Gene Mapping Of Mutant Of Narrow Leaf In Rice

Since the 1990 s,rice yield has been hovering,so it is urgent to innovate the rice germplasm.Leaf morphology is an important part of ideal plant-type of rice,including the width,thickness,growth angle,and crimpness,etc.it is important to study the narrow leaf mutant,which will provide the basis for leaf developmental regulation and plant-type breeding of rice.Currently,ten genes relative to narrow leaf mutant named nal1 to nal10 had been mapped,they were located on chromosomes 1,3,4,7,11 and 12,respectively.Luhui17 was induced by ethyl methyl sulfonate（EMS）at College of Agricultural,Guizhou University in 2010,and obtained a stable genetic narrow leaf mutant after several generations of selection and identification.The narrow leaf mutant was named narrow leaf 11（nal11）.Nal11 were reciprocally crossed respectively with Mianhui 727,R30 and Fuhui 838 to construct F1 and F₂ populations for genetic analysis and gene mapping of nal11.The main results were as follows: 1.Phenotype analysis of nal11The narrow leaf traits of the nal11 were not apparent at seedling stage,until the rice tillering after it appeared gradually.Width of the flag leaf and the 2nd and 3rd leaves from the top of this mutant was significantly narrower than that of Luhui17,however,there was no difference in length of functional leaves between them,and chlorophyll SPAD value of nal11 decreased significantly at heading stag.Plant height of nal1 was slightly shorter than that of Luhui17 and tiller number of nal11 significantly increased at the mature stage.In terms of yield traits,Kernel number of nal11 was less,the seed setting rate of nal11 was lower,1000-seed weight of nal11 was lighter and grain width of nal11 were shorter than that of Luhui17,however,there was no difference in grain length between them.2.Genetic analysis of nal11nal11 were reciprocally crossed with Mianhui 727,R30 and Fuhui 838 respectively to construct F1 and F₂ populations,Leaf width of all hybridization combination F1 was consistent with normal parent,but trait segregation of leaf width occurred in all hybridization combination F₂ populations,and emerged only two phenotypes of normal leaf width and narrow leaves,the ratio of normal and narrow leaf plants accorded with 3:1,which suggested that nal11 was controlled by single recessive nuclear gene.3.Preliminary positioning of nal11Using F₂ groups constructed with the parents of nal11 and Mianhui 727 screened evenly distributed 318 SSR markers on 12 chromosomes of rice,the gene pool and narrow leaved single plant of F₂ groups were screened with SSR markers.Consequently,nal11 gene was primary located in a range of between RM7290 and RM16720 on the chromosome 4 of rice.The genetic distances between nal11 and two SSR markers were separately 36.7 cM and 21.7 c M.4.Fine positioning of nal11In order to shorten the scope of positioning,Three SSR markers including RM5687,RM7290 and RM16720 were found with nal11 gene chain between RM7290 and RM16720.Finally,nal11 gene was located in a range of about 322 kb between RM7290 and RM16720 on the chromosome 4 of rice.The genetic distances between nal11 and two SSR markers were separately 0.8 cM and 0.8 cM.5.The predicted genes of nal11There are 5 genes（i.e.,Os04g26834.1,Os04g26850.2,Os04g26870.1,Os04g26880.1 and Os04g26841.1）annotated in the region of the mutant locus.