Study On Heterotic Grouping Of Inbred Lines Based On SSR Markers In Maize (Zea Mays L.)

The proper grouping of maize inbred lines and establish corresponding heteroticpatterns are important in maize breeding. SSR molecular markers is a powerful tool toanalyze the maize genetic diversity, the germplasm could be divided into differentheterotic groups which could provide a theoretical basis for the breeding of elitehybrids. In our study used six standard test species and11backbone inbred lines ofknown populations,70SSR markers which were Selected from the maize genetic andgenomic databases and distributed evenly on the10chromosome were used for thegenetic diversity analysis of79unknown population maize inbred lines, the mainresults were as follows:1.223polymorphic amplified fragments could be amplified in96maize inbredlines using70SSR markers the average allele number per SSR locus was3.61witha range from2to5, the polymorphism information content (PIC) for the SSR locivaried from0.153to0.787with an average value of0.60. Genetic similarities amongthe96inbred lines ranged from0.497to0.919with an average of0.640.2. The clustering and principal coordinate analysis was conducted usingUPGMA method,96maize inbred lines were classified into2groups of SS and NSSthat including6subgroups.47maize inbred lines belonged to Reid, PA and LRCsubgroup could be united to SS group, and the other49maize inbred lines belonged toPB, SPT and Lancaster subgroup could be united to NSS group. The inbred lineQ895-2was so close with its sister line Q895-3in genetic distance belonged to thesame group. In addition, eleven inbred lines which had clear heterotic groupascription were divided into appropriate groups.3. The population structure of96maize inbred lines were analyzed usingStructure2.3.1software, the results showed that the most appropriate K value was six,which meaned the target group could be devided into six subgroups. The populationgenetic structure was evaluated using Q-matrix,74inbred lines definitely belonged toSS or NSS heterotic groups(Q-value>0.6),5inbred lines showed a scatteredascription (Q-value<0.6) were mainly due to the presence of gene flow in differentgroups.