Inheritance of a New Dwarfing Gene in Oat
- S. C. K. Milach,
- H. W. Rines ,
- R. L. Phillips,
- D. D. Stuthman and
- T. Morikawa
- U niv. Federal do Rio Grande do Sul, Faculdade de Agronomia, Dep. de Plantas de Lavoura, Av. Bento Goncalves, 7712, Cx.P. 776, Porto Alegre, RS 90012-970, Brazil
U SDA-ARS Plant Science Res. Unit and Dep. of Agronomy and Plant Genetics, Univ. of Minnesota, 411 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108
L ab. of Genetics and Plant Breeding, College of Agriculture, Osaka Prefecture Univ, Sakai, Osaka, 593, Japan
One important goal in oat (Avena sativa L.) breeding is the development of shorter cultivars with increased resistance to lodging. Although seven dwarfing genes have been identified in oat, only two genes, Dw6 and Dw7, are still readily available in breeding programs. New sources of dwarfing genes were recently identified in Japan from accessions of A. fatua L. and introgressed into the cultivar ‘Kanota’. The objectives of this study were to examine seven of these new sources with apparent dominant genes for dwarfness in oat and to determine their usefulness in oat breeding. Allelism tests using analysis of F2 populations demonstrated that a new dominant dwarfing gene is present in the Japanese lines and that it is independent of the Dw6 and Dw7 loci. The symbol Dw8 has been assigned to the dwarfing gene found in the Japanese lines. F2 populations derived from 17 crosses made among the seven Japanese lines did not segregate for height, indicating that the same dwarfing gene or closely linked genes were present in these lines. Based on the numbers of progenies analyzed from these crosses, we concluded that if there are distinct linked dominant dwarfing genes among the Japanese lines, there would be no more than 20% recombination among them. F2 progenies from four Dw8 lines crossed with tall elite lines all segregated in a 3 dwarf: 1 tall ratio. The Dw8 gene, combined with other height modifier genes, may provide new opportunities for breeding for reduced plant height and improved lodging resistance in oat.
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