Browsing by Author "Croft, B"

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Development of DNA based diagnostic systems for sugarcane pathogens : SRDC final report UQ024
(BSES, 2001) Maclean, D; Henderson, J; Croft, B
This project developed diagnostic assays for sugarcane pathogens using novel DNA detection technologies associated with the polymerase chain reaction (PCR). The bacterium Clