Abstract:

To compare the effects of different mutagenesis methods on trait variation in Setaria italica mutant library, seeds of the Zhesu 3 variety were treated with either EMS solution or irradiation to construct mutant libraries. The differences between the two mutant libraries were compared, and the genetic stability of mutant progenies was analyzed. The results showed that 212 and 503 mutants were obtained in the M₂ generation by EMS and irradiation mutagenesis, with mutation frequencies of 4.41% and 10.02%, respectively. The EMS-induced mutant population exhibited rich variation in ear types, with 13 different types identified, while the irradiation-induced population showed relatively diverse variations in leaf color and leaf shape. Phenotypes such as tall stalk, dwarf, semi-dwarf, wide leaf, semi-curled leaf, narrow leaf, wrinkled leaf, and short leaf (leaf uprightness) could be stably inherited. In contrast, some traits related to leaf color, leaf shape, and plant type might result from physical damage during mutagenesis and could not be stably inherited. Additionally, some ear mutant traits showed segregation or combined to generate new mutant types in subsequent generations. Therefore, establishing a stable mutant library requires continuous multi-generational selection of mutants obtained through mutagenesis, at least until the M₃ generation or beyond.

Key words: Setaria italica, mutagenesis, mutant, genetic stability, breeding