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United States Department of Agriculture

Agricultural Research Service


item Jellen, Eric
item Rines, Howard
item Fox, Stephen
item Davis, Douglas
item Phillips, Ronald
item Gill, Bikram

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Knowledge of the physical organization of the genetic material of a species is vital to modern efforts to genetically manipulate and modify crop plants to make them more nutritious and productive. In the cereal oat, where this genetic knowledge has lagged behind that in the more common cereals wheat and corn, we have recently succeeded in bringing together several technical ladvances to produce and characterize a set of genetic lines that are key t developing an understanding of how the individual pieces of genetic information or genes are arranged along the oat chromosomes. Chromosomes are the physical structures in each cell of each organism that carry the genes. Each species of organism has its own characteristic number of chromosomes; oat has 21 pairs of chromosomes. The genetic lines we have developed are each missing one chromosome of the 21 pairs. Special staining techniques for identifying the individual chromosomes in cells in a microscope preparation enabled us to identify each chromosome and tell which one is missing in each of our special oat lines. By associating which genes or pieces of DNA are not present in lines missing different chromosomes, we can tell which genes are located on which chromosomes. This knowledge assists the efforts of geneticists and breeders to introduce new genes or find favorable combinations of genes for improved disease resistance, productivity, and improved grain composition in oat.

Technical Abstract: Monosomics are a powerful tool for genetic mapping in allopolyploid plant species such as oat (Avena sativa L., 2n=6x=42). A C-banded karyotype of the oat cultivar Sun II was compared with previously described oat karyotypes and was used to identify the missing chromosome in each line of Sun II aneuploids. These included new aneuploids isolated among derivatives of oat haploids obtained from Sun II oat x maize crosses along with the original Sun II aneuploid set which had been obtained by cytological screening of a Sun II population for spontaneous aneuploids. Eight new Sun II monosomics were identified among the derivatives of haploids from the oat x maize crosses, to make a total of 18 unique Sun II monosomic/nullisomic lines. All seven C-genome chromosomes are represented by Sun II monosomics. Chromosomes 13, 14, and 17 are not represented by Sun II aneuploids but are found in the Kanota monosomic series. Therefore, ,monosomics of some form are now available for all 21 oat chromosomes. A reciprocal translocation involving chromosomes 3C and 14 found in a portion of the original set of Sun II monosomic lines was also described. No new translocations were detected in the Sun II x maize crosses.

Last Modified: 10/18/2017
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