Analysis Of High-yield Assemblage Pattern Of Hybrid Soybean Based On Core Parents Re-sequencing

In the practice of crop hybrid breeding,one of the methods to realize the creation of strong-dominant hybrids is to use the theory of heterotic groups to select parents in different heterotic groups for combination preparation.Therefore,establishing the corresponding heterosis pattern can provide theoretical guidance for the rational combination and effective utilization of crop hybrid parents.Some major crops such as corn,rice,and wheat have been divided into heterotic groups,established corresponding heterosis patterns,and successfully applied to the practice of hybrid breeding,which has greatly improved the efficiency of hybrid combination and accelerated the breeding process of strong hybrids.In contrast,although the utilization of soybean heterosis has been carried out for more than 30 years,and a number of hybrid soybean varieties have been bred and approved,due to the lack of relevant research on soybean heterosis groups,researchers only use breeding experience to make combination preparations,resulting in combined preparation.The yield rate is less than 2%.Although predecessors have used molecular markers to carry out some studies on the genetic diversity of hybrid soybean parents,due to the limitations of molecular marker polymorphism and coverage,it is difficult to accurately classify groups,and efficient assembly methods have not yet been proposed.With the rapid development of high-throughput sequencing,whole-genome re-sequencing,as an important means of comprehensively analyzing gene variation sites,has also been gradually applied to the classification of crop heterotic groups,which has significantly improved the accuracy of heterotic group classification.In this study,38 hybrid soybean core parents were used as materials,including 14 restorer lines,24 sterile lines or maintainer lines.Whole-genome re-sequencing technology was used to mine the genetic variation sites of the parent materials,and to analyze the genetic diversity and heterosis.Classification of taxa,combined with the yield data of 76 combinations obtained from incomplete dialectical crosses over the years,the following conclusions were obtained.:(1)Completed the whole genome re-sequencing of 38 hybrid soybean core parents,and filtered and compared the original high-throughput sequencing data.The average comparison rate of all parents reached 97.26%,and the average sequencing depth of the genome reached9.4×.The average coverage is 94%.The reference genomes of the above samples all meet the re-sequencing requirements,with good coverage depth and coverage,and can be used for subsequent analysis;(2)Using GATK software to detect,obtained 6,833,932 SNPs in the population,continue to detect polymorphic sites in the population,and filter the obtained SNPs based on specific filtering conditions,and get 1,258,603 SNPs;(3)The 38 parental SNPs datasets were used to calculate the distances between various groups,and the phylogenetic tree of the parental materials was constructed by the neighbor-joining method,and the parental materials were divided into two main groups,most of which belonged to Northeast China in group I.materials,accounting for 86.21%;group II is mainly American materials,accounting for 66.67%,and the rest are Chinese and American mixed blood materials.In addition,group I can be divided into 7 subgroups,indicating that the genetic diversity of the core parents is relatively rich;(4)Principal component analysis was further carried out on the 38 core parents,and the clustering results and the phylogenetic tree grouping results were verified by each other.;(5)Heterosis analysis was carried out on the yield data of the parental preparation combinations between the two groups,and the results showed that heterosis generally existed in F1,and there were great differences between different combinations.The descendants of the Northeast China material×foreign material combination formula have significant advantages in yield.Among the strong dominant combinations identified,China × American combination accounted for the highest proportion and the dominance rate was higher than other combinations,showing stronger heterosis.Based on the above analysis results,it is preliminarily proposed that the high-yield assemblage pattern of Northeast China materials×American materials is based on different taxa or subgroups.