Genetic Analysis And Gene Mapping Of Agronomic Traits In Rice Mutants

Rice is one of the most important food crops in the world.By virtue of its relatively small genome,easily to be operated and easily to be transferred,also its chromosome with other cereals crops are characterized by collinearity,so rice is a model plant for functional genomics research.With the post-genome era coming,more and more researchers attach importance to mutant research,not only because it is the fundamental research material, but also the research materials for rice functional genes.In this study,we screened, identified and analyzed of the library of a rice T-DNA inserted mutants,for ZH11 as receptor,and gene mapped the multi-trait mutant P1308.At the same time,carried out genetic analysis and gene mapping on a lax mutant which is come from natural variation. The main results are following:1.The traits of T-DNA mutants,which mutated from ZH11,are investigated and screened.300 stable lines of phenotype variant are obtained.The traits,which mutated, include heading date,plant height,leaf colour,plant type,flower development and so on. Screen some mutants to do a co-segregation analysis.Choose some mutants with important agronomic traits to construction gene mapping groups.We can confirm that 9 mutants are due to T-DNA insertion caused,and agronomic traits changed,the total separation analysis of P1288,P1294,P1297,P1298,P1308,P1410, P1426,Q1281 showed that,they are controlled by a single recessive gene,and premature senescence of the P1444 is controlled by multi- gene which caused by the aging process in advance.In this study,we use PCR walking,TAIL-PCR,reverse PCR and other methods to amplified exploration of T-NDA flanking sequence in yellow green leaf mutant Q1281 and multi-trait mutant P1308.We get the fill sequence of T-NDA and such as non-specific amplification.SSR markers are used to gene mapping the multiple traits of mutant P1308,we found control its positioning mutant gene is on chromosome 12 and existence of linkage with RM17,genetic distance is 5.3cM. 2.In this study,we obtained a rice lax mutant from natural variation.The main characteristics of lax mutant as follows:there is no significant difference between wild-type except spike.The primary and secondary rachis-branches are normally initiated, but most lateral spikelets are absent.Every spikes has low Grain density,so rice production has dropped significantly.To study the genetic law,hybrid lax2(t) with 9311,G46B,261,02428.The normal and lax2(t) were segregated in all the F₂ populations from the 4 crosses and the segregation ratios fit well to 3:1.These results indicated that lax was controlled by a single recessive gene.According to genetic analysis,by using bulked segregation analysis on an F₂ population developed from the cross of lax and 9311,this gene was mapped close to two SSR makers,RM1359 and RM16874,on chromosome 4,with genetic distance of 7.3 cM and 1.8 cM.According to the lax phenotype,genetic analysis and gene mapping situation, the gene was deemed to a novel gene,tentatively named lax2(t).The results of the gene mapping can lay the foundation for further fine mapping and gene cloning.