Demographic changes and genetic variation of an alfalfa (Medicago sativa L.) population

Persistent Link:
http://hdl.handle.net/10150/277907
Title:
Demographic changes and genetic variation of an alfalfa (Medicago sativa L.) population
Author:
Shi, Niu, 1963-
Issue Date:
1991
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:
The objectives of this study were to describe demographic change in an alfalfa population and determine whether genetic changes were associated with stand loss in an alfalfa field during the year of establishment. A nondormant composite population (AZ-88NDC) was sown at 1944 seeds per square meter in Oct. 1988 at Tucson, AZ. Only 29% of the seeds sown germinated and emerged. Survivorship curve of the emerged seedling population had some characteristics of Deevey type III. Two heavy mortality periods were observed. Low temperatures might be the major cause of the first heavy stand loss. The second significant stand loss could be explained by increased density stress. Isozyme profiles were produced from 60 day survivors dug from the field, unselected greenhouse-grown AZ-88NDC (='Unsel') and 300-d progenies produced by intermating plants surviving 300 days. Significant differences were observed in overall level of population heterozygosity of 60-d and unselected populations based on fixation indices of six isozyme loci. This suggests that genetic changes may be associated with establishment of an alfalfa stand.
Type:
text; Thesis-Reproduction (electronic)
Keywords:
Agriculture, Agronomy.; Biology, Genetics.
Degree Name:
M.S.
Degree Level:
masters
Degree Program:
Graduate College
Degree Grantor:
University of Arizona
Advisor:
Smith, Steven E.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleDemographic changes and genetic variation of an alfalfa (Medicago sativa L.) populationen_US
dc.creatorShi, Niu, 1963-en_US
dc.contributor.authorShi, Niu, 1963-en_US
dc.date.issued1991en_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.abstractThe objectives of this study were to describe demographic change in an alfalfa population and determine whether genetic changes were associated with stand loss in an alfalfa field during the year of establishment. A nondormant composite population (AZ-88NDC) was sown at 1944 seeds per square meter in Oct. 1988 at Tucson, AZ. Only 29% of the seeds sown germinated and emerged. Survivorship curve of the emerged seedling population had some characteristics of Deevey type III. Two heavy mortality periods were observed. Low temperatures might be the major cause of the first heavy stand loss. The second significant stand loss could be explained by increased density stress. Isozyme profiles were produced from 60 day survivors dug from the field, unselected greenhouse-grown AZ-88NDC (='Unsel') and 300-d progenies produced by intermating plants surviving 300 days. Significant differences were observed in overall level of population heterozygosity of 60-d and unselected populations based on fixation indices of six isozyme loci. This suggests that genetic changes may be associated with establishment of an alfalfa stand.en_US
dc.typetexten_US
dc.typeThesis-Reproduction (electronic)en_US
dc.subjectAgriculture, Agronomy.en_US
dc.subjectBiology, Genetics.en_US
thesis.degree.nameM.S.en_US
thesis.degree.levelmastersen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSmith, Steven E.en_US
dc.identifier.proquest1344028en_US
dc.identifier.bibrecord.b26917506en_US
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