ABSTRACT
Objective:To explore the genetic diversity and population structure of <italic>Erigeron breviscapus</italic>， so as to provide a scientific basis for its resource protection and rational utilization. Method:Twelve pairs of simple sequence repeat（SSR） primers were screened out from 243 individuals in 16 natural populations to calculate the genetic diversity parameters of <italic>E. breviscapus</italic>， which were then subjected to principal coordinate analysis and cluster analysis. Result:Twelve SSR markers generated 209 alleles， with an average of 17.417 alleles per locus. Based on 12 SSR markers and 16 populations of <italic>E. breviscapus</italic>， the observed heterozygosity （<italic>H</italic><sub>0</sub>） values were determined to be 0.603 and 0.613， the expected heterozygosity （<italic>H</italic><sub>e</sub>）to be 0.658 and 0.659， and the Shannon's information index （<italic>I</italic>） to be 1.443 and 1.446， respectively. The Wright's fixation index （<italic>F</italic><sub>st</sub>） was 0.123 and gene flow （<italic>N</italic><sub>m</sub>） was 2.077. Analysis of molecular variance （AMOVA） and genetic differentiation revealed that genetic variation within populations was the main source of total variation. The Nei's genetic distance and genetic identity coefficients were within the ranges of 0.107 （YA and XY）-0.713 （SZ and XZD） and 0.490 （SZ and XZD）-0.899 （YA and XY）， respectively. As demonstrated by the principal coordinate analysis and cluster analysis， the 16 populations of <italic>breviscapus </italic>were divided into two clusters. Conclusion:The genetic diversity of <italic>E. breviscapus</italic> was relatively high and there existed certain genetic differentiation and gene flow within and among populations. The genetic variation was mainly present within populations. All these have provided reference for subsequent study on good germplasm selection of <italic>E. breviscapus.</italic>
ABSTRACT
Aim: The present study was undertaken to examine the relation between genetic divergence of some tropical inbred lines of maize and extent of heterosis manifestation in their single cross hybrids. Methodology: Fifteen inbred lines and three inbred testers along with 45 single cross hybrids were evaluated by adopting randomized complete block design during two seasons. The observations recorded on eight metric traits of the entries in each of three replications were utilized during statistical analysis across the seasons. Relative importance of classification variables was determined by principal component analysis and the phenogram was generated using average taxonomic distance. Molecular profiling of inbred lines was carried out by employing 28 SSR primer pairs covering all the chromosomes. Principal coordinate analysis was performed and similarity indices based dendrogram was constructed. Relationship between parental genetic divergence and heterosis was statistically tested. Results: Significant differences due to parents, hybrids and parent vs. hybrids were observed for all metric characters. Principal component analysis based diagram and average taxonomic distance based phenogram separated the inbred lines into five clusters. Amplification profiles based principal coordinate analysis and hierarchical cluster analysis differentiated the inbred lines into four major clusters. Statistically non-significant correlation of genomic data based genetic similarity or phenotypic data based genetic dissimilarity of inbreds was revealed with grain yield and heterosis of hybrid combinations. Significantly positive correlation was found between heterosis over mid parent or better parent and grain yield of hybrids. Interpretation: Parental genetic divergence was not linearly or additively related to heterosis manifestation in hybrid. Moderate genetic divergence together with high per se performance of inbreds seemed to be a better criterion than consideration of merely extreme genetic diversity as the basis for the choice of parental inbreds during heterotic single cross hybrid development in maize
ABSTRACT
ABSTRACT Amorphophallus (elephant foot yam) is an herbaceous edible aroid crop which belongs to the family Araceae. The study was undertaken to identify the efficient SSR primer that could differentiate a set of 12 elephant foot yam genotypes. Various efficiency parameters, namely, Polymorphism Information Content (PIC), Marker Index (MI), Resolving Power (RP) and Diversity Index (DI) were studied for 11 primers. The relationship between the parameters was studied using Spearman rank correlation coefficient. Discrimination analysis was done to find out the most effective parameter. Finally Principal Coordinate Analysis (PCoA) and dendrogram was done to find out the genetic diversity among the germplasm. The SSR markers under this investigation will facilitate further studies in population genetics and utilization of A. paeoniifolius.
ABSTRACT
Objective: To analyze the genetic diversity of Panax japonicus var. major by inter simple sequence repeat (ISSR) molecular makers. Methods: Genetic diversity of 19 samples from main production areas was investigated by ISSR and analyzed by principal coordinate analysis and UPGMA cluster analysis. Results: A total of 181 bands were generated by 13 ISSR primers, among which 166 bands (91.71%) were polymorphic bands (PPB). The coefficient of genetic similarity ranged from 0.60 to 0.83. The results of UPGMA cluster analysis and principal coordinate analysis showed that the genetic diversity of P. japonicus var. major from the same region presented a geographical distribution regularity. Conclusion: The results of ISSR analysis reveals that P. japonicus var. major has a high genetic diversity level and the genetic relationship closely contacts with the geographical location.