The Screening Of Mutants And Construction Of Rice Mutant Population For Variety "9311" Of Rice (Oryza Sativa L.)

Rice (Oryza sativa L.) has become a model plant for the study of the cereal genomes in the last decade. Recent completion of the draft sequence for the rice genome has resulted in an explosion of information on rice genes. The challenge for the post-sequencing era is to identify the biological functions for these genes. Of all the approaches used for discovering the gene function, the more useful one is based on a saturated mutagenesis population, which is a straight and efficient way to understand the role of all the genes. In all the methods for constructing the mutant liberary, the physical and chemical mutangenesis might be the main methods, which were simple and effective. They can be used to produce a large number of mutants with high mutagenesis frequence in a short period and to establish a mutant population. The purpose of the present experiment is to screen different plant morphogenesis mutants and rice quality mutants by treating the seeds of the indica rice variety 9311 with y-rays or EMS (Ethyl Methan Sulfonate), of which has been completely sequenced in the whole genome. The mutant library created will be helpful for gene identity and gene functional analysis.For plant traits, some mutants with the variations of leaf, stalk, panicle or root traits were found in the progenies. The total mutants frequence were 5.94% and 3.78%for y-rays and EMS, respectively. Four hundred and seventeen out of the 606 mutants were found in y-rays mutagenesis population, and 189 ones in EMS mutagenesis population. Comparing with EMS mutagenesis, more mutants were screened in y-rays mutagenesis population. Most of the mutants by EMS could be found in y-rays mutangenesis population, but some mutants, such as the purple leaf sheath mutant and lesion resembling disease mutant, were only found in EMS mutagenesis population.The root trait mutants were screened in the two mutangenesis population and some mutants with the variations of short roots, no lateral root, long seminal root or gravity insensitive of root were found in progenies. The root traits mutants frequence were 0.68 % and 0.42% for y-rays and EMS, respectively, and it was lower than the mutagensis frequence for plant traits. Forty-eight out of the 69 mutants were induced by y-rays and 21 ones were induced by EMS. The frequence of short root mutants was higher than that for other root mutants. The mutants without lateral root mutants or short lateral roots mutants had the short seminal root and crown roots simultanously. There was no short lateral root or lateral root for some of the short roots mutants.For the rice quality mutants, 60 mutants were found in y-rays mutagenesis population and the mutant frequence was 0.85%. Among them, there were 1 brown rice color mutant, 14 rice chalkiness mutants, 3 rice shape mutants, 6 rice alkali spreading value mutants, 7 protein content mutants, 14 amylose content mutants, 1 threonine content mutants, 6 lysine content mutant and 8 phenylalanine mutant. The mutant library created for indica rice variety 9311, which include different plant morphogenesis mutants and rice quality mutants, will be helpful for the research in rice founctional genomics and the relationship among the cereal genome.