Applied mutagenesis in tomato for the isolation of mutants of enhanced fruit quality

Abstract

Spontaneous or induced mutants, with desirable changes in particular characters have been a key material for gene discovery, mapping, functional genomics and breeding in many crops including tomato. The present investigation was undertaken to study the frequency and spectrum of macro-mutations of gamma rays, EMS and their combinations in “Patharkutchi,” the highly adaptable and popular cultivar of West Bengal. The dry seeds were irradiated with 50, 100, 150, 200 and 250 Gy gamma rays. Pre-soaked seeds of this genotype (6 h, in water) were treated with 0.05, 0.10, 0.15, 0.20 and 0.25% ethyl methane sulphonate (EMS) for 8 h at 25 ± 2 oC. Gamma irradiated seeds of this genotype were also pre-soaked (6 h, in water) before treating with 0.15 % EMS solution for 8 h at 25 ± 2 oC as combination treatment. Combination of gamma radiation and EMS caused more damage followed by EMS treatment and gamma radiation, alone in M1 generation. Gamma irradiation (50-150 Gy) was most efficient followed by 0.05- 0.10 % EMS and their combination treatment in inducing wide array of macro-mutation in tomato. One mutant “Dark green fruit” could be isolated from the M2 population of Patharkutchi treated by 150 Gy gamma radiation. This “Dark green fruit” mutant with higher average lycopene (7.49 mg/100 g fresh) and ascorbic acid (35.86 mg/100 g fresh) contents in the ripe fruits emerged as a promising genetic resource for further utilization in breeding tomato for enhancement of lycopene and ascorbic acid content in the fruits.