|Raymond, F. Douglas|
|Murphy, J. Paul|
Submitted to: American Oat Workers Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/20/2002
Publication Date: 7/30/2002
Citation: Jellen, E.N., Gardunia, B.W., Durrant, J., Raymond, F., Murphy, J., Livingston, D.P., Santos, A.G. 2002. Segregation patterns in oat populations derived from parents heterozygous for translocations 7c-17 and 6c-21.. American Oat Workers Conference Proceedings. Interpretive Summary: Oat has three sets of chromosomes with seven chromosomes in each set. In some instances an entire piece of chromosomes can break off and become re-attached to another chromosome. This is called a translocation. We have discovered that a translocation in Wintok oat is closely correlated with freezing tolerance which suggests that many of the genes responsible for freezing tolerance in oat reside in or near the portion of the translocated piece. This information will help breeders using modern DNA technology to identify individual genes and use this information to develop a more freezing tolerant oat.
Technical Abstract: Mounting evidence points to the importance of chromosomal rearrangements like reciprocal translocations in the evolutionary history of the genus Avena. These translocations may have profound effects on genetic and breeding behavior of oats, particularly when parents of diverse origins are used in crosses. We have been studying segregation patterns for translocations, genes, and abiotic stress tolerance traits in three oat genetic mapping populations whose parents differed for cytologically identifiable terminal intergenomic translocations. Two of these populations, Fulghum x Wintok (FW) and Population 7, are segregating for the 7C-17 translocation. The third population, SMIG, is segregating for an irradiation-induced translocation involving chromosomes 6C and 21. We observed an abnormal 3:1 (translocation: normal) segregation pattern (1:1 was theoretically expected) among approximately 100 F4:6 recombinant inbred lines derived from the cross between Fulghum (A. byzantina, non-translocation) and Wintok (A. sativa, translocation). The translocation is also highly correlated with cold tolerance contributed by the Wintok parent. Population 7, derived from a cross between Red Rustproof (A. byzantina, non-translocation) and PI 258591 (A. sativa nuda, translocation) is segregating 2 (hulless):1 (hulled, normal): 1 (hulled, fatuoid) in the Fs generation; we are just beginning to score the F6 seed for the 7C-17 translocation, but preliminary data indicate no association between fatuoidy and deletions for either of the translocation segments involved in this chromosome rearrangement. The SMIG population is the product of a cross between Sun II (A. saliva, non-translocation) and N770-165-2-1 (A. sativa, translocation). This population is exhibiting skewed segregation away from homozygous normal plants in early generations of single-seed descent. This population is also yielding fertile duplicate-deficient plants that should permit assignment of genetic markers to the translocation segments, which consist of the subtelomeric region of 6C, short arm, and the NOR-satellite of chromosome 21. Other populations we are developing include Green Russian (7C-17 translocation x Landhafer (non-translocation), Rousse (non-translocation) x Ogle (7C-17 translocation) Kanota non-translocation x PI 258582 (non-translocation, Crete), Landhafer x Black President ( C-17 translocation), Red Rustproof x Terra (hulless, 7C-17 translocation), and Grey Winter (7C-17 translocation) x Vicar (hulless, 7C-17 translocation). We are also working on development of genetic mapping software that can identify translocation breakpoints and derive the correct orientation of translocation segments, particularly in the KO linkage group 3.