The dwarf genotypes used in our studies represent three distinct sources of dominant dwarfing genes (Dw6, Dw7, and Dw8).
V included Kanota and the Dw8 backcross derivatives AV12/9/9, AV16/8/4, AV14/5/1, AV17/ 3/10, and AV18/2/4.
The Dw8 gene, shown by allelism tests to be present in a series of Japanese lines generated from dwarf A.
When the other Dw8 lines were tested in a similar experiment, each of them also responded to both G[A.sub.1] and G[A.sub.20] (Exp.
Dwarf lines carrying the Dw7 or Dw8 genes also responded much like their nondwarf counterparts to applied GA (Table 4).
Independence of Dw6, Dw7, and Dw8 from the mapped phytochrome loci indicates that they are not alleles of these phytochrome genes.
The dominant oat dwarfing genes Dw6, Dw7, and Dw8 appear to be quite distinct from the wheat Rht1 and maize Dw8 dominant dwarfing genes because of their difference in GA-sensitivity; however, these oat genes may be similar to GA-sensitive dominant genes which have been identified in wheat and rye.
The Dw8 gene significantly shortened all internodes but did not affect internode number.
The frequency with which Dw8 produced a recognizable effect in oat lines with different genetic backgrounds was as expected for a single dominant gene.
[F.sub.2] progeny segregation from crosses of Dw8 dwarf lines with oat elite lines grown in a field nursery in 1992.