Heterosis Prediction Of Sweet Corn Base On SSR Molecular Marker

In this study,the genetic polymorphisms of 8 parentinbred lines and 28 progenies(F1generation)of sweet maize were analyzed by using the agronomic traits and SSR molecular markers.The clustering and principal component analysis were used to calculate the average heterosis,heterobeltiosis and heterosis index to evaluate the genetic diversity and heterosis of maize core germplasm.The results were as follows:1.Based on the cluster analysis of agronomic traits,the parentinbred lines could be divided into two groups.The first group included seven parents and the second group had only one parent.The first group included two supgroups,the first subgroup included P2,P4,P6 and P8,and the second subgroup included P1,P3 and P7.There was only P5 in the second group.Overall,parent P5 was more different from the other parents genetically.2,Ten SSR primers were used to amplify the genomic DNA of the parents and their progenies,and 54 loci in total were observed by SSR markers.all the loci were polymorphic.The high genetic diversity were found in the parents and progenies.Based on cluster analysis of SSR molecular markers,all individuals were divided into six groups,the sixth group was divided into four subgroups,one of which had five parents,and there was little genetic difference between P1 and P7.The second group consisted of two parents(P2and P3).The fifth group contained P8,with more significant genetic difference between P5 and other several parents.There was larger genetic distance among the F1 progenies,so F1 generation enlarged the difference from the parental generation.3,Twelve agronomic traits and their variation from the F1 generation were higher than those from the parental generation.According to the analysis of the average superiority,the super superiority and the heterosis index,most of F1 generation were superior to their parents in positive advantage.4,The genetic distance between P5 and P8 was the highest,and the agronomic traits of P5 and P8 were the highest in the mean superiority analysis,while the genetic traits of F1-25(cross between P2 and P7)with a certain genetic distance showed a negative average advantage,indicating that differences of SSR molecular markers and agronomic traits could predict heterosis to some extant,but the heterosis was incompletely correlated with the genetic distance.