|Kang, Manjit - PUNJAB AGRIC UNIV|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 26, 2007
Publication Date: June 6, 2008
Citation: Glaz, B.S., Kang, M.S. 2008. Location Contributions Determined via GGE Biplot Analysis of Multievironment Sugarcane Genotype-Performance Trials. Crop Science. 48:941-950 (2008) Interpretive Summary: Sugarcane in Florida provides about 25% of the sugar produced domestically in the U.S. and is the major agronomic crop of Florida. The cooperative sugarcane breeding program in Florida (supported by USDA-ARS, University of Florida, and the Florida Sugar Cane League, Inc.) has consistently identified productive cultivars for the organic soils that comprise about 80% of the 400,000 acres of sugarcane in Florida, but has not been as successful in identifying productive cultivars for the remaining 20% of the industry on mineral (sand) soils. A concern among cooperators in the program is that having eight locations with organic soils and two locations with sand soils in the final testing stage may not be sufficient to meet the needs of growers with sand soils. This retrospective study reviewed data from 4 years of the final testing stage of the program to determine if the sand location (the most recent complete set of retrospective data had only one sand location) was providing unique information for genotypes and to identify among the eight locations with organic soils, one location that if replaced by a location with sand soil, would be least likely to lessen the ability of the program to identify high yielding cultivars for organic soils. Graphs were developed with commercial software (that analyzes genotype main effects plus genotype x environment interaction)to compare the relative ability of locations to discriminate among genotypes and provide unique information about genotypes. It was found that the location with sand soil generally provided unique information about genotypes, but that due to increased variability at this location, generally did not discriminate well among genotypes. Thus, a concern was raised that as the program progressively replaces organic-soil locations with sand-soil locations, its ability to identify high yielding genotypes may lessen. Among the locations with organic soils, Osceola and Knight Farm were identified as providing similar information on genotype performance and they generally did not discriminate well among genotypes. Thus, it was recommended that one of these locations be replaced with a sand-soil location. It is hoped that this information will provide one key step for the cooperative sugarcane cultivar development program to better meet the needs of all Florida sugarcane growers. It is however emphasized in this report that changes may be necessary throughout the program, not only in its final selection stage, to improve the program’s ability to develop and identify high yielding sugarcane cultivars for sand soils.
Technical Abstract: Selection for productive sugarcane (Saccharum spp.) cultivars in Florida has been more successful for organic than sand soils. The objectives of this study were to assess the contributions of the location with a sand soil to the final stage of multi-environment testing of sugarcane genotypes in Florida, and to identify locations with organic soils that, if replaced with a sand soil location, would be least likely to compromise cultivar selection for organic soils in Florida. Sixteen genotypes per location were harvested in two or three crop cycles from 2002 to 2005 at nine locations. Traits analyzed were cane and sucrose yields (Mg ha-1) and theoretical recoverable sucrose (g kg-1). Variations for genotypes, locations, crops, genotype x location (GL) interaction, and crop x genotype x location (CGL) interaction were highly significant for all three traits, with location usually being the largest contributor to variability in individual crop-cycle analyses. The location with a sand soil, Lykes, was generally not highly representative of locations or highly discriminating of genotypes. These results, in addition to the previously identified need to improve genotype selection on sand soils, suggest that it may be advantageous to add a location with sand soil to this testing program, although doing so may compromise genotype discrimination for theoretical recoverable sucrose (TRS) and sucrose yield. Ability to identify productive cultivars on organic soils by the Florida sugarcane selection program would be least compromised by replacing either Osceola or Knight with a sand-soil location.