Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract Only
Publication Acceptance Date: 4/3/2018
Publication Date: 9/1/2018
Citation: Pan, Y., Burner, D.M., Todd, J.R. 2018. New sugarcane hybrids in Saccharum spontaneum cytoplasm developed through a combination of conventional and molecular breeding approaches [abstract]. Journal of the American Society of Sugar Cane Technologists. 38:56.
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, ratoon ability, and disease and insect resistance. There was no report on S. spontaneum being used as female parents before 1997, 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 in order to make interspecific crosses. The 1997 cross was made between a S. spontaneum clone Djatiroto from Indonesia and the Louisiana sugarcane 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. From the 1997 cross, five F1 progenies were selected based on phenotypic traits and RAPD DNA marker analysis. Their authenticity was further confirmed by SSR DNA fingerprints. One progeny (US 99-43) that produced the largest stalks with the highest Brix values was chosen for further improvement through cycles of backcrossing, field evaluation, and selection. Five BC2 progenies were selected in 2008. One of them, Ho 08-9504, produced eight large stalks with a Brix value of 23.8. It never flowered in Louisiana, but flowers readily in Florida. In 2014, its flower was hot-water emasculated prior to crossing to HoCP 04-852 at Canal Point, FL. Two hundred and sixteen BC3 progenies were planted at the USDA-ARS Ardoyne Farm in Schriever, LA in 2015, of which 36 were advanced to 1st line trials in 2016. Seven BC3 progenies were selected and advanced to 2nd line trials in 2017. Each BC3 progeny produced 11 to 20 stalks with an average diameter of 25-32 mm and Brix value of 19.6-22.4 and were free of diseases and borers. Pedigree analysis indicated that these seven BC3 progenies may also inherit some nuclear genes from S. spontaneum, S. robustum, and Erianthus. Availability of these S. spontaneum cytoplasm-containing BC3 progenies may enhance the 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.