New Genetic Tools for Improving Oat Winter Hardiness
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Date
2007-12-18
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Abstract
Winter hardiness is a complex trait, and poor winter hardiness limits commercial production of winter oat. The identification of new genetic tools to improve oat winter hardiness will allow for continued increases in oat winter hardiness. The objectives of this research were: identify quantitative trait loci (QTL) for crown freeze tolerance in the 'Kanota' x 'Ogle' mapping population, evaluate the winter hardiness component traits winter field survival, crown freeze tolerance, heading date, plant height, and vernalization responses in a population derived from a cross of winter tender 'Fulghum' with winter hardy 'Norline', examine the relationships between winter hardiness component traits and a reciprocal intergenomic translocation between chromosomes 7C and 17 in the Fulghum x Norline population, develop a genetic linkage map in the Fulghum x Norline population using SSR markers and selected RFLP markers, and identify QTL for winter hardiness component traits in the Fulghum x Norline population.
In the Kanota x Ogle population seven QTL and four complimentary epistatic interactions were identified that accounted for 56% of the phenotypic variation. Ogle contributed alleles for increase crown freeze tolerance at three loci, while Kanota contributed alleles for increase crown freeze tolerance at four loci. All loci where Kanota alleles increased crown freeze tolerance showed complementary epistasis for decreased crown freeze tolerance with the QTL near UMN13. Two of the major QTL identified were in the linkage groups associated with the 7C-17 translocation.
In the Fulghum x Norline population, 7C-17 translocation did not segregate in the expected 1:1 ratio, and twice as many translocation types as non-translocation types were observed. The translocation was significantly correlated with crown freeze tolerance (r=0.72) and winter field survival (r=0.62). The heritability of crown freeze tolerance was 83% and the heritability of winter field survival was 76%. Field heading date was significantly correlated with translocation status (r=0.20). Plant height, vernalization response, and photoperiod response were not associated with the translocation. QTL were identified for winter field survival, crown freeze tolerance, vernalization response, plant height and heading date, and epistatic interactions were identified for all of these traits except plant height. Major QTL for winter field survival (R2=35%) and crown freeze tolerance (R2 =52%) were identified on linkage group FN3 which was associated with the 7C-7 translocation.
In this research, QTL for freeze tolerance in known linkage groups were identified for the first time in oat and specific QTL for winter hardiness component traits were identified in winter oat for first time. The importance of the 7C-17 translocation to oat winter hardiness traits was confirmed. Comparison with previous results explained differential performance between the hardy winter oat cultivars Norline and Wintok. These results suggested how the 7C-17 translocation conferred increased biological fitness in most Avena germplasm.
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Frost Tolerance, Oat, Epistasis, QTL
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Degree
PhD
Discipline
Crop Science
