Genetic Diversity Of Carya Illinoensis Germplasm

In this study, two kinds of molecular markers, ISSR and SRAP were used to assess geneticdiversity and relationship of163accessions of Carya illinoensis, by establishing the phylogeneticrelationship trees. The information obtained would provided theoretical and genetic basis fordividing Carya illinoensis through genetic correlation analysis. Results are summarized are asfollows:1. Optimized ISSR, and SRAP reaction systems.ISSR reaction mixtures had a total volume of25μL, which contained5μL10×buffer (Mg2+free),0.625U Taq DNA polymerase,0.4mmol·L-1dNTP (Mg2+plus),0.8μmol·L-1primer and40ng template DNA, the shortfall used ddH2O to make up.SRAP reaction mixtures had a total volume of20μL, which contained2.5μL10×buffer(Mg2+free),1.0UTaqDNA polymerase,0.2mmol·L-1dNTP, Mg2+2.0mmol/L,0.4μmol·L-1primerand60ng template DNA.2. Fourteen ISSR primers from100ISSR random primers and8pair primers from88pairsSRAP primers were selected for the analysis of genetic diversity accessions of Carya illinoensis.A total of56bands were amplified by ISSR primers, in which55bands were polymorphicbands.Each primer produced7polymorphic loci on average.98%were polymorphic band. Atotal of79bands were amplified with8pairs of SRAP primers, with each pair of primersproduced9polymorphic loci on average. Of which,72bands (93.13%) were polymorphic. Thesetwo markers had high conformity to the genetic correlation analysis of Carya illinoensis.3. The similarity coefficients of ISSR and SRAP ranged from0.29~0.94and0.57~0.99respectively. It suggested that, genetic background was complicated and varied;depending on the phylogenetic relationships. However, samples from the same family alwaysclustered into one group, suggesting their close genetic relationship.4. Correlations of the genetic similarity matrix among. ISSR,. SRAP and the synthesis datawere high, indicating that the two methods have high, consistency in revealing genetic diversityof Carya illinoensis. However, data obtained suggest that SRAP technique was more reliable thanother techniques tested.5. All samples in this study were taken from artificially built groups, rather than naturalpopulations. Therefore, the reproductive modes and manual intervention may be, factors havethat influenced genetic degree differentiation.