (red, green and blue) and HSL channels (hue, saturation and lightness). Images of 50–100 seeds per landrace in three replicates were captured. All image analysis was carried out using ImageJ, a Java based, multithreaded, freeware image processing and analysis program. Weight of 100 seeds was also taken into account. All data were subjected to principal component analysis, where 90.9% of the variability was expressed and used to group landraces into clusters. Clusters were further refined by hierarchical clustering using the Unweighted Pair Group Method with Arithmetic Mean (UPGMA), and the resulting dendrogram with cophenetic correlation coefficient of 0.97 grouped 26 landraces into four clusters. Analysis of variance revealed  that only the color feature significantly discriminates these landraces.
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(pp. 122-133)
Variability in Soybean Seed Counts Determined by Electronic and Manual Methods
H. Liu, L.O. Copeland and S.G. Elias*
The soybean [Glycine max (L.) Merr.] seed count test is routinely conducted to achieve desired field planting rates. Over or under-seeding affects seed production systems adversely. This study was conducted to establish meaningful tolerances that can be used for truth-in-labeling purposes.

Experiments were conducted to 1) measure seed count variation among and within laboratories, 2) assess the effect of bag to bag variation within a seed lot on seed count tests, 3) measure the impact of seed moisture content on seed counts, 4) compare electronic versus manual seed count methods, and 5) determine the effect of sample size and number of replications on test variability in order to establish appropriate tolerances for seed count tests. Eight soybean seed lots were used by 42 laboratories over a three-year period to test the above variables. Results showed that including outlier test results (extreme values) contributed to variation in seed count tests within and among laboratories. Heterogeneity from bag to bag within a seed lot was significant and should be considered in establishing tolerances. Adjusting moisture content of seeds to a uniform level increased seed count test variation. Electronic and manual seed count methods produced comparable results. Sample size was more important than number of replicates per test. A 3.1% tolerance value was recommended as the largest insignificant difference between two test results. In case of lot heterogeneity, tolerances of 4.5 to 5% should be considered.
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(pp. 134-146)
Thermotolerance Classification of Ornamental Pepper Cultivars Using Seed Germination  Traits
Bandara Gajanayake, Brian W. Trader, K. Raja Reddy* and Richard L. Harkess
Fluctuating and extreme changes in temperature during seed germination may disrupt several physiological processes. Developing easy and reliable screening techniques to identify cultivar tolerance to extreme temperatures would benefit crop breeding programs in selecting cultivars for niche environments. An experiment was conducted to study the influence of temperature on 12 ornamental pepper cultivars using in vitro seed germination parameters.

Time-series seed germination responses at a range of temperatures from 10 to 45 °C with 5 °C increments were carried out and number of germinated seed recorded every six hours. Seed germination rate (SGR) and maximum seed germination (MSG) were derived from temperature and germination timecourse data by fitting a three-parameter sigmoidal function. Quadratic and bi linear functions best described SGR- and MSG-temperature response functions, respectively. Cumulative temperature response indices (CTRI) of each cultivar, calculated as the sum of eight individual temperature response indices derived from temperature adaptability range (TAR = Tmax to Tmin), Tmin, Topt, and Tmax, for SGR and MSG, were used to classify cultivars for temperature tolerance. Cultivars were classified based on CTRI(heat) as heat tolerant (‘Medusa’ and ‘Treasures Red’), heat intermediate (‘Thai Hot’, ‘Variegata’, and ‘Red Missile’), and heat sensitive (‘Purple Flash’, ‘Salsa Yellow’, ‘Black Pearl’, ‘Chilly Chili’, ‘Explosive Ember’, ‘Calico’, and ‘Sangria’). Similarly, cultivars were classified for cold tolerance as cold sensitive, moderately cold sensitive, moderately cold tolerant and cold tolerant based on CTRI(cold). Screening based on seed germination parameters is a simple and inexpensive method for determining vegetative temperature tolerance in pepper breeding programs.
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(pp. 147-154)
Dormancy Breaking in Jute Mallow (Corchorus olitorius) Seeds
Faith N.W. Maina*, Reuben M. Muasya and Linnet S. Gohole
Jute mallow (Corchorus olitorius L.) is an important African leafy vegetable in Kenya. It is highly nutritious and has commercial importance. Jute mallow seeds exhibit dormancy, reducing seed germination and adversely affecting field performance, but limited research has been done on appropriate dormancy breaking methods. In this study, efficacy of various dormancy breaking methods was tested. Treatments included mechanical scarification, soaking in boiling water for 5 min, leaching, soaking in water for 24 h at room temperature, applying wood ash paste on the seeds, soaking in 1% KNO3 for 1 min, and a control. Analysis of variance and Scheffe’s multiple comparison procedure were used to identify methods that significantly differed in seed germination from the control. The most effective treatment was mechanical scarification, followed by leaching and lastly soaking in hot water. The rest of the methods did not significantly differ from the control.
It is therefore recommended that farmers use mechanical scarification to break dormancy in jute mallow seeds before sowing.

