| An X-ray induced awned mutant in Thatcher wheat1 F.-T. KAO, E. R. AUSEMUS, H. STEVENS and R. S. CALDECOTT Agronomy and Plant Genetics Department University of Minnesota, St. Paul, Minn., U.S.A. A fully awned plant was found in the second cycle of a recurrently X-irradiated population of awnless Thatcher wheat (Triticm vulgare). This mutant differs phenotypically from its progenitor in that it is fully awned (approximately 50-70 mm in length) from the apex to the base of the spike, and the beaks of all outer glumes have an awned extension approximately 15-25 mm in length. Seed from the mutant was increased in Mexico during the winter of 1960-61. Preliminary tests of the agronomic characters of the mutant and parental types were made in rod-row trials at St. Paul, Minn, in 1961 (Table 1). In addition, milling and baking quality tests were conducted by the Department of Agricultural Biochemistry of the University of Minnesota (Table 2). From these data it is clear that, for all the characters examined except awning and mixing time, the lines are indistinguishable. Whether one mutational event determines both these traits is not known; however, in all agronomic characters, except awning, the lines appear to be identical and, therefore, may be isogenic. Because awning in T. vulgare is known to be governed by two allelic series and several suppressor and modifying genes, studies will be set up with a nullisomic series to determine if the induced mutant is at the same locus as a naturally occurring gene for awn development. A small quantity of seeds of the mutant, and the Thatcher selection from which it was derived, are available for distribution to breeders and geneticists. |
| 1 Cooperative investigations, the University of Minnesota Agricultural Experiment Station, Crop Research Division, ARS, USDA, and the University of Idaho. This work was conducted under Contract No. AT(11-1)-332 between the University of Minnesota and the U. S. Atomic Energy Commission. |