Abstract

Ethylmethanesulphonate (EMS) is the most useful chemical mutagen to induce genetic variation in plant breeding programs. Key factors in inducing mutations with EMS include dose, genotype, temperature and duration of treatment. This study was conducted to determine the optimum EMS concentration, treatment temperature and duration for effective mutagenesis in selected wheat varieties. Seeds of four varieties (B936, B966, SST387 and SST875) were treated with four EMS concentrations (0, 0.3, 0.5 and 0.7%), three temperature regimes (30, 32.5 and 35°C) at four treatment durations (0.5, 1, 1.5 and 2 h) with two replicates. Percentage seedling emergence, germination and seedling height were recorded for the treatment combinations. The most effective treatment in variety B936 was 0.7% EMS at 30°C for 1.5 h exposure. B966 responded best at 0.5% EMS at 35°C for 1.5 h; SST387 at 0.5% EMS, 32.5°C and 2 h and SST875 at 0.5% EMS, 32.5°C and 1 h. Increased EMS dose, temperature and exposure time were detrimental to seeds of the respective varieties. The study established varietal specific EMS dose and treatment conditions to be used in inducing large-scale mutagenesis in wheat.

Key words: Chemical mutagenesis, ethylmethanesulphonate (EMS), Triticum aestivum.