Genome Wide Association And Linkage Analysis Of Neck-panicle Vascular Bundles Related Traits In Rice

Rice is not only one of the most important food crops,but also a key model organism for basic and applied research in plant biology.The vascular bundle is conducting tissue in plants.Neck-panicle vascular bundle is closely related to grain-filling,lodging and heat resistance,which decide directly or indirectly rice yield.Therefore,genetic analysis of rice panicle vascular bundle and relevant characteristics is extremely significant for enhancing the gramineous crop production.At present,there are few reports about rice panicle vascular bundle and related QTL.The purpose of this study is to carry out the genome-wide association analysis of rice neck-panicle vascular bundle and related characteristics using the natural population consisted of 524 rice varieties collected worldwide in our laboratory.In order to verify the results of genome-wide association study,F2 population constructed with L76/W82 from the collected natural population was used to conduct the QTL localization analysis of neck-panicle vascular bundle and related characteristics in rice by using CIM with a genetic linkage map established with 139 SSR markers.The main results were as follows:1.The neck-panicle vascular bundle and related characteristics in rice(diameter of neck-panicle,DONP;number of big vascular bundle,NOBVB;area of stem wall,AOSW;whole area of big vascular bundle,WAOBVB;ratio of big vascular bundle area to stem wall area,ROBVBATSWA;ratio of big vascular bundle numbers to small vascular bundle numbers,ROBVBNTSVBN;number of small vascular bundle,NOSVB;area of single big vascular bundle,AOSBVB;area of phloem,AOP;thickness of stem wall,TDOSW;ratio of phloem area to single big vascular bundle area,ROPATSBVBA)were observed by free-hand sectioning.By correlation analysis of these characteristics,many traits showed to be obvious or highly obvious correlation.2.The above 11 traits were analyzed through the GWAS platform established in the collected natural population consisted of 524 rice varieties with the second-generation sequencing technology.Many sites with significant value were detected.3.We analyzed the genotype of 102 lines in F2 population using the selected 139 SSR markers evenly distributed in whole genome from the 190 polymorphic markers between L76 and W82 through screening our laboratory’s 900 SSR markers.A and genetic linkage map was constructed.4.The neck-panicle vascular bundles and related characteristics of 102 lines in F2 population were observed and used for linkage mapping.A total of 18 QTLs with LOD>2.5 were detected.These loci distributed on 10 chromosomes except the fourth and ninth chromosomes.