Population structure and association mapping studies for yield-related traits in Maize (Zea mays L.)

Association mapping is an efficient approach for dissecting the genetic architecture of yield-related traits using single nucleotide polymorphism (SNP) markers in maize. The present study was carried out with a set of 93 diverse maize accessions with the objectives of analysing the population structure and conducting association mapping between SNP markers and yield-related traits viz. number of kernel rows per ear (NKR), number of kernel columns per ear (NKC), 100 grain weight (HGW) and grain yield (GY). Illumina golden gate assay containing 1536 SNPs distributed in all the chromosomes were used for genotyping 93 maize accessions. The population structure studies depicted the presence of five subpopulations, named ZM1, ZM2, ZM3, ZM4 and ZM5, contained 21, 16, 19, 12 and 25 accessions, respectively. Association mapping analysis carried out using mixed linear model (MLM), which is identified 36 marker-trait associations (MTAs) in the two years. Of these, 26 MTAs were detected either nearby or flanking the regions where the genomic regions have been reported. While, remaining 10 MTAs were detected in the novel genomic region. The number of markers associated with each trait ranged from 6 (NKC) to 13 (HGW). We also found that one trait was associated with many markers (e.g., HGW with 13 markers), and single marker was also associated with multiple traits (eg. PZB00114_1 associated with HGW and GY). Our results provide good information for genetic architecture of yield-related traits and associated SNP markers could be valuable in implementing marker assisted selection (MAS) in maize breeding programs.