GERMINATION AND CHARACTERIZATION OF GUAYULE (Parthenium argentatum GRAY) SEED

Persistent Link:
http://hdl.handle.net/10150/193591
Title:
GERMINATION AND CHARACTERIZATION OF GUAYULE (Parthenium argentatum GRAY) SEED
Author:
Jorge, Marcal Henrique Amici
Issue Date:
2005
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Guayule (Parthenium argentatum Gray) is a natural rubber producing plant presently being commercialized for production in arid and semi-arid regions of the world. Inconsistent seed (achenes) quality and the lack of methods to discriminate between good and bad seed lots are significant problems, allowing commercial stands to be established only by transplants, rather than by more cost effective direct-seeding. The objective of this study was to investigate why guayule seed and seed lots vary significantly in quality. The laboratory and greenhouse experiments involved separation of seed based on physical attributes (diameter, color and weight) and the confirmation of internal structures (embryo and endosperm) by x-ray analysis. The effect of different conditioning treatments on seed lots was also tested. Separation of seed by size (diameter) was shown to be less efficient than separation by color. Color was the most effective means of separating heavier and darker (opaque-black and gray color grades) seed, and these seed were confirmed to be filled, containing internal structures by x-ray analysis. Germination percentage and rate were greater for seed with these characteristics than for yellow and bright-black seed, which are lighter and predominately partially filled or unfilled. Conditioning treatments used for guayule seed older than two years had no effect on seed germination and emergence percentage or rate. However, differences in germination and emergence were found among lines, therefore, differences among seed lots appear to be due to variation in the number of filled seed. The quality of seed lots was significantly improved when seed were separated based on color first, then by weight. The separation of good quality seed (filled) from poor quality seed (unfilled) is crucial to lower the costs of stand establishment by direct seeding. Therefore, the quality of seed lots can be improved significantly (higher proportion of filled seed) by separating first by color, then by weight.
Type:
text; Electronic Dissertation
Keywords:
Plant Science
Degree Name:
PhD
Degree Level:
doctoral
Degree Program:
Plant Science; Graduate College
Degree Grantor:
University of Arizona
Advisor:
Ray, Dennis T.
Committee Chair:
Ray, Dennis T.

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleGERMINATION AND CHARACTERIZATION OF GUAYULE (Parthenium argentatum GRAY) SEEDen_US
dc.creatorJorge, Marcal Henrique Amicien_US
dc.contributor.authorJorge, Marcal Henrique Amicien_US
dc.date.issued2005en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractGuayule (Parthenium argentatum Gray) is a natural rubber producing plant presently being commercialized for production in arid and semi-arid regions of the world. Inconsistent seed (achenes) quality and the lack of methods to discriminate between good and bad seed lots are significant problems, allowing commercial stands to be established only by transplants, rather than by more cost effective direct-seeding. The objective of this study was to investigate why guayule seed and seed lots vary significantly in quality. The laboratory and greenhouse experiments involved separation of seed based on physical attributes (diameter, color and weight) and the confirmation of internal structures (embryo and endosperm) by x-ray analysis. The effect of different conditioning treatments on seed lots was also tested. Separation of seed by size (diameter) was shown to be less efficient than separation by color. Color was the most effective means of separating heavier and darker (opaque-black and gray color grades) seed, and these seed were confirmed to be filled, containing internal structures by x-ray analysis. Germination percentage and rate were greater for seed with these characteristics than for yellow and bright-black seed, which are lighter and predominately partially filled or unfilled. Conditioning treatments used for guayule seed older than two years had no effect on seed germination and emergence percentage or rate. However, differences in germination and emergence were found among lines, therefore, differences among seed lots appear to be due to variation in the number of filled seed. The quality of seed lots was significantly improved when seed were separated based on color first, then by weight. The separation of good quality seed (filled) from poor quality seed (unfilled) is crucial to lower the costs of stand establishment by direct seeding. Therefore, the quality of seed lots can be improved significantly (higher proportion of filled seed) by separating first by color, then by weight.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectPlant Scienceen_US
thesis.degree.namePhDen_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplinePlant Scienceen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorRay, Dennis T.en_US
dc.contributor.chairRay, Dennis T.en_US
dc.contributor.committeememberOttman, Michaelen_US
dc.contributor.committeememberCoffelt, Terry A.en_US
dc.contributor.committeememberThompson, Thomas L.en_US
dc.identifier.proquest1247en_US
dc.identifier.oclc137354601en_US
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