AGRONOMIC AND MOLECULAR EVALUATION OF INDUCED MUTANTS IN RICE (Oraza sativa L.)

Abstract

5 were the most widely grown Japonica and Indica rice varieties in Egypt, during the last period, possessed at that time many positive agronomic characteristics (e.g., wide adaptability, high yield potential, resistance to multiple diseases, and pests and good grain quality. But now, it has some drawbacks in its characters that make it ideal genotypes for identifying mutational changes traits for agronomic importance. Dry seeds of the above mentioned varieties were treated with different doses of gamma rays (100,200,300,400,and 500 Gy), at the National Center for Radiation Research and Technology, Nasr City, Cairo, Egypt, for raising M1 generation. M1 plants were established by transplanting in 2000 season. Seventy seven independent lines have been advanced to M5 generation, enabling evaluation of quantitative traits by replicated trials and promising lines were selected and tested over three seasons as M6, M7 and M8 generations. Morphological variations at vegetative and reproductive stages including plant type, and yield and its component characters are commonly observed in the five populations. The mutant characteristics identified, so far, consist of better resistance to lodging, blast disease, high yield potential, as well as, early maturity. The results obtained from field evaluation over three years, and, also, through PCR detection, indicated that the induced mutants were differed genetically from their parents. Therefore, these mutants could be used as a donor parents in the rice breeding program and some of them could be recommended to be new rice varieties, suitable to be grown in rice belt in Egypt, such as Giza 175-M13 line.