玉米氮利用效率全基因组关联分析及候选基因挖掘OA

Nitrogen is a key factor influencing maize yield.To dissect the genetic basis of nitrogen response in maize,this study utilized a natural population consisting of 312 maize inbred lines and employed genome-wide association analysis(GWAS)on the nitrogen response index(NRI)of yield-related traits.The results indicated that yield-related traits exhibited abundant phenotypic variation under both nitrogen conditions.Significant differences in nitrogen response index of grain yield(NRIGY)and grain yield were observed among different heterotic groups;compared with other groups,the Iodent group displayed the highest NRIGY,while the SPT group exhibited the strongest low-nitrogen tolerance.Genome-wide association analysis identified a total of 1582 significant loci associated with NRI,of which 352 loci were located within the confidence intervals of previously reported nitro-gen-efficient QTLs.These significantly associated loci comprised 372 candidate genes,primarily involved in maize growth,de-velopment,and stress responses.Haplotype analysis of key candidate genes revealed that,the TT haplotype of Zm00001d021701 had a lower nitrogen response coefficient for kernel number per row than CC,but exhibited higher yield than CC under both nor-mal and low nitrogen conditions;the AA haplotype of Zm00001d037229 had a higher nitrogen response coefficient for ear height than GG,and outperformed GG in yield under both nitrogen levels.This study systematically elucidated the genetic architecture of nitrogen response in maize,and the identified key candidate genes along with their elite haplotypes provide important genetic resources and theoretical support for molecular breeding of nitrogen-efficient maize varieties.