M. OKAMOTO
Curtis Hall Univ. of Missouri, Columbia, Mo., U.S.A.
In the F1 between mono-5B (mono-V) of Chinese Spring and Secale cereale (Kyoto Univ. strain No. 230 7II+B chr.), the following plants given in the table were obtained.
Spikes from plants without chromosome 5B were characterized by the presence of erect awns about 1-2 cm long, while those from plants with 5B had short, hooked awns about 5 mm long. Similar differences of awnedness were observed in the 34- and 35- chromosome plants in the F1 of mono-5B x T. timopheevi.
These facts suggest that a gene (or genes) for suppression of awn development is located on chromosome 5B of Chinese Spring. This gene is not effective in Chinese Spring itself nor in hybrids with 4x T. boeoticum. (* This work was supported in part by a grant from the National Science Foundation to Dr. E. R. Sears.)