Mapping Of A Long Sterile Lemma Gene And Verication Of QTLqGW5.2 For Grain Width In Rice

Rice is one of the most important alimentarn crops in the world,also a model in monocotyledon's genetic research.The floral organ is the basis of rice breeding offspring,is important organ in the process of rice growing and reproducing.The development of floral organ directly affects the yield and quality of rice.In this study,a rice long sterile lemma mutant is obtained by mutagenizing japonica landrace nipponbare rice using Ethylmethane sulphonate(EMS)and,is temporarily named Oslg.In order to locate this mutant,BC1F2 population was constructed for genetic analysis and gene mapping after hybridizing selfing and backcrossing with indica landrace 93-11.Genetic analysis shows,the trait of rice long sterile lemma is controlled by a pair of recessive nuclear genes in BC1F2 population of Oslg/93-11.The Oslg loci is initially located between markers C71 and RM3394 using the published SSR markers and self-developed new markers.Then,the Oslg loci is further located by self-developed markers,and the Oslg gene was finally located between markers C74 and RM3394 on the 7th chromosome of rice,The physical distance is about 210kb,which lays the foundation for further cloning Oslg gene and studying the molecular regulation mechanism of plant floral organ.Rice grain type,including grain width,grain thickness,grain length and other traits,is an important factor affecting the yield of rice production,has a close relationship with quality of rice processing,appearance quality,taste and cooking quality,its developmental and genetic mechanism has been the focus of rice breeders researching.The preliminary study of my laboratory selects wide-grain high-sparing landrace of PXG and narrow-grain semi-dwarf indica N643 as parent materials,BC2F4 population is used for fine mapping after crossing,selfing,backcrossing,a major QTL loci of controlling grain width is detected on chromosome 5,qGW5.2,is located between markers RMw513 and RM18060,its contribution rate is 57.3%and LOD is 17.5.In my study,basing on the pre-location result of my laboratory,in order to verifing pre-location result,i select obvious separation families in BC2F5 population of PXG X N643 backcross progeny,Finally,the grain width gene qGW5.2 is located in the range of 140kb between markers L513 and L529,its contribution rate is 34.6%and LOD is 6.6,which is consistent with the interval of pre-location.qGW5.2 contribution rate are more than 30%in two populations,indicating that the expression of qGW5.2 is stable in different populations,and the nearest grain-type gene GW5 has a 500kb distance with qGW5.2,so it is proved that qGW5.2 is a stable and new Genetic gene.