Impact of stool architecture on ratooning ability : final report 2015/004

Abstract

Crop productivity is very much dependent on ratoon performance with at least 75% of the crop consisting of ratoons of varying age. There are efforts to improve crop management techniques to maintain ratoon yields, but there are significant gaps in our knowledge of traits that contribute to ratoonability and which could provide the basis for selection of improved varieties. The aim of this project was to investigate stool architecture traits that may contribute to ratoon performance in the context of a highly mechanised industry. Under the guidance of an industry consultative panel, we developed methods to compare genotypes, including measures of the number and position of sprouted buds in the stool. These methods were applied to analysis of pot-grown plants (with optimisation of pot size), commercial field samples, a range of Saccharum progenitor species, and a field trial of 32 genotypes encompassing a 50-year timeline of released varieties. The results showed significant genotype differences in all measured traits including bud position. Trait changes were observed in the 1st ratoon compared to the plant crop, but importantly, there was no indication that modern varieties are significantly different from older varieties. Industry yield data was tested for correlations with the trait measurements. Continuation of the field trial will provide valuable insights into changes in stool structure that can be used to understand ratoon performance.