Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2010
Publication Date: 7/6/2010
Citation: Lingle, S.E., Johnson, R.M., Tew, T.L., Viator, R.P. 2010. Changes in Juice Quality and Sugarcane Yield with Recurrent Selection for Sucrose. Field Crops Research. 118:152-157.
Interpretive Summary: Sugarcane breeding programs in Louisiana have made improving sucrose content a top priority. Comparisons of new with old varieties allow breeders to determine how well the breeding program is doing. In this study, we grew five varieties from each of seven generations of sugarcane from the Louisiana breeding programs. Cane yield and juice quality were determined. Varieties from the last three generations were superior to varieties from the first three generations for juice Brix (total soluble solids), sucrose and purity (Brix/sucrose), sucrose content of the cane, cane yield per acre and sugar yield per acre. Fiber, which was selected to be between 11 and 14% cane in all generations, was not different among the generations. Total soluble solids (Brix) in the cane increased at a rate of about 0.3% per generation. Sucrose in the cane increased by 0.4% per generation. Juice purity (Brix/Sucrose) increased by about 0.9% per generation, and sucrose content increased by 7 pounds/ton cane per generation. Sucrose yield has been increased by 1.7 t/acre per generation. Juice quality and sucrose yield did not increase in the last three generations. This may indicate that improvement has slowed, and different sources of new sucrose genes should be included in the breeding program.
Technical Abstract: Sugarcane (Saccharum spp. hybrids) breeding programs in Louisiana have made improving sucrose content a top priority. The cultivars with the highest sucrose content are crossed, and a new generation of cultivars is selected from the progeny. This study was designed to test the hypothesis that six cycles of recurrent selection for sucrose in Louisiana has increased sucrose content and sucrose yield in sugarcane. Five cultivars from each of seven generations of recurrent selection in Louisiana were planted in 2004 and 2006. The plant and first stubble crops were harvested late in the harvest season from each planting. Cane yield and juice quality were determined. Cultivars from the last three generations were superior to cultivars from the first three generations for juice Brix, sucrose and purity, TRS, cane yield and sugar yield. Fiber, which was selected to be between 11 and 14% cane in all generations, was not different among the generations. Six cycles of recurrent selection for sucrose have increased Brix % cane by almost 2%, sucrose % cane by more than 2%, and theoretically recoverable sugar (TRS) by 20 kg Mg-1 cane. Sucrose yield has been increased by about 4 Mg ha-1. A plateau in juice quality and sucrose yield in the last three generations may indicate that the genetic potential for late season juice quality has been reached, although significant linear regressions point to continuing improvement. Since S. officinarum is the source of most of the high sugar genes, integrating new S. officinarum germplasm in the breeding program may bring in new high sucrose genes.