Submitted to: Sunflower International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/12/2000
Publication Date: N/A
Citation: Interpretive Summary: In constructing a genetic map of a species it is most desirable to cross two parents that are genetically very diverse. Prior to constructing our genetic map of sunflower, we analyzed 23 USDA sunflower lines, both male and female lines to determine their similarities, with the intent to use the most dissimilar lines as parents of a cross to be used for mapping. We found that the similarity values between lines varied from a low similarity of 0.33 (RHA271-HA234) to a high similarity of 0.82 (HA89- HA852). The RHA271 x HA234 was therefore selected for our RFLP mapping effort. Most of the similarities were between 0.40 and 0.60, indicating that the 23 USDA lines represented good sunflower germplasm diversity.
Technical Abstract: Since USDA released germplasm lines have been used widely by breeders all over the world, we decided to evaluate their genetic diversity before approaching the construction of our public RFLP linkage map for cultivated sunflower. The similarity matrix of the 23 lines showed that, with the exception of 0.99 between HA822 and cms HA822, the similarity values varied from 0.33 (RHA271-HA234) to 0.82 (HA89-HA852). The RHA271 x HA234 was therefore selected for our RFLP mapping effort. HA822 and cmsHA822 were used as internal checks and the results indicated a nearly identical pattern for all the alleles examined. The 1101 alleles were detected by 304 probes and averaged to 3.6 alleles per probe. The average similarity index among all the lines was 0.49, excluding that between HA822 and cmsHA822. In general, the majority of the similarities were between 0.40 and 0.60, indicating the good diversity of the representative USDA germplasm lines. The average similarity index was 0.46 for RHA-HA lines, 0.54 for RHA-RHA lines, and 0.52 for HA-HA lines. Results suggested the need of further diversification within and between RHA and HA lines for stronger hybrid vigor and higher hybrid yield in the future.