Induction and differentiation of haploid Triticum aestivum cv. Chinese Spring callus initiated from haploid embryos

Abstract

Haploid embryos were produced by Triticum aestivum×Hordeum bulbosum crosses. Approximately 4300 florets of T. aestivum cv. Chinese Spring were emasculated and pollinated with pollen of diploid and tetraploid H. bulbosum. Haploid seeds started aborting 8-10 days after pollination and at this stage embryos were excised. Total haploid embryo set was only 0.2%. Callus was induced from the haploid embryos and root apices excised from the haploid plants on T medium+1 mg/L 2,4,5-trichlorophenoxyacetic acid. These calli were subcultured once and then put on differentiation media: T medium and T medium with indole-3-acetic acid (IAA), naphthaleneacetic acid (NAA), IAA+6-furfurylaminopurine (kinetin, K), or NAA+K. Histologically, calli growing on auxin medium were heterogeneous with peripheral meristematic loci embedded in a parenchymatous mass of cells. On differentiation media calli produced copious roots from the meristematic loci. One callus on control medium (T only) gave rise to an isolated shoot. The chromosome number of differentiated roots was always 2n=3=21.