Submitted to: Sugar Journal
Publication Type: Abstract Only
Publication Acceptance Date: May 10, 2010
Publication Date: June 18, 2010
Citation: Del Blanco, I.A., Glynn, N.C., Davidson, R.W., Comstock, J.C., Milligan, S., Glaz, B.S., Edme, S.J., Irey, M. Repeatability of Sugarcane Selection on Sand and Organic Soils. Sugar Journal.
The Canal Point (CP) Sugarcane Cultivar Development Program (a cooperative program between the USDA-ARS, the University of Florida and the Florida Sugarcane League) has been more successful at breeding for cultivars adapted to organic soils (muck) than for those adapted to sand soils. Currently, only the last two stages of the selection process are tested on sand soils with a reduced set of genotypes that had previously been selected on muck. This strategy might not be identifying all the best sand-adapted genotypes. To test this hypothesis, an intermediate selection stage (Stage 2), which is regularly planted exclusively on organic soil (Torry muck) at Canal Point, FL was also established and sampled for two years (2007-09) on a sand soil (Margate sand) at Townsite Farm of US Sugar Corporation near Clewiston, FL. The analysis of an identical set of genotypes for both soil types resulted in a genotype x environment interaction significant for all traits and years. Spearman rank correlations among traits for sand and muck were significant but low. Theoretical recoverable sucrose (TRS) had the highest correlation between locations (r=0.31 across years) while tons of cane per acre (TCA) and tons of sucrose per acre (TSA) had the lowest (r=0.23 and r=0.21, across years, respectively). Repeatability (R) between sand and muck was higher for TRS (0.31 across years) and lower for TCA and TSA (0.25 and 0.22 across years, respectively). Results indicated that there were a low number of genotypes with similar performance for both soil types. Therefore, some clones that were not selected in the Stage 2 on muck soil were selected in the Stage 2 on sand and vice versa. This may explain the lower efficiency of the current program in identifying genotypes adapted to sand soils.