The genome constitution and phylogeny of hexaploid timothy (Phleum pratense L., 2n = 42) have been studied with C-banding and genome-specific DNA techniques. The cultivated species and two diploid wild relatives P. alpinum (2n = 14) and P. bertolonii (2n = 14) were karyotyped. In P. pratense, two sets of seven chromosomes could not be distinguished from each other either in gross morphology or in C-banding patterns and the third set was found to be differentiated from them. Two genomes, A and B, were established in this species presumably with the genome formula of AAAABB. The banded karyotype in P. alpinum was close to the A genome and that of P. bertolonii was analogous to the B genome, which suggests these wild species were the genome donors of P. pratense. To reinforce this, a molecular assay was performed with genome-specific probes. Eight clones specific to the genome of P. alpinum and thirteen specific to the genome of P. bertolonii were respectively isolated from the genomic DNA libraries of P. alpinum and P. bertolonii. Three P. alpinum-specific sequences and three P. bertolonii-specific sequences were used as probes to hybridize the DNA of P. pratense on slot blot and Southern blot. All the three P. bertolonii-specific probes and two of the three P. alpinum specific probes exhibited cross-hybridization to P. pratense DNA. This has confirmed the allopolyploid origin of hexaploid P. pratense. In addition, phenotypic variations of seed storage proteins were investigated within the cultivated P. pratense with SDS-PAGE analysis. A total of 44 protein monomers were detected in mature seed extracts from 19 cultivars of timothy. The protein banding patterns were differentiated among all the examined cultivars except for two pairs. Such differentiation makes it possible to identify the timothy cultivars.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.70322 |
| Date | January 1991 |
| Creators | Cai, Qinyin. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Plant Science.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001276618, proquestno: AAINN74797, Theses scanned by UMI/ProQuest. |
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