Submitted to: Sugar Tech
Publication Type: Abstract Only
Publication Acceptance Date: 1/5/2018
Publication Date: 1/19/2018
Citation: Pan, Y-B. 2018. Application of molecular markers in sugarcane germplasm innovation and breeding: new germplasm with cytoplasm from Saccharum spontaneum. Sugar Tech. doi:10.1007/s12355-018-0588-0.
Technical Abstract: All current sugarcane cultivars (Saccharum hybrids spp.) are interspeci'c hybrids of S. of'cinarum, S. robustum and S. spontaneum that bear the same cytoplasm of S. of'cinarum. Until the end of 20th century, S. spontaneum was exclusively used as male parents to confer such traits as vigor, ratoonability, and disease and insect resistance. There was no report on S. spontaneum being used as female parents, due to S. spontaneum being regulated noxious weeds with substantial self-fertilization and vigorous rhizomes. This situation changed when two series of innovative crosses (S. spontaneum x elite cultivars) were made in 1997 and 2001 at the USDA-ARS, SRU. Flowers of S. spontaneum were pretreated by trimming off both dehisced and immature florets, immersing in 45oC (or 50oC) circulating water bath for 10 (or 5) min, and being placed underneath the flowers of elite varieties. The 1997 cross was made between S. spontaneum clone Djatiroto and cultivar LCP 85-384. The 2001 crosses were made between ten S. spontaneum clones and six elite varieties. One F1 progeny from the cross (SES 234A x LCP 85-384) survived a hard frost in March 2003 and was commercially released as an energy cane cultivar Ho 02-113 in 2012. From the 1997 cross, five F1 progenies were selected based on DNA marker and phenotypic evaluations. Their authenticity was further confirmed by SSR fingerprinting. One progeny, US 99-43, produced the largest stalks with the highest Brix values and was chosen for further improvement. Three cycles of backcrossing, field evaluation, and selection were completed by 2017. Seven BC2 progenies were selected in 2008. One BC2 progeny, Ho 08-9504, produced 8 large stalks and a Brix of 23.8. It never flowered in Louisiana, but flowers readily in Florida. A BC3 backcross (Ho 08-9504 x HoCP 04-852) was made at Canal Point, FL, 216 BC3 progenies were planted in the field in 2015, of which 36 were advanced to 1st line trials in 2016. Seven of the 36 BC3 progenies were advanced to 2nd line trials in 2017 that were free of diseases and borers, produced 11-20 stalks with 25-32 mm diameter and 19.6-22.4 Brix. Pedigree indicated that these 7 BC3 progenies may inherit nuclear genes from S. spontaneum, S. robustum, and Erianthus. Availability of these BC3 progenies may enhance genetic diversity analysis of Saccharum germplasm and enable sugarcane breeders to explore the possible contribution of S. spontaneum cytoplasm in the development of new sugarcane cultivars.