Production of embryo - callus - regenerated hybrids between Triticum aestivum and Agropyron cristatum possessing one B chromosome

mdash; Plant regeneration from immature intergeneric embryos through direct callus induction was investigated in the case of hybridization between T aestivum cv Chinese Spring (2n = 6x = 42, AABBDD) and A cristatum 4x with one B chromosome (2n = 4x = 28 + 1 B, PPPP). Twenty-three abnormal immature hybrid embryos were directly cultured on MS solid medium with 2 mg / L 2,4-D to induce calli which were then transferred to hormone free MS medium for plant regeneration. All the embryos formed calli. Plantlets were regenerated from 56% of the calli induced from the torpedo-shaped abnormal embryos without scutellum and 82% of calli from small abnormal embryos with scutellum. Forty-three regenerated plantlets were produced from a single hybrid embryo. Most hybrid plants had 2n = 5x = 35