Genome-wide Association Analysis On Heterosis Of Agronomic Traits Of Partial Interspecific Hybrids Between Oryza Sativa L. And Oryza Glaberrima Stued.

Fifty rice lines containing genomic genes of African rice,including NERICA rice and introgression lines as well as the partial interspecific hybrid rice produced by crossing the 50 lines with a common rice variety,shengtai No.1,were used as experimental materials for this study.Eleven agronomic traits(including rice seed setting rate,effective panicles per plant and thousand seed weight,etc)were evaluated.Reduced-Representation Genome Sequencing(RRGS)was conducted for the parental lines.Genome-wide associationthe analysis(GWAS)was made on the data of the agronomic traits of the patental lines and the heterosis of hybrids.The aim is to develop molecular markers and to provide theoretical and practical basis for further breeding of new partial interspecific hybrid rice varieties with good agronomic traits and strong heterosis.The main results are as follow:1.The agronomic traits of the parental lines and the heterosis of the test crossed hybrids were evaluated in Hainan and Wuhan,respectively.The results showed that the partial interspecific hybrids F51,F55,F57,F59,F69,F81 and F83 showed relatively prominent heterosis in Wuhan,while the hybrids F9,F31,F57,F63,F83,F91,F17-1were better in Hainan;Two hybrids F57 and F83 had outstanding performance in both locations.2.Statistic analysis on the output data of 50 DNA samples of the parental lines show that all of them reached the clean data quality standards(each sample clean data not less than 0.52G).The clean data does not contain reads with low quality base(Q ≦20)accounted for more than 20%.The quality of sequencing reached a relatively high level(all qualified samples Q20 above 99%,with GC content around 40%,mapped rates of most samples over 95%,and coverages of about 15%).3.Population structure analysis of the 50 materials indicated they are divided into four groups.Group 1 contains NERICA rice.Group2,3,and 4 were introgression lines.Using the seed setting rate,1000-grain weight,effective panicle number,yield per plant and grains per spike as the main reference,multiple comparison was made between the agronomic traits of the groups.The results showed the performance in Hainan were Group4> Group2> Group3> Group1,while those in Wuhan were Group4> Group3> Group2> Group1.All introgression lines of Group2,3 and 4 had better performance than the NERICA rice of Group1 in both Hainan and Wuhan.Group4 is the best introgression lines.4.Using a mixed linear model,genome-wide association analysis was performed on the11 agronomic traits of 50 rice parental materials.A total of 27 QTLs(q GL-1-2,q LWR-3-1,q TWG-1,q DSH-1,q SL-7,q GNPS-6,q SSR-7,etc)related to seven agronomic traits(GL,LWR,TWG,DSH,SL,GNPS and SSR)were detected on 9chromosomes(Chr1,Chr2,Chr3,Chr5,Chr6,Chr7,Chr8,Chr9 and Chr11).5.Using a mixed linear model,genome-wide association analysis was performed on the heterosis of 11 agronomic traits of 50 test-crossed hybrids.A total of 23 HLs(h SL-1,h PH-2,h LWR-1,h GL-5,etc)related to the heterosis of four agronomic traits(GL,LWR,SL and PH)were detected on 9 chromosomes(Chr1,Chr2,Chr3,Chr4,Chr5,Chr8,Chr9,Chr11 and Chr12).