THE IMPACT OF GENOTYPE X ENVIRONMENT INTERACTIONS FOR SUGAR YIELD ON THE USE OF INDIRECT SELECTION IN SOUTHERN QUEENSLAND

To develop a strategy to improve the efficiency of selection, indirect selection and pattern analysis were used to examine the magnitude and form of genotype x environment (GE) interactions for sugar yield in sugarcane clones in southern Queensland. Clone x location interactions were the predominant source of clone x environment interactions and were much larger than clone x crop-year and clone x location X crop-year interactions. Both the indirect selection study and the pattern analysis emphasised the relative magnitude of these sources of interactions. Pattern analysis strongly associated crop classes at each location, and indirect selection analysis emphasised an opportunity to exploit correlated genetic advance between crop classes within a location. These suggest that more emphasis should be placed on sampling a greater number of locations than on the testing of clonal ratooning ability within locations. This would improve the chances of obtaining both broadly and specifically adapted sugarcane varieties.