Dwarf-twisted: An induced mutation in Triticum durum Desf

Summary A mutant phenotype, mainly characterized by undulated leaf surface, dwarfism and sterility, has been repeatedly induced by physical (X-rays; thermal and fast neutrons) and chemical (diethylsulphate and ethylmethanesulphonate) mutagenic agents in different varieties of durum wheat. This phenotype is easily detectable at the seedling stage. Neutron treatments are the most effective method to induce this phenotype and a maximum of 0.6% mutations per M₁ spike-progeny was induced after the highest dose of thermal neutrons. On the average 0.23 mutations per 100 M₁ spike progenies and 0.55 mutant seedlings per 1000 M₂ plants were found after all treatments.Genetic analysis of different dwarf-twisted phenotypes shows that this character is conditioned by one recessive gene with an average segregation ratio of 22.9%. As the dwarf-twisted phenotypes segregate in highly fertile M₁ spikes and no evident chromosome changes have been detected in this caryotype, the hypothesis of a point mutation has been proposed.Contribution no. 171 from the Laboratorio Applicazioni in Agricoltura del C.N.E.N., C.S.N. Casaccia, S. Maria di Galeria, Roma, Italy.