Genetic Diversity Analysis Of Marigold(Tagetes Erecta L.) Two-lines With Dwarf And Hybrid Offspring

In this study,15 dwarf marigold male sterile lines,17 marigold hybrid parents(including some dwarf two-lines)and 15 marigold hybrids were used as materials.Use SSR molecular markers and morphological markers to explore the genetic diversity between dwarf two-lines and between hybrid generations.And further comprehensive evaluation of the dwarf two-lines,explore the genetic relationship between the first hybrid and the paren ts,and provide a theoretical basis for the breeding of the short two-lines and the first hybrid with excellent traits,and the breeding of two-lines.The main research results are as follows:1.According to the pre-flowering period and the blooming time of the group flowers,the 15 short-stem dual-purpose lines are divided into early-flowering long-flowering lines(C-4,C-10)and medium-flowering long-flowering lines(C-3,C-5).,C-8,C-9)Medium-flower type and medium-long-flowering line(C-20),late-flowering type and medium-long-flowering line(D-1,D-3,C-6,C-12),late-flowering type Short-flowering line(C-1,C-7,C-14),late-flowering long-flowering line(C-11).By comparing the morphological indicators,it was found that the morphological differences of the 15 dual-purpose lines were mainly reflected in the flower diameter and plant height.Among the quantitative traits,there are 5 pairs of traits(plant height and number of first-level branches,plant height and number of flowers,crown width and number of first-level branches,plant height and crown width,crown width and number of flowers)that are significant or extremely Significantly positive correlation;among the quality traits,there are 6 pairs of traits(the top traits of lingual florets and petal types,the top traits of lingual florets and the number of lingual florets,the number of lingual florets and the type of petals,the top traits of lingual florets and the type of Small flower type,petal type and small flower type)are signific antly or extremely significantly positively correlated.Through the cluster analysis of the phenotypic traits of 15 dwarf dual-use lines,it can be divided into 3categories,and 3 dwarf dual-use lines with excellent overall phenotypic traits have been screened,namely C-9,C-14 and C-12.The above analysis lays the foundation for the selection,evaluation and understanding of the genetic relationship of short dual-purpose lines.2.Screen out 8 pairs of primers from 48 pairs of primers that can stably amplify polymorphic primers with clear bands.The polymorphism ratio of primer amplification was 95%,and the average number of alleles per locus was 2.45.The Shannon information index is 0.5834,and the polymorphic information content is 0.304.The polymorp hic information content of the selected markers can meet the genetic diversity analysis of the tested materials.The tested materials have relatively rich genetic diversity,and the UPGMA cluster analysis results are consistent with the principal coordinat e analysis results.In addition,the molecular fingerprints of 15 short dual-use lines were constructed using SSR markers,which provided a basis for the identification and utilization of 15 short dual-use lines.3.The morphological differences of the 15 hybrid generations are mainly reflected in plant height and crown width.Cluster analysis divided 15 marigold germplasm resources into 5 categories.Different types of marigolds are classified based on the difference in plant height.The 15 hybrid generations have different degrees of comprehensive super-parental dominance and comprehensive mid-parental dominance.For hybrid generations with higher super-parental dominance and mid-parent dominance(such as Combination 5 and Combination 18),they can focus o n and apply them later.The genetic distance of the 15 hybrid generation populations was0.0645-0.7332,and the average genetic distance was 0.402.The genetic difference was relatively large,and the genetic diversity level between the hybrid generation was relatively high.The clustering results among Popgene populations show that the hybrid generation is more inclined to paternal inheritance.The analysis of F statistics shows that the average Fst is 0.0519,which indicates that the genetic variation of marigold population mainly comes from within the population(94.8%),and the genetic differentiation between populations is very small.