Inflorescence culture of Triticum aestivum × Secale cereale hybrids: production, characterization and cytogenetic analysis of regenerated plants

Abstract

In vitro culture of immature inflorescences of F1 hybrid plants originating from the cross between the common wheat cultivar Roazon and two inbred lines of rye was carried out with 2,4-dichlorophenoxyacetic acid in the medium. After 3 or 8 weeks of culture as undifferentiated callus, 62 plants could be regenerated. Of these, 47 reached the adult stage; 46 of which were analysed for chromosome counts and chromosome pairing. For 44 of these, chromosome counts showed high stability and phenotypes were similar to those of the mother plants. In vitro culture of immature inflorescences could therefore be considered as a possible vegetative multiplication method to obtain numerous copies from one individual. The three other plants exhibited variations in phenotype and chromosome number: one was an amphiploid, and a chromosome was lost in each of the other two. All meristematic cells and pollen mother cells were involved in these numerical changes for each plant. The amphiploid plant (2n = 56) was nonchimeric and all the spikes were highly self-fertile. It could be an efficient method for chromosome doubling. This underscores the usefulness of inflorescence tissue culture for overcoming the sterility barrier in interspecific hybrids.Key words: wheat × rye hybrids, tissue culture, amphiploidization, aneuploidy, meiotic behaviour.