Cultivation Of Radiation-Induced Mutant Of Upland Rice IRAT109 & Gene Mapping Of A Rice Lesion Mimic Initiation Mutant

As one of typical upland rice variety,IRAT109 is used widely for physiological research of drought resistance,gene/QTLmapping,genetic improvement of water saving and drought resistance rice.The most direct and available research method for functional gene in rice is to construct a saturated mutant gene library.This study made IRAT109 as the core material;construct a radiation induction mutant library,set up the research system of functional gene in rice.This study consists of two parts.The first part is the cultivation of 260 Radiation-induced mutants of upland rice IRAT109.This part includes background analysis,traits investigation,classification,construction of populations of 260 mutants and so on.Part three is gene mapping of one of the 260 mutant.The mutant that be chosen is susceptible to drought stress and have lesion mimic on leaves and sheath,that is a distinguished trait.The main results were as follows:1.47 SSR makers are selected for the background detection of 260 mutants. Comprehensive analysis the result of SSR makers and agronomic characters,we identify that 51 mutants are not the self-pollinated progenies of radiation-induced mutants.After eliminating 51 lines,we still have 209 mutants which come from original parent IRAT109. Survey the traits of 209 mutant,we classify them into 20 more type according to the phenotype,such as leaf mutant,stem mutant,panicle type mutant,rice glume mutant, drought resistance mutant and so on.Some mutant whose character variation significantly and has genetic stability are used for constructing population,finally we get 142 populations that can be used for analysis mutant gene.34 mutants whose drought resistance ability is at various levels are selected from 209 mutants.Basing on drought-resistance coefficient and comprehensive agronomic characters,the drought resistance levels of 34 mutants are identified initially,the drought resistance of 6 mutants is decreased obviously.They are divided into drought sensitive type.2.The field investigation show that the ratio of normal plant and lesion mimic initiation plant in two F₂ population of lesion mimic mutant is 12.58:1 and 14.60:1,the chi-square test show that they are fit the ratio of 15:1.So the lesion mimic trait might controlled by two recessive genes.We use F₂ population which the filial generation of 9311 and 07TB-157(lmi mutant) as the mapping population.To detect the genomic differences between two parents,1152 SSR makers were selected.The makers which show polymorphism between two parents are used for analyzing all the recessive individual plant.The gene loci controlling lmi were tagged by RM1374 and RM4771 on the chromosome 10.Genetic linkage analysis show that the genetic distance between one of lmi loci and RM1374 is 22.67cM,and the genetic distance between another lmi loci and RM4771 is 18.62cM.Base on the sequence data of Nipponbare,the physical distance between RM1374 and RM4771 is 1.44Mb,RM1374 and RM4771 may be linked with the two genes which control the lesion mimic trait.