Submitted to: Agronomy Society of America, Crop Science Society of America, Soil Science Society of America Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 12, 2006
Publication Date: November 12, 2006
Citation: Lingle, S.E., Tew, T.L., Viator, R.P., Johnson, R.M. 2006. How much has recurrent selection increased sucrose yield in sugarcane? [abstract]. Available: http://crops.confex.com/crops/2006am/techprogram/P23659.htm Technical Abstract: Commercial sugarcane cultivars are complex, polyploid, interspecific hybrids, primarily of S. officinarum and S. spontaneum. Most breeding programs need about twelve years to develop a new cultivar. Since the 1920's, Louisiana sugarcane breeding programs have used recurrent selection to improve sucrose yield, a product of cane yield and juice sucrose content. In this study, we compared some juice quality and yield components in five cultivars from each of seven cycles of recurrent selection for sucrose, in order to determine the effectiveness of the program in increasing sucrose yield. The 35 cultivars were planted in November 2004 and harvested by chopper harvester on 6 December 2005. A random sample of stalk pieces was collected from each plot as the cane was harvested. Tissue preparation and juice analyses (Brix, Pol, and purity, expressed as % of cane) were done by industry-standard procedures. Cane yield ranged from 58 t/ha in the second cycle to 88 t/ha in the fifth cycle, while theoretically recoverable sugar ranged from 93 kg/t in the second cycle to 113 kg/t in the seventh cycle. Recurrent selection increased sucrose yield from 6.2 t/ha in the first cycle to 9.5 t/ha in the seventh cycle. A rapid increase in yield and juice quality through the fourth cycle of recurrent selection appears to have slowed in the last three cycles. For instance, sucrose % cane increased an average of 4% per cycle in the first four recurrent selection cycles, and 1% per cycle in the last three cycles. We hope to identify the cause of this plateau by measuring changes in parameters of growth and sugar accumulation that resulted from recurrent selection. Identifying which components are no longer being improved by selection may allow us to seek new germplasm with new sources of variability in those components.