Completed projects and reports

Now showing 1 - 4 of 4

Development and application of spatial analysis to improve precision in selection trials : SRDC final report BSS231
(2004) Stringer, JK
In the early stages of selection, a sugarcane breeder tests a large number of genotypes. As the amount of planting material for each genotype for testing is typically limited, selections are usually made on small, unreplicated, single-row plots. Unfortunately, such designs are prone to errors arising from spatial variability and interplot competition, which, unless accounted for, can seriously bias variety estimates and reduce genetic progress.In this project, an approach to the simultaneous modelling of spatial variability and interplot competition is developed. This approach combines nearest-neighbour techniques to model spatial variability, together with the genotypic and phenotypic interference models to estimate interplot competition. The joint modelling and standard approaches are compared using 23 sugarcane data sets for cane yield. Agreement between the two approaches varied from approximately 38% to 90%. Hence, for some trials there would be large differences in the selections to be advanced to final assessment trials. Additionally, for two trials, the joint modelling approach was applied to cane yield and CCS data. The number of selections in common for sugar yield for the two approaches was compared. Approximately 43% and 75% of the clones were in common, indicating that appropriate modelling of interplot competition and spatial variability can have a very large effect on the varieties to be advanced to final assessment trials.This project has resulted in an improved selection system, and this is likely to result in increased genetic gain through the advancement of superior varieties to later stages.The project has formed the basis of a PhD thesis submitted to the University of Queensland.
Field performance of transgenic sugarcane plants carrying genes for resistance to SCMV : final report BSS154
(2000) Smith, GR; Taylor, GO; Harding, RM; Stringer, JK; Cox, MC; Yoyce, PA
The field resistance of transgenic sugarcane plants to sugarcane mosaic potyvirus was successfully demonstrated, and a number of transgenic lines are available for consideration for agronomic evaluation. Some of the transgenic lines yielded significantly more tonnes sugar per hectare in this trial, but a firm conclusion about the overall performance of the transgenic lines compared to the parental clone can not be concluded due to the limitations of this trial. These plants contain the coat protein gene of sugarcane mosaic virus and prove that pathogen-derived resistance can be engineered into a genetically complex monocot. The precise molecular basis of the resistance appears to be RNA mediated. More research is necessary to prove this as a number of the resistant lines do not exhibit the usual RNA profiles of transgenic plants from other species which are virus resistant. A second pathogen-derived resistance gene, based on the virus replicase gene, is also capable of conferring virus resistance in sugarcane.Analysis of sugar and syrup produced from transgenic cane has revealed that no genes, native or transgenic, survive the laboratory production process. There is every confidence that this result would also be found with mill produced sugar, when the opportunity to mill transgenic sugarcane eventuates. There is now good scientific evidence to contribute to the debate that sugar manufactured from transgenic sugarcane plants is indistinguishable or substantially equivalent to sugar produced from non-transgenic plants.
Best linear unbiased prediction as a method for predicting cross potential : SRDC final report BS119S
(1999) Stringer, JK
Until recently, BSES breeders used an empirical formula to assess the breeding potential of a parent (Hogarth and Skinner, 1986). Although this method uses data from many sources, it needs to draw on data accumulated for up to ten years to provide reliable estimates. An alternative is the statistical technique called Best Linear Unbiased Prediction (BLUP) which was developed to predict breeding values from dairy cattle data sets which are typically highly unbalanced and from diverse sources.The main objective of this study was to compare the relative efficiencies of BLUP and the existing empirical method for identifying superior sugarcane cross combinations. There was little difference in the agronomic performance of crosses selected using either BLUP or the empirical method but BLUP proved to be the quicker method and should allow more rapid progress from breeding and selection.
Evaluation of methods of estimating breeding value of sugarcane parental clones : SRDC final report BS75S
(1996) Stringer, JK
BSES uses an empirically based index to assess the breeding potential of sugarcane (Saccharum spp.) parents and this may take many years to provide reliable estimates. A rapid and efficient method of assessing the breeding value of parents in early stage families is needed to increase the rate of population improvement.

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