BIOSYSTEMATIC RESEARCH IN AEGILOPS AND TRITICUM

As Kihara had only 1 to 3 accessions of each diploid analyzer species in his germplasm collection, we conclude the genome formulae for Aegilops and Triticum published by him between 1920 and 1960 were largely based on the typological concept applied to cytogenetic research. The same restriction applies to his concept of "modified genomes" in the tetraploid Aegilops species, which therefore may not actually be modified. Genome analysis by itself is not a very fine-tuned experimental technique. A biological species concept based on several different biosystematic studies in Aegilops and Triticum is preferable to a species concept based only on genome analysis in meiocytes of F1 hybrids. Biosystematic studies recognize Aegilops sharonensis, Ae. peregrina, and Triticum urartu as valid species distinct from other species. Our attempts to resynthesize tetraploid wheats using Ae. speltoides and Ae. searsii as female parents and T. monococcum and T. urartu as male parents met with little success. There may be an embryo lethality mechanism operating in these F1 hybrid combinations. Sterile hybrid plants were obtained with Ae. longissima, Ae. sharonensis, and Ae. bicornis as female parents in crosses with the two Triticum species as males. Amphidiploid seed was obtained with the use of colchicine.