Abstract
Cytoplasm (from Aegilops species carrying the D genome)/chromosome (chromosome 1D or 1DL from alloplasmic lines of Triticum aestivum cv. Chinese Spring) interactions were investigated for their effects upon pollen and selfed seed fertility. The cytoplasms of Ae. squarrosa, Ae. cylindrica and Ae. ventricosa had the greatest effect in reducing pollen fertility (33.0- 41.9%) and selfed seed fertility (18.7-78.7%) upon interaction with monosomic 1D-trisomic 1A, monosomic 1D-trisomic 1B, monosomic 1D, monotelosomic 1DL, and monotelodisomic 1DS. The cytoplasms of Ae. crassa 4x and 6x, Ae. juvenalis and Ae. vavilovii had a lesser effect (45.4-92.8% pollen fertility and 20.0-95.8% selfed seed fertility) in the same interactions. These results lead to the inescapable conclusion that the absence of chromosome 1DL and the cytoplasms of the first three Aegilops species discussed above interact with wheat genomes to reduce microgametophytic viability. The cytoplasms of the second group of Aegilops species interacted with wheat genomes lacking chromosome 1D in a quantitatively different, but significant way. It is postulated that a gene (s) for microgametophytic viability is located on chromosome 1DL, and that the absence of the gene(s) of T. aestivum genomes results in partial breakdown of microgametogenesis in interaction with the cytoplasms of the second group of Aegilops species.
