High-frequency generation and characterization of intergeneric hybrids and haploids from new wheat-barley crosses.

KEY MESSAGE: Hybrid plants and a high frequency of maternal haploids were obtained using an efficient wheat-barley hybridization system (with new genotype combinations) and confirmed by several cytological and molecular tools. An efficient hybridization system between wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) is presented on the basis of three new genotype combinations. A particularly high, 14% frequency of plant regeneration per florets was achieved in the wheat-barley genotype combination of 'Sichuan' × 'Morex'. The genome composition in 42 of the 95 plants regenerated by embryo rescue was determined using ploidy analysis, genomic in situ hybridization and the application of chromosome arm-specific molecular markers (SSR and STS). A high overall frequency (76%) of maternal (wheat) haploids was observed in all the tests for all three cross combinations. A major implication of this observation is that this new hybridization system represents a useful tool to study the mechanism of uniparental chromosome elimination in cereals.