Demographic changes and genetic variation of an alfalfa (Medicago sativa L.) population
| dc.contributor.advisor | Smith, Steven E. | en_US |
| dc.contributor.author | Shi, Niu, 1963- | |
| dc.creator | Shi, Niu, 1963- | en_US |
| dc.date.accessioned | 2013-04-03T13:05:52Z | |
| dc.date.available | 2013-04-03T13:05:52Z | |
| dc.date.issued | 1991 | en_US |
| dc.identifier.uri | http://hdl.handle.net/10150/277907 | |
| dc.description.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. | |
| dc.language.iso | en_US | en_US |
| dc.publisher | The University of Arizona. | en_US |
| dc.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. | en_US |
| dc.subject | Agriculture, Agronomy. | en_US |
| dc.subject | Biology, Genetics. | en_US |
| dc.title | Demographic changes and genetic variation of an alfalfa (Medicago sativa L.) population | en_US |
| dc.type | text | en_US |
| dc.type | Thesis-Reproduction (electronic) | en_US |
| thesis.degree.grantor | University of Arizona | en_US |
| thesis.degree.level | masters | en_US |
| dc.identifier.proquest | 1344028 | en_US |
| thesis.degree.discipline | Graduate College | en_US |
| thesis.degree.discipline | Plant Sciences | en_US |
| thesis.degree.name | M.S. | en_US |
| dc.identifier.bibrecord | .b26917506 | en_US |
| refterms.dateFOA | 2018-06-23T18:30:56Z | |
| html.description.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. |
