Radiation-induced hyperdiploidy inHyoscyamus niger L

Summary A hyperdiploid plant type, approaching the triploid chromosome number, and representing possibly a high level of tetrasomy, was recorded in the progeny of a gamma ray-induced unbranched desynaptic mutant in the M₄ generation. Its meiotic behavior and its possible importance for deriving diverse hyperdiploid lines from desynaptic mutants are outlined.Acknowledgment. We are grateful to Dr Akhtar Hussian, Director, CIMAP, for his keen interest in the study and for providing the facilities.