Effects of EthyI Methane Sulfonate (EMS) on Mutation of Upland Rice (Oryza sativa L.)

Abstract

Mutation is a tool that has been used occasionally in genetics to enhance the genetic variability and to add something new and diverse to a natural population. This research aims to induce variability in two high yielding upland rice genotypes of Thailand, Dawk Pa-yawm (white rice) and Dawk Kha 50 (brown rice). Seeds of these genotypes were treated with various concentrations of EMS 0.5%, 0.75%, 1% and 1.25% respectively. With the increase in the applied concentrations, there was a continuous decrease in shoot and root lengths. Regarding to regression analysis LD50 of EMS for Dawk Pa-yawm was 1.34% and 1.23% for Dawk Kha 50. Several traits showed a clear fall off when compared to the control population in Mi like plant height, panicle length, number of filled grains and number of grains per panicle, 1000 grain weight and yield per plant while the panicle length was higher in both of the mutants when compared to their control counterparts. Likewise in M2, Dawk Pa-yawm mutant performed better only in plant height as compared to the control population while in rest of the traits mutants of Dawk Pa-yawm were lagging behind the control population. The overall performance of the Dawk Kha 50 mutants were better than the control population in majority of the studied traits like plant height, number of tillers, panicle length, number of panicles, number of filled grains, number of grains per panicle and yield per plant while in 1000 grain weight the control population of Dawk Kha 50 was leading the mutants. SSR analysis using 11 primers was also done to investigate the genetic variation caused by EMS. Two primers, RM 316 and RM 8225 showed the positive variability among mutant and the parent genotypes. Furthermore, there were several mutants in this research which showed some striking new phenotype as well. Hence later selection in the advance generation might be useful to isolate agronomically useful mutants for future use.