Submitted to: Acta Botanica Sinica
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2002
Publication Date: 3/1/2003
Citation: LIU, J., LIU, G.-S., JAN, C.C. COMPARISON OF GENETIC DIVERSITY OF THE GERMPLASM RESOURCES OF CONFECTIONARY SUNFLOWER (HELIANTHUS ANNUUS) IN CHINA BASED ON RAPDS AND AFLPS. ACTA BOTANICA SINICA. 2003. V 45 (3). P.352-358. Interpretive Summary: Sunflower (Helianthus annuus L.) is an important source of plant lipid and protein. Appraisement on germplasm resource is very important in breeding programs. Although many methods were used in estimating genetic diversity in early research based on morphological, physiological and biochemical data, all appeared to have obvious limitation. Most of them were unreliable due to the phenotypic variation and not sufficient loci with biochemical data. Molecular markers, such as RFLP, RAPD, AFLP and SSR etc., can be detected readily throughout plant genomes, providing discrete data that are less ambiguous than many other types of data, and can be readily used for statistical analysis. Sunflower molecular markers have been used to determine genetic differences among oilseed sunflower. However, most of the reports were focused on the wild or oilseed sunflower and little information is available about the genetic diversity of the confectionery sunflower. In this report, 23 elite confectionary sunflower varieties were evaluated based on the RAPD and AFLP data. Considerable variation among the 23 confectionary sunflowers at the genomic DNA level is detectable with AFLP markers. Although the level of polymorphism offered by AFLPs was lower than RAPDs, AFLPs are the most efficient because they have the capacity to reveal many polymorphic bands in a single lane. Therefore, RAPD or AFLP markers could clearly separate the genotypes of confectionary sunflower into heterotic groups and detect pedigree relationship among them. Additionally, the lower degree of genetic similarity and larger diversity scale among the 23 genotypes indicated that there were abundant genetic diversity among these varieties of confectionary sunflower in China.
Technical Abstract: RAPDs and AFLPs were used to determine the genetic relationships among 23 elite cultivars of confectionary sunflower 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 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 (59.2%) were revealed. The polymorphism rate was 76.0% 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 more 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 0.6495; the Nei¿s coefficient of similarity from AFLP data ranged from 54.15% to 83.52%, and the average Nei¿s coefficient was 0.6884. 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 relatedness 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.