Genome-wide Association Study With Resistance To The Asian Corn Borer In Maize

Maize(Zea mays L.)is an important food and fodder crop,and insect damage is a crucial factor affecting the yield and quality of maize.Corn borer is the main insect,and Asian corn borer is the most serious insect in China.Chemical methods are used to prevent and control pests in maize production,but they are easy to cause environmental pollution and do harm to human and animal health.Therefore,screening the insect-resistant maize and cultivate the insect-resistant varieties is a key way to prevent and control the Asian corn borer.In this study,301 maize inbred lines are used to the test,through field insect infection and phenotype identification,evaluation of different resistance of maize inbred lines of Asian corn borer,using the mixed linear model analysis of genome-wide association analysis to obtain insect-resistant genes and loci,provides a theoretical basis for the improvement and breeding of insect-resistant maize.The main results are as follows:1.Phenotype identification of corn borer resistance in 301 maize inbred lines.The results indicated that the maize inbred lines showed different levels of insect resistance.Leaf damage,stem tunnel length approximately normally distributed in the selected population,leaf damage distribution at level 4 to 7,decayed stem tunnel length distribution at 0.1cm to 4cm,the proportion of high resistant and high sensitive inbred lines is small.There is no significant correlation between leaf damage and the length of stem tunnel.It meant that the two traits might be controlled by different genes.2.Based on 994232 SNPs which uniform distribution in the maize genome,using the mixed linear model for the genome-wide association analysis,28 SNPs were found significantly associated with tunnel length of stem in 2015.These SNPs distributed in 10 chromosomes in the maize genome.Using B73 genome sequence as a reference,candidate genes were found in the upstream and downstream 2000 bp of significant loci,and 8 candidate genes were obtained.Among them,AC234521.1_FG006(encoding TCP transcription factor)and GRMZM2G123202(encoding MYB transcription factor)may indirectly participate in plant resistance in terms of hormone level regulation and other aspects.3.Combined with the existing research on the insect resistance,the significant SNPs which were located in this study,were near those of previous studies on the physical distance of three insect-resistant genes,namely rs749218,rs747464 and rs747701,which are similar to the genes related to the synthesis of DIMBOA,as well as rs665864 similar to GRMZM2G389097.SNPs located in the previously reported insect-resistant QTL region including rs913137?rs928354?rs747464?rs747701?rs749218?rs298342 and rs44064.The reliability of these sites was further determined and laid a certain foundation for future research.