EFFECT OF MUTAGENIC TREATMENTS ON SOMACLONAL VARIATION IN WHEAT (TRITICUM-AESTIVUM L)

Different wheat genotypes were treated with gamma‐rays, sodium azide (SA) and EMS before tissue culture and immature embryos from M1 plants or plants shortly after exposure to gamma‐rays were used to initiate callus culture. Thousands of plants were regenerated and used to investigate the effect of mutagenic treatments on the regenerated plants and somaclonal variation in the M3R2 and M2R2 generations. The results showed that mutagen‐induced damage in terms of reduction in plant height, fertility and spike length were not outstanding in the regenerated plants as compared with the untreated control. In the M3R2 generation, only SA treatment had significantly higher frequencies of somaclonal variations than the control. Increases in the variation frequencies were observed when explant embryos were irradiated with 2.5 and 5 gy gamma‐rays and the highest frequency appeared when embryos were exposed to 5 gy gamma‐rays on the 5th day after anthesis. Increased variation spectra also resulted from mutagenic treatments and most of the variants recovered were unsuitable for plant improvement. Copyright © 1990, Wiley Blackwell. All rights reserved