Location: Sugarcane ResearchTitle: Genetic structure and diversity of parental cultivars involved in China mainland sugarcane breeding programs as inferred from DNA microsatellites Author
Submitted to: Journal of Integrative Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/27/2011
Publication Date: 11/1/2012
Citation: Qi, Y., Pan, Y.-B., Lao, F., Zhang, C., He, H., Fan, L., Liu, R., Wang, Q., Liu, S., Liu, F., Li, Q., Deng, H. 2012. Genetic structure and diversity of parental cultivars involved in China mainland sugarcane breeding programs as inferred from DNA microsatellites. Journal of Integrative Agriculture. 11(11):1794-1803. Interpretive Summary: All sugarcane breeding programs worldwide have field nurseries to maintain important cultivars, breeding lines, and clones of foreign introductions for the source of parental material for crossing. How to utilize the nursery material effectively is a major issue, especially when dealing with a limited resource. In this study, the distribution of 18 microsatellite DNA markers among 96 proven parental sugarcane clones was investigated and the resulting data was analyzed to assess the extent of genetic diversity and population structure. The results showed that there were five distinctive genetic groups within the 96 clones based on species, country of origin and breeding value. Groups 1, 2, 4, and 5 consisted of sugarcane cultivars while Group 3 contained wild species only. For the cultivar groups, Group 2 had 46 cultivars predominantly from Australia, China Taiwan, India, and USA, while Groups 1, 4, and 5 had 37 cultivars from China Mainland. A particular finding was that the “Yacheng” breeding clones with genetic component of native Chinese wild species had substantially broadened the genetic base of the Chinese sugarcane cultivars. By understanding the genetic relationship of the key parental clones, sugarcane breeders gain a rational basis for further expanding the gene pool, promoting cultivar exchange activity, and selecting the best parental clones for crossing.
Technical Abstract: More than 1,400 Saccharum accessions of worldwide origin were available in the Chinese sugarcane breeding program, but the genetic diversity and population structure of these accessions has not been fully investigated. In this study, 96 proven important parental accessions of various geographical origins were genotyped with 18 microsatellites to investigate their genetic relationship. This study showed that the number of alleles per locus ranged from 7 to 31 with an average of 16.8. Model-based structure, clustering, and principal components analyses consistently indicated that there were five groups within the 96 accessions as determined by species, geographical origin and breeding value. Among the five groups, Groups 1, 2, 4, and 5 consisted of cultivars while Group 3 contained wild germplasm exclusively. For the cultivar groups, Group 2 had 46 cultivars predominantly from Australia, China Taiwan, India, and USA, while Groups 1, 4, and 5 had 37 cultivars from China Mainland. This study indicated that obvious genetic difference existed among the accessions of different origins. In particular, the “Yacheng” lines developed through introgression from native Chinese S. spontaneum germplasm have substantially broadened the genetic base of cultivars. By understanding the genetic diversity and population structure of key parental accessions, breeders gain a rational basis for further expanding the gene pool and selecting the best parental accessions for crossing.