Fast Neutron Irradiation Represses Germination and Survival in Diploid and Hexaploid Wheat

Mutants are valuable genetic resources for fundamental research and applied studies in cereal crops. In wheat, mutants have been created using chemical agents (e.g. ethyl methanesulfonate) and physical irradiations (e.g. gamma ray). Here, we studied the effect of fast neutron (FN) on diploid wheat (Triticum monococcum ‘DV92’) and hexaploid wheat (T. aestivum ‘Brundage’ and ‘01-10704A’). Mature seeds were treated in the McClellan Nuclear Research Center (CA, USA) using the FN doses from 7 to 49 gray (Gy) with an increment of 7 Gy per treatment. Based on germination test, FN irradiation significantly repressed the growth of shoots and roots; FN doses had a negative correlation with the seedling size. Twenty-eight superior seedlings in each treatment were transplanted into soil in greenhouse. For diploid wheat, seedlings from the 7 Gy treatment survived, but they were smaller in size and less in leaf numbers than the ones in wild-type controls. For hexaploid wheat, seedlings from the 7 to 21 Gy range survived, of which the 7 Gy treatment had no significant effect on plant sizes (except 01-10704A) and leaf numbers, the 14 Gy treatment significantly repressed plant sizes but not on leaf numbers, while the 21 Gy treatment significantly repressed plant sizes and leaf numbers. Most seedlings from higher doses (≥ 28 Gy in Brundage and 01-10704A; ≥ 14 Gy in DV92) did not survive. Taken together, fast neutron is effective in introducing mutants in wheat. The current study provides preliminary data for generating wheat mutants using fast neutron.