Genome-wide Association Analysis And Candidate Gene Prediction Of Plant Architecture Related Traits In Maize

Maize(Zea mays L.)plays an important role and occupies a significant position in China and even in the world.However,the current maize lodging restricts the target requirements of high and stable yield.Some studies have shown that lodging is closely related to maize plant architecture,so it is necessary to understand the genetic mechanism of maize plant architecture-related traits.In this study,241 maize inbred lines with a wide genetic background were used as materials.The above maize inbred lines were planted in Baoshan City and Kunming City of Yunnan Province from 2017 to 2021.The genotype of the inbred line population was analyzed by Affymetrix SNP 56 K chip technology.Considering the population structure and genetic relationship,the genome-wide association analysis of six maize plant traits was carried out in order to obtain the candidate genes for plant traits and provide the basis for subsequent variety improvement.The main results of this study are as follows:1.In this study,the phenotypic data of 241 maize inbred lines showed normal distribution,which was consistent with the genetic characteristics of quantitative traits.Plant Height(PH),Ear Height(EH)and Ear Height Coefficient(EHC)were consistent in different years,and the data of maize inbred lines from CIMMYT and Thailand were higher than those from China and the United States under the same environment.The Stem Diameter(SD),Total Leaf Number(TLN)and Leaf Number Above Ear(LNAE)of only one year data also showed the same trend.2.Genome-wide association analysis was performed using the previously screened20586 high-quality SNP markers and phenotypic data.Under the dominance level P≤0.001(-lgP≥3),a total of 174 SNP markers associated with plant architecture traits were detected.There were 39 significant loci in PH,44 significant loci in EH,49 significant loci in EHC,12 significant loci in SD,20 significant loci in TLN and 10 significant loci in LNAE.Combined with Gramene website and previous studies,most of these dominant SNP loci detected in this study were located in the reported QTL interval,which proved that these loci were hot spots in plant architecture traits research.3.The effect value of the detected significant loci and its distribution in the research materials were analyzed.The results showed that there were 5 inbred lines covering all negative effect loci in PH,9 inbred lines covering all the negative effect loci in EH,14 inbred lines covered all positive effect sites and 8 inbred lines covered all negative effect sites for EHC,2 inbred lines covering all positive effect sites and 7 inbred lines covering all negative effect sites in SD,one inbred line covered all positive effect sites and the other inbred line covered all negative effect sites in the TLN,2 inbred lines covering all positive effect loci and 12 inbred lines covering all negative effect loci in the LNAE.These materials can be used for directional improvement of maize plant architecture related traits.4.A total of 12 candidate genes related to plant architecture traits of maize were excavated through gene annotation and gene function screening within 200 kb upstream and downstream of the detected dominant loci,including 5 candidate genes for PH,4candidate genes for EH,1 candidate gene for EHC,and 2 candidate genes for SD,which laid the foundation for further verification of gene function and genetic improvement.