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dc.contributor.advisorByrne, Patrick
dc.contributor.authorLu, Jie
dc.contributor.committeememberGreene, Stephanie
dc.contributor.committeememberReddy, Anireddy
dc.date.accessioned2017-09-14T16:04:03Z
dc.date.available2018-09-12T16:04:38Z
dc.date.issued2017
dc.description2017 Summer.
dc.descriptionIncludes bibliographical references.
dc.description.abstractConserving genetic diversity is one of the major tasks for seed banks worldwide. At present, there are two long-term preservation methods in the USDA-ARS National Laboratory of Genetic Resources Preservation (NLGRP):storage in a -18 °C vault (conventional storage) and storage in a liquid nitrogen vapor phase ranging from -135 oC to -180 °C (cryopreservation). Cryopreservation is considered to be the best method for long-term storage of vegetatively propagated plants and sometimes can be effective for recalcitrant seeds, but its value for orthodox seeds has not been thoroughly tested. Rye (Secale cereale L.) is a diploid allogamous plant species with 2n=14, a relatively high degree of gametophytic self-incompatibility and orthodox seeds. It has been an important crop in Europe and one of its major uses nowadays is in wheat breeding. In order to test the effects of long-term cryopreservation of orthodox seeds, 40 rye accessions (20 with spring habit and 20 with winter habit) stored for 25 years under both conventional storage and cryogenic conditions were evaluated. In our research, field and seedling evaluation and DNA methylation experiments were conducted. Winter rye seeds were planted in October 2014 and spring rye seeds were planted in April 2015 at CSU's Agricultural Research Education and Development Center (ARDEC) near Fort Collins, CO. Seedling evaluation was conducted at NLGRP in 2014-2015. A methylation sensitive amplified fragment length polymorphism (metAFLP) technique was used to evaluate DNA methylation of two accessions of the 40 total accessions used in the field experiment. This experiment was conducted in the summer of 2016. In the field evaluation, only spike length in the winter trial was significantly different (P=0.045) between storage treatments. Spikes of plants grown from conventionally stored seeds were slightly longer than those from cryopreserved seeds. Seedlings from cryopreserved samples had significantly higher normal germination percentage (P<0.0001) and lower abnormal germination percentage (P<0.01) than those stored under conventional conditions. In addition, root length in the winter trial and average root diameter in both trials showed significant differences (P<0.05) between the two storage treatments. Seedlings from cryopreserved seeds had longer roots and smaller root diameter than seedlings from conventionally stored seeds in the winter trial and seedlings from conventionally stored seeds had smaller root diameter than seedlings from cryopreserved seeds in the spring trial. No other significant differences between storage methods were detected. Our results indicated that cryopreservation has only minimal affects on phenotypic variation and may preserve seed for a longer period than conventional storage in orthodox cereal seeds. In the metAFLP experiment, only 5 of 311 loci in accession V/108 and 3 of 308 loci in accession Omka showed unadjusted methylation status differences between the two storage treatments at the P=0.05 significance level. However, after false discovery rate (FDR) adjustment, no differences in methylation were detected between storage treatments on an individual locus basis. To my knowledge, this study was the first evaluation of long-term cryopreservation versus conventional storage in orthodox seeds. The results indicated that cryopreserved seeds had increased viability; plants grown from cryopreserved seeds has only minimal phenotypic differences; and no epigenetic differences were detected compared to conventionally stored seeds. Therefore, based on the results of this study, cryopreservation is an appropriate method for long-term storage of rye seeds.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.identifierLu_colostate_0053N_14168.pdf
dc.identifier.urihttps://hdl.handle.net/10217/183849
dc.languageEnglish
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019 - CSU Theses and Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.titlePhenotypic changes and DNA methylation status in cryopreserved seeds of rye (Secale cereale L.)
dc.typeText
dcterms.embargo.expires2018-09-12
dcterms.rights.dplaThe copyright and related rights status of this item has not been evaluated (https://rightsstatements.org/vocab/CNE/1.0/). Please refer to the organization that has made the Item available for more information.
thesis.degree.disciplineSoil and Crop Sciences
thesis.degree.grantorColorado State University
thesis.degree.levelMasters
thesis.degree.nameMaster of Science (M.S.)


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