Study on mutagenesis of immature embryo callus treated with γ rays in wheat

The mutagenic effect of γ radiation on somaclonal variation of immature embryo callus from wheat was investigated. The results showed that 1 ∼ 1.5 krad was an appropriate exposure dose range which led to a plantlet regeneration rate of irradiated of 50%. Two generations (γR0 and γR1) of the plantlet could be harvested within 1 year with greenhouse culture. Plant grew weakly and variation, such as dwarf plant, small ear and sterile plant, appeared in γR0 generation. There was a high frequency which might reach 65% and a wide variation range in γR1 generation, while the frequency of its control (callus not treated with γ rays) was 32% ∼ 38% in R1 generation. The variant characters included plant-height, ear-shape, shell-color, awnedness and grain. It was proved that γR1 is a favourable generation for selection of good individual plant. 80% and more of variant characters tended to be stable in γR2 generation in the next year, and γR2 could be regarded as a better generation for selection of stable lines. High-yield strain '880114' and the mutants with specific characters, such as early ripeness, dwarfness, macrograin and macrospike, were selected from γR2 generation. Analysis of esterase isozyme indicated that the strains and the mutants all possess characteristic bands