Browsing by Author "Rae, A"

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Faster flowering - new opportunities for genetic improvement: final report 2012/024
(Sugar Research Australia Limited, 2015) Rae, A
In sugarcane, flowering is essential to breeding but is not a pre-requisite for commercial production. Consequently, our knowledge of the processes that control flowering lags behind other crops where the seed is the commercial product. Recently, sugarcane breeders have successfully used photoperiod treatments to harmonise flowering times in parents for crossing, however genetic improvement is still hampered by the inconsistent flowering of clones and by the long cycling time. Important gains could result from technology to induce flowering 'on demand' without the current environmental and infrastructure constraints. The ability to induce flowering in younger plants would significantly reduce the generation-to-generation cycle time and therefore speed up: (i) recurrent selection and introgression breeding; (ii) transfer of GM events from a single cultivar into a range of backgrounds; and (iii) production of inbred lines for genetic studies. These tools would speed up variety improvement and allow the development of new genetic resources. The aim of this project was to develop knowledge and test methods to induce flowering more frequently.
Sugarcane compositional analysis to enable food safety assessment of modified varieties
(2013) Rae, A; Bonnett, G
An important component of demonstrating that the products of GM sugarcane varieties are substantially equivalent to conventional varieties is whether the nutritional composition falls within the range of compositions that are currently found in production. For sugarcane, the food safety assessment will focus on the stalk, as the plant part that provides the food product, and the nutritional components that will be assessed are the proximates (comprising moisture content, crude fibre, protein, fat, ash and N-free extractives) and the soluble sugars. For feed purposes, information on the proportions of neutral detergent fibre (NDF) and acid detergent fibre (ADF) will also be required. Although some components such as sugars are routinely measured in sugarcane stalks, there was a lack of information on most of the nutritional components. The aim of this project was to determine the range of nutritional compositions found in Australian sugarcane varieties under normal agronomic practices
Sugarcane root systems for increased productivity; development and application of a root health assay : final report 2015/002
(Sugar Research Australia Limited, 2018) Rae, A; Pierre, J
A better understanding of the sugarcane root system has the potential to improve productivity and overcome soil constraints. By adapting the digital methods that have been developed in other crops, we have developed a toolkit of reliable methods that enable analysis of large numbers of root samples. These methods have been used to provide a baseline understanding of the range and variation of root parameters for sugarcane, including root/shoot ratios, root opening angle, root length, proportion of fine roots, branching density, average diameter and diameter in each size class. We found a consistently high proportion of fine roots, but there was genetic variation for many other key traits amongst current commercial lines. Importantly, there were no significant reductions in root system size or quality in modern varieties compared to older varieties. The methods and baseline were then applied to test the response to stresses encountered in Australian growing environments. When comparing plants with or without YCS symptoms, we found no differences in root system structure, despite significant reductions in shoot mass. Limiting growth by removal of tillers or by restricting nitrogen availability identified plasticity in specific root traits that enabled the plants to adapt to the restrictions. Root system distribution by depth, and relative allocation of resources to the root system showed adaptations to stress while root angle appeared to be stable. With the new methods and knowledge of trait plasticity, we can now start to test which traits provide a benefit in various agronomic situations and develop an integrated understanding of root health which can be used to monitor soil health and promote the adoption of better agronomic practices.