A fertile amphiploid between diploid wheat (Triticum tauschii) and crestedwheatgrass (Agropyron cristatum)

Alloploidy, one of the most efficient evolutionary mechanisms in nature, ha s not been extensively exploited in plant breeding programmes. Many genomic combinations remain to be created by plant breeders, to be used directly a s new crops or indirectly to widen the genetic basis of crops. The Triticea e tribe, to which wheat belongs, is among the botanical groups in which thi s strategy has been successfully explored. However, there remain valuable g enomic combinations that have not been obtained at the diploid level. The A gropyron complex (wheat-grasses) has recently been the focus of attention f or interspecific hybridization, but intergeneric hybrids or amphiploids wit h wheat have not been reported at the diploid level. Here we report synthes is of a tetraploid amphiploid between Triticum tauschii and Agropyron crist atum by crossing two tetraploid accessions. Using total genome in situ hybr idization (GISH) staining on metaphase I pollen mother cells, data on allos yndetic and autosyndetic chromosome pairing have been obtained. These data support the view that the A. cristatum tetraploid parent used in the synthe sis of the amphiploid has a segmental alloploidy nature.