Master of Science / Department of Plant Pathology / Bernd Friebe / Bikram S. Gill / Common, bread, or hexaploid wheat, Triticum aestivum L. (2n=6x=42, AABBDD), has
several relatives in the Triticum/Aegilops complex of the Poaceae family in the Triticeae tribe,
which are valuable sources for broadening genetic diversity and may provide genes for disease
and pest resistance and general wheat improvement. Other wild relatives of wheat also may be
exploited for wheat improvement, such as Haynaldia villosa (L.) Schur. (2n=2x=14, VV). It is a
diploid species with resistance to powdery mildew, wheat curl mite colonization, cereal eyespot
disease, rust diseases, and wheat spindle streak mosaic virus. H. villosa may harbor many other
as yet unidentified traits for wheat improvement. The polyploid nature of bread wheat allows
tolerance to genomic changes, because homoeologous chromosomes from other genomes
compensate for missing wheat chromosomes. In this experiment, we crossed the disomic alien
addition line DA4V (2n=6x=44) with a pair of H. villosa chromosomes added to the wheat
chromosome complement with wheat monosomic for chromosome 4D (2n=41) to produce
4D/4V double monosomic plants. According to centric breakage-fusion mechanisms, univalents
tend to break at their centromeres at meiotic metaphase I producing telocentric chromosomes
with unstable or “sticky” ends that can fuse with the sticky ends of other newly formed
telocentric chromosomes. This fusion results in Robertsonian whole-arm translocations that may
be compensating if a short arm of one chromosome fuses with a long arm of another. Double
monosomic plants were screened cytogenetically and further visualized by genomic in situ
hybridization (GISH). Five transfers were identified, including T4DS.4VL and T4VS.4DL
translocations, and a T4VS-W.W transfer of unknown wheat origin. These results were
confirmed by GISH. The T4DS.4VL and T4VS.4DL translocations are genetically compensating
and should be exploited in wheat improvement.
| Identifer | oai:union.ndltd.org:KSU/oai:krex.k-state.edu:2097/1085 |
| Date | January 1900 |
| Creators | Wilson, Jamie Jo |
| Publisher | Kansas State University |
| Source Sets | K-State Research Exchange |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
Page generated in 0.0018 seconds