Mutant gigas, KM72 (gig), was originally found in barley cultivar Tochigi Golden Melon after radiation treatment (Tsuchiya, unpublished). This mutant also was found to be allelic to sf, female sterile (Harvey et al., 1968). The detailed morphology of this mutant has been described by Shim et al. (1983, 1984). Previous trisomic analyses have shown that this gene is not associated with chromosome 3, 4, 5, 6, and 7 (Tsuchiya and Haines, 1975; Shin et al., 1984). Chromosome 2 has been tested, but the F₂ population was small. Chromosome 1 has not been tested yet.

Telotrisomic 1L and 1S plants were used as the materials, and crosses were made between Triplo 1L and 1S and plants homozygous for the gigas mutant. Since seed set was poor and growing conditions were a problem, the data from the cross between Triplo 1L × gigas was not obtained. Table 1 lists the result of F₂ segregation from the cross Triplo 1S × gigas. In trisomic portion, 12 of 26 trisomic plants were homozygous recessive; in disomic portion and total population, the wild type vs gig mutant were close to 3:1. The data indicated that this gene is not located on the short arm of chromosome 1. The only possible location of this gene would be on either chromosome 2 or long arm of chromosome 1.

Acknowledgements:

The author wishes to thank Dr. T. Tsuchiya for providing support, advice, and materials to conduct this study.

References:

Harvey, B. L., E. Reinbergs, and B. H. Somaroo. 1968. Can. J. Plant Sci. 48:417-418.

Shim, J., E. Furst, and T. Tsuchiya. 1983. BGN 13:49.

Shim, J. W., A. Shahla, and T. Tsuchiya. 1984. BGN 14:42-43.

Tsuchiya, T., and R. L. Haines. 1975. BGN 5:67-69.