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Carbon Nanotubes Can Promote Seed Germination via Seed Coat Penetration
Ali Pourkhaloee, Maryam Haghighi*, Mohammad Jamal Saharkhiz, Hadi Jouzi and Mohammad Mahdi Doroodmand
Some nanoparticles, like carbon nanotubes, can significantly change plant cell morphology and physiology. The effects of single-walled carbon nanotubes (SWCNT) on seed germination and seedling growth of salvia (Salvia macrosiphon Boiss.), pepper (Capsicum annuum L.), and tall fescue (Festuca arundinacea Schreb.) were studied at four concentrations (10, 20, 30, and 40 mg L−1) plus a control (0 mg L−1) under laboratory and greenhouse conditions.

In the laboratory, application of SWCNT increased germination percentage compared to the control. The highest germination percentages for salvia, pepper and tall fescue were 59.6%, 92.9% and 72.9%, respectively. The best effect on seedling length was observed at 10 mg L−1 of SWCNT for salvia and pepper, and at 40 mg L−1 for tall fescue. In the greenhouse, 30 mg L−1 of SWCNT led to the greatest seedling length. In laboratory and greenhouse studies, 10, 20, and 30 mg L−1 of SWCNT had the most pronounced effects on seedling fresh and dry weights compared to the control. For most measured parameters, the highest concentration of SWCNT was associated with negative effects. Overall, the best seed germination and seedling growth for salvia and tall fescue were achieved at 30 mg L−1 of SWCNT, and at 10 mg L−1 for pepper.
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(pp. 173-181)
Variation in Seed Soluble Proteins, Carbohydrates, Free Amino Acids and Germination of Three Garhwal Himalayan Conifer Species
B.S. Rawat and A.K. Uniyal*
Seed biochemical composition (protein, sugar, starch and free amino acid content) and percentage germination in seed lots of three important conifer species, Abies pindrow, Cupressus torulosa and Picea smithiana from Garhwal Himalaya, revealed significant differences among these species. The highest protein (30.41 mg g−1), starch (72.96 mg g−1) and free amino acid (5.512 mg g−1) contents were found in seeds of A. pindrow, maximum sugar content (71.78 mg g−1) in C. torulosa, whereas the highest germination (72%) was observed in P. smithiana seeds from Tapovan provenance.

On the other hand, the lowest protein (8.51 mg g−1) and free amino acid (0.62 mg g−1) contents were found in seeds of C. torulosa, and sugar (2.68 mg g−1) and starch (0.86 mg g−1) contents in P. smithiana and minimum germination (34%) was observed in A. pindrow. Correlation studies suggested that there were no significant associations between altitude and any of the tested seed biochemical constituents. Additionally, no significant correlations were established between and among the different biochemical constituents, as well as germination, for all three species. Thus, exploiting natural variation and usingappropriate seed accessions as planting material could be promising tools for large scale multiplication of these  potentially useful conifer species.
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(pp. 182-190)
Effect of Different Static Electromagnetic Fields on Germination Speed of Mung Beans (Vigna radiata var. radiata)
E. Rajasekhar, M. Nagaraju*, S. Raisa Reshma and R. Jeevan Kumar
This study investigated the influence of static electromagnetic fields on speed of seed germination of mung beans (green beans), measured as the number of germinated seeds after 24 h of incubation. Prior to germination, seeds were exposed to different types of electromagnetic fields (EMF), namely Helmholtz, north pole and south pole, and different field strengths of 5, 10, 30 and 60 millitesla (mT) at exposures of 15, 30, 45 and 60 min.

Results indicated that speed of germination improved following exposure to south pole EMF compared to the control and the other two field types. Upon increasing field strength up to 10 mT, speed of germination improved, but decreased at higher field strengths. Increasing exposure period up to 45 min also led to improved speed of germination. The highest speed of germination was observed using a south pole EMF at 10 mT and an exposure period of 45 min.
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(pp. 191-196)
Seed Vigor Imaging System for Two-Day-Old Corn Seedling Evaluation
V.H.V. Mondo, M.A.N. Dias* and M.B. McDonald
Vigor testing is an important determinant of seed quality, providing supplementary information to a germination test. The objective of this study was to compare a 2-day-old seedling test for corn seed vigor assessment using the seed vigor imaging system (SVIS®) to other established vigor tests.

Six maize (Zea mays L.) seed lots were evaluated for water content, germination and vigor using various tests including seedling emergence, accelerated aging, cold test and SVIS®. The 2-day-old SVIS® test produced similar results to the other vigor tests, including the 3-day-old SVIS® seedling test. Analysis of vigor index data for 2-day-old seedlings showed similar results to the 3-day-old seedlings and the other tests, and was sensitive enough to provide additional seed quality information along with germination test values. Based on these findings, the 2-day-old maize seedling vigor test using SVIS® was an improved method for vigor testing; it was more rapid and required fewer resources than other vigor tests for this important crop.
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