Volume 11, No. 2, 1987

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(pp. 103-110)
Induction of Secondary Dormancy in Seeds of Meadowfoam (Limanthes alba Benth.)
Sam Nyunt and Don F. Grabe
Fall seedings of meadowfoam (Limnathes alba Benth.) in Oregon are usually delayed until early to mid-October because of the possibility of inducing secondary dormancy from  earlier planting in warm soils. This experiment was conducted under laboratory conditions to determine if secondary dormancy is induced by warm temperatures or other environmental conditions that are unfavorable to meadowfoam seed germination.

Imbibed seeds of dormant and non-dormant lots of 'Mermaid' meadowfoam were subjected to high temperature, light and reduced oxygen treatments for 0,3,6,9,12 and 15 days. Following treatment, the seeds were removed to optimum germination conditions to assess the degree of dormancy induced by the three environmental factors. Exposure of imbibed seeds to 2S°C induced secondary dormancy in both lots after 3 days' exposure. Germination of the non-dormant lot decreased from over 90% to less than 30% after 15 days of warm temperature. Exposure to continuous light was effective in inducing dormancy after 6 days of treatment. Imbibition in an atmosphere of 2% oxygen decreased germination after 9 days' treatment. Reduction in germination by light and reduced oxygen was only moderate, but a greater degree of dormancy would be expected with longer exposure. These experiments confirmed that exposure of meadowfoam seeds to factors that inhibit germination will induce secondary dormancy after a minimum exposure period. In the field, induction of dormancy and reduced seedling emergence would be expected if soils are warm or poorly aerated. While light would be a factor in field establishment only if surface-seeded, it should be avoided in laboratory germination tests to obtain maximum germination.
Additional index words: Germination, Temperature, Light, Oxygen.
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(pp. 111-120)
Effect of Soybean Tissue Potassium Levels on Carpel and Seed Infection by Phomopsis spp. and Seed Germination1
D.M. TeKrony, D.B. Egli, and R. E. Ferriss2
The effect of potassium fertilization on seed infection by Phomopsis spp. and seed quality of four soybean (Glycine max (L.) Merr) genotypes was evaluated for four years on a soil with a low initial available potassium level. Soil potassium applications of 28 to 224 kg ha-1 significantly increased soil test potassium levels and potassium levels in the soybean leaves at growth stage R2 and in carpels at growth stages R6 and R7.

There was no significant increase in K levels of seed, however, following potassium fertilization. Soil applications of potassium had no effect on the levels of Phomopsis spp. infection of carpels at growth stages R6 and R7 or seed at harvest maturity (HM). Thus, there was no relationship between potassium concentration in carpels at growth stages R6 and R7 and Phomopsis spp. infection in carpels at R7. Similarly there was no relationship between potassium concentration in carpels at R7 or seeds at HM and seed germination or Phomopsis spp. infection of seed at HM.
Additional index words: Diaporthe phaseolorum var. sojae, fertilizer rates.
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(pp. 121-130)
Incidence of Hollow Heart of Pisum sativum on the Pacific Northwest
C.M. Rush1
Thirty-four 1984 pea cultivars and 43,1985 cultivars were evaluated for the presence of hollow heart. All cultivars had the disorder, but incidence and severity were variable.

For 1984 seedlots, percent severe hollow heart ranged from 4-75% with a mean of 30%, and for 1985 seed, the range was 5-78% with a mean of 36%. Soaking seed for 24 hr in deionized water and incubating for 6 days in damp germinating paper produced maximum symptom expression. Significantly more hollow heart developed when seed was incubated at -1/3 bar than either -1 or -3 bars. There was also more hollow heart in seed incubated at 7 C. than at 24 C. However, at 24 C. there were more rotten seed. Differences in percent severe hollow heart at various incubation temperatures could be explained by the number of rotted seed at each temperature. The development and importance of hollow heart depends on the percentage of predisposed seed and soil moisture during germination.
Additional index words: Physiological disease, Pisum sativum, seed quality, root rot, predisposition.
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(pp. 131-138)
Seed Laboratory Computerization1
A.G. Maristany and H. R. Danielson2
Seed-Lab, a software system developed at the Oregon State University Seed Testing Laboratory for managing seed laboratory information, is described. Seed-Lab shields the user from the complexities of database management by supporting menu driven inquiries.

Specifically, Seed-Lab allows inquiries about customers, accounts, invoices, plant species, types of tests, seed samples, and test results. Furthermore, Seed-Lab supports several domestic and international regulations governing the computing and reporting of seed testing results. This system runs either on a single microcomputer or on a local area network of microcomputers and is portable to any other network capable of running the Novel1 NetWare operating system.
Additional index words: seed testing; software; hardware; local area networks (LAN); personal computers.
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(pp. 139-143)
Review of the Development of Seed Pathological Testing1
J. F. Schoen2
A selective review is presented of some major historical events in the development of seed pathology with an emphasis on testing techniques. Most references are to those scientists who were members of the Association of Official Seed Analysts from the early twentieth century onward. Special recognition is given to the works of several plant pathologists at the University of Minnesota and in the Danish Institute of Seed Pathology.
Additional Index words: seed-borne disease, seed health, seed pathology.
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(pp. 144-150)
Fungi Associated With Forest Seeds in the Philippines
Sebastian S. Quiniones1
Seeds of 33 forest species belonging to 28 genera in 12 families of tropical trees were studied for health. The blotter, agar, and sand medium methods were used. The common genera of fungi found associated with the seeds were: Fusarium, Colletotrichum, Botryodiplodia, Cladosporium, Phoma, Phomopsis, Macrophoma, Cephalosporium, Aspergillus, Penicillium, Curvularia and Chaetomium. Details about their distribution and description are discussed in the text of this paper.
Additional index words: seed-borne, field contaminants, blotter and agar methods, sand medium.
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(pp. 151-157)
Changes in Structure of Pit and Antipit in Soybean Seeds and Seedling Development1
R.W. Yaklich, E.L. Vigil, and W.P. Wergin2
This study examined the fate of the pit on the abaxial surface of the cotyledon and that of the antipit on the inside surface of the seed coat. Samples of cotyledon and seed coat tissue from germinating and developing seedlings of soybean (Glycine max L. Merr.) were separated for scanning electron microscopy following initial fixation in glutaraldehyde. Holes which surrounded the antipit in seed coats of mature seeds were not observed after 1 day of imbibition.

It is possible that these holes around the antipit collapsed and closed through the force generated by the expansion of the seed coat during imbibition. By 3 days of germination, the pit on the cotyledon surface changed from a concave to convex structure. Holes that appeared on the surface of the cotyledon separate from the pit area were formed by gaps between specialized cells. Later in seedling development, the specialized cells took on the appearance of guard cells and the holes stomates. No stomates occurred on the surface of the pit. It was concluded that the above structures may have some short term function in germination and/or seedling development.
Additional index words: Glycine max (L.) Merr., cotyledon, seed coat, stomate.
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