Genetic Analysis Of Haploid Female Fertility In Maize

Haploid breeding can shorten the breeding period and speed up the breeding process.In-depth study of the genetic mechanism of maize haploid grain setting and panicle traits,and mining of high-quality genes,has practical significance for the establishment of high-throughput DH breeding systems.In this study,based on the F_2:3family constructed from the maize inbred lines B73 and Zheng 58 with significant phenotypes,the F_2:3family haploid was obtained by induction of the inducible line.QTL mapping and Genome selection analysis of natural doubling correlation of haploid female ears in Maize under multiple environments were carried out:（1）The results of phenotypic identification showed that maize haploid Cob length was significantly correlated with Cob diameter,Ear row number,Kernel number per row,Haploid female fertility rate,and Average kernel number.All six traits showed a normal distribution trend,which was in line with quantitative traits.（2）QTL mapping was performed for the natural doubling trait of maize haploid ears,and a total of 48QTL were detected.A total of 11 QTL loci were detected in Cob length,and there was one major locus that was stably inherited in multiple environments on chromosome 1;2 major QTL were located on chromosome 3.A total of 10 QTL loci were detected in Cob diameter,and there was a major locus on chromosome 5 that was stably inherited in multiple environments;Kernel number per row have 4 QTL loci were detected on chromosome 1,which were the main QTL stably inherited in multiple environments,and the phenotypic contribution rate of q KNR1-2m was 29.13%.A total of 7 QTL loci were detected in the rate of Haploid female fertility rate,which were located on chromosome 5 and there were minor QTL that were stably inherited in multiple environments.A total of 16 QTL loci were detected in the Average kernel number,and there were two major QTL stably inherited in multiple environments on chromosome 4.（3）There are 9 QTL clusters with pleiotropic effects among the five traits,and there are 10 clusters of QTL located in bin 1.01 of chromosome 1,which are related to the four traits of cob length,cob diameter,Kernel number per row and Average kernel number.There are 4 QTL loci with an interval length of 4.24Mb,indicating that the four traits are genetically similar and may have the same metabolic pathway and gene control.（4）Candidate genes were predicted for traits related to natural doubling of maize ears,and five important candidate genes,Zm00001d018366,Zm00001d051543,Zm00001d053635,Zm00001d027427and Zm00001d053616,were obtained,which laid the foundation for further functional verification and cloning of grain synthesis genes.（5）The results of Genome selection showed that the prediction accuracy of different reference population sizes was measured,and all achieved relatively high prediction accuracy when the reference population accounted for 50%-60%of the total.The prediction accuracy of different numbers of SNP markers was analyzed,and it was shown that when the number of SNP markers was 500,a relatively high prediction accuracy was achieved.