Improving the Germination of Johnsongrass Seeds
Kar-Ling J. Tao1
Eight seed lots of Johnsongrass had a mean germination of 46% after a 35-day standard germination. The tetrazolium tests, however, indicated a mean germination potential of 71% for these eight seed lots. A 30-min scarification with sulfuric acid (95-98% ) induced nearly complete germination within 10 days.
Additional index words: Sorghum halepense, Acid scarification.
Germination Responses of Sweetclover Seed to Infrared, Radiofrequency, and Gas-Plasma Electrical Treatments1
S . O. Nelson, L. E. Stetson, D. W. Works, and C. A. Pettibone2
Six nonscarified seed lots of sweetclover, Melilotus of ficinalis Lam., and M. alba Medik., were exposed to infrared radiation, radiofrequency electric fields, and gas-plasma radiation to compare the effectiveness of the treatments in reducing hard-seed content. All three treatments were about equally effective. Significant increases in normal-seedling germination and corresponding decreases in hard-seed percentages were achieved, but substantial amounts of hard seed remained in all seed lots after treatment.
Additional index words: seed treatment, hard seed, infrared radiation, dielectric heating, gas-plasma radiation, seed storage.
CASAS (Computerized Automated Seed Analysis System): An Approach to the Analysis of Testing Seed1
A computerized automated seed analysis system (CASAS) has been developed which enables an analyst to estimate physiological parameters of seed and compare the values obtained with standards for seed of known quality. The system classifies the sample as commercially acceptable or substandard, based upon equivalence to a standard germination test. The system is designed upon the S-100 bus. System design, hardware, software, and applications are discussed.
Additional index words: seed analyzer, seed testing, microcomputer, laboratory automation, data acquisition, software.
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Dynamic Conductrometric Analysis of Peanut (Arachis hypogaea L.) Seed Leachate Using the CASAS (Computerized Automated Seed Analysis System)
R. D. Keys2
A Dynamic Conductometric Analysis of peanut seed (Arachis hypogaea L.) has been developed. The analysis is programmed into the CASAS (Computerized Automated Seed Analysis System), and requires a three hour time period. A linear model of total ionic leaching from the seed is derived from a sample under analysis, for comparison with a general population model for commercial acceptability based upon a 70% germination equivalence criterion. After initial startup and calibration of the equipment, the analysis is under control of the CASAS.
Additional index words: Seed analyzer, Seed testing, Microcomputer, Software, Seed leachate, Seed electrical conductivity.
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Improving Germination of Skunkbush Sumac and Serviceberry Seed1
P. Weber, L. E. Wiesner and R.. E. Lund2
Skunkbush sumac (Rhus trilobata Nutt.) and serviceberry (Amelanchier alnifolia Nutt.) are native shrubs extensively distributed in the western United States which have achieved importance in revegetation of disturbed lands. Standard germination tests were performed on each species as outlined in the literature. Seed viability was determined with triphenyl tetrazolium chloride (TZ). Results indicated that special techniques would be required to affect the rapid germination needed in current seed testing programs.
Additional index words: Rhus trilobata, Amelanchier alnifolia, gibberellic acid, potassium nitrate, thiourea, benzyladenine, germination, dormancy.
The Effect of Woodchip-Newspaper Mulch on Germination of Grass and Legume Seeds Under Laboratory and Field Conditions1
James E. Brown, Joe B. M addox and Walter E. Splittstoesser2
Seeds of fescue (Festuca arundinacea L.) perennial ryegrass (Lolium perenne L.), sericea lespedeza (Lespedeza cuneata Dum.-Cours.), and red clover (Trifolium pratense L.) were germinated in a slurry of various concentrations of woodchip-newspaper mulch. The germination percentage of all species except fescue was reduced in this media.
Additional index words: boron, clover, fescue, lespedeza, ryegrass.
Density Separation of Seeds With Hexane and Chloroform1
A. G. Taylor2, A. M. McCarthy3, and E. M. Chirco2:
A float-sink technique to separate seeds by density differences is described. Mixtures of hexane and chloroform were used to obtain solutions of 0.66 to 1.47 g/cc, respectively. Wheat (Triticum aestivum L. 'York star') and lettuce (Lactuca sativa L. 'Ithaca') seeds were separated into density fractions of 1.30 to 1.45 g/cc in 0.05 increments and 1.12 to 1.18 g/cc in 0.02 increments, respectively. Seed protein content and density were positively correlated in wheat. No phytotoxicity was observed from the organic solvents. Seeds of five tree species were separated into two density fractions. The cutting test was performed to determine the percent filled seed. The more dense fraction in all species had the greatest percent filled seed.
Additional index words: specific gravity, seed protein.
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Reduced Steeping Time for the Conductivity Vigor Test of (Phaseolus vulgaris L.) Seed
H . M . Brouwer1 and J. C. Mulder2
The results of two experiments on the conductivity test for bean (Phaseolus vulgaris L.) seed quality are reported.
Additional index words: laboratory germination tests, seed quality assessment, leachates, soak germination test.
Identification and Pathogenicity of Fusarium species Isolated from Surface-Disinfested Watermelon Seed
R. McLaughlin and R. D. Martyn1
Watermelon seeds from 32 commercially grown lots and from 5 lots obtained from locally grown fruits harvested from wilted vines in one field (PV lots) were surface-disinfested, dissected and the seed coat halves and cotyledons plated on Komada's selective medium. Forty-four isolates of Fusarium spp. were single-spored and identified as either F. oxysporum, F. solani, or F. moniliforme.
Additional index words: seed pathology, Cucurbitaceae.