Determination of optimum dosage of the mutagen ethyl methanesulphonate (EMS) for mass treatment of shoot tips of banana variety ‘Agra’

Abstract

Fusarium wilt disease is the main threat to the commercial cultivation of kolikuttu (silk) banana (Musa spp.). Therefore, efforts were made to improve Kolikuttu banana through induced mutation to enable development of tolerant varieties to Fusarium wilt disease. Shoot apices of in-vitro proliferated banana variety ‘Agra’ were treated with a series of ethyl methanesulfonate (EMS; 0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0% v/v) along with two incubation periods (2 h and 3 h) to identify the optimum concentration of the mutagen. The estimated LD50 values, based on the survival percentage, were 2.63% and 1.6% for 2 h and 3 h, respectively. Fresh weight was reduced by 50% of the control at EMS concentrations of 1.58% and 1.27% while LD50 values for shoot height reduction were 1.71% and 1% for 2 h and 3 h immersions, respectively. Linear reduction of number of buds with increasing EMS dosages was much prominent with 2 h incubation and the estimated LD50 values for this parameter were 1.72% and 1.24% for 2 h and 3 h incubation, respectively. At lower dosage levels, the multiplication ratio over four subculture cycles showed considerable variations. Multiplication was completely arrested at dosages >1.5%.