Comparison of genetic diversity of the germplasm resources of confectionary sunflower (Helianthus annuus) in China based on RAPDs and AFLPs

RAPDs and AFLPs were used to determine the genetic relationships among 23 elite cultivars of confectionary sunflowers (Helianthas annuus) from different districts in China. Both approaches uniquely fingerprint each of the accessions. Twenty-six RAPD primers resulted in a total of 192 strong DNA fragments, ranging from 0.26 kb to 1.98 kb, among which 165 (86.12%) were polymorphic. The average number of DNA band produced by each primer was 7.38. A total of 576 AFLP markers were produced with 8 primer combinations, ranging from 100 bp to 500 bp, and 341 polymorphic bands (59.20%) were revealed. The polymorphism rate was 76.00% and the average bands amplified by per primer combination were 72. Effective number of alleles per locus of RAPD marker (1.76) was larger than that of the AFLP marker (1.65). The mean PIC value of AFLP markers (0.38) was lower than that of the RAPD markers (0.41), but AFLP marker had much higher Ai value (38.52) than RAPD marker (6.38). Genetic similarities from RAPD data ranged from 47.84% to 82.06% and the average Nei's coefficient was 0.649 5; the Nei's coefficient of similarity from AFLP data ranged from 54.15% to 83.52%, and the average Nei's coefficient was 0.688 4. However, standard deviation (SD) of RAPDs was 0.13 but the SD of AFLPs was 0.08. In general, the RAPD data gave lower similarity values and higher SD values than those based on the AFLP analysis. The correlation coefficient between the two genetic similarity matrices was 0.51, revealing the estimations of genetic relationship provided by the two marker systems were only moderate. However, cluster analyses of RAPD or AFLP data divided the 23 sunflower genotypes into identical 3 groups.