Gametocidal genes in wheat and its relatives. II. Suppressor of the chromosome 3C gametocidal gene of Aegilops triuncialis

Abstract

Chromosome 3C of A. triuncialis, in the monosomic state, causes semisterility in common wheat cultivars (Triticum aestivum). The Japanese cultivar ''Norin 26'' carries a gene that acts as dominant suppressor of the gametocidal gene on chromosome 3C. However, this suppressor gene does not alter the functions of the gametocidal gene on chromosome 4S1 of A. longissima or A. sharonensis. By means of monosomic analyses, the suppressor has been located on chromosome 3B and is designated IgcI. This gene is distributed widely among wheat cultivars bred in central and southwest Japan. In the presence of IgcI chromosome 3C shows no preferential transmission, but is transmitted to offspring at a frequency similar to those of other alien chromosomes. The progeny of plants that carry a single chromosome 3C exhibit chromosome aberrations, and possibly mutations, at high frequencies. Thus, the gametocidal gene on chromosome 3C causes a syndrome similar to hybrid dysgenesis in common wheat.