Genetic Variation Analysis And Key Genes Discovery Related To 1000-Grain Weight Between Paddy Rice And Upland Rice Based On Upland Adaptation

Upland rice,usually refers to the cultivated rice type that can grow normally in sloping land,boundless dry land and arid environment.Under the double pressure of natural selection and artificial selection,upland rice has evolved from common wild rice（Oryza rufipogon Griff.）to form an ecotype different from paddy rice.There is a great correlation between upland adaptation of upland rice and yield formation,moreover,grain weight is one of the important factors of yield component and a vital domestication trait in rice.In this study,phenotypic data of yield related traits of 167paddy rice and upland rice were collected,disposed,analyzed and summarized.Then the genome-wide association analysis was conducted on 1000-seed weight traits of the experiment materials to find the 1000-seed weight locus and candidate genes related to upland adaptation of upland rice.The main results are as follows:1.The effective panicle and the number of grains per panicle were the main factors leading to the significant difference in yield per plant between paddy rice and upland rice.Under dryland condition,the 1000-grain weight of upland rice was significantly higher than that of paddy rice,so the yield per plant of upland rice was significantly higher than that of paddy rice.It could be seen that under dryland condition,1000-grain weight was an important factor of yield difference between paddy and upland rice.2.The 1000-grain weight of OsNced2^T/OsTb2^Cupland rice adapted to dryland condition was significantly higher than that of OsNced2^Cpaddy/upland rice and OsTb2T paddy/upland rice.It was speculated that under the dual pressure of natural selection and artificial selection,upland rice increases its yield by increasing grain weight,thus showing adaptation to upland environment.3.A stable site significantly related to 1000-grain weight was located in the13.92-14.22 Mb region of chromosome 5 by genome-wide association analysis.Then annotations,expression prediction and haplotype analysis were carried out on the genes in the candidate region,Os05g0307200 and Os05g0307400 were finally identified as the key candidate genes in this study.To sum up,under the upland environment,1000-grain weight was an important factor in regulating the yield of upland rice,and it was also an important factor for upland rice to increase yield by increasing 1000-grain weight,thus showing adaptability to upland environment.In this study,through genome-wide association analysis,qUAR1,a stable loci significantly related to the genetic variation of 1000-grain weight between paddy rice and upland rice,and two key candidate genes Os05g0307200 and Os05g0307400,affecting grain weight,were screened,which provided theoretical reference for subsequent upland adaptation research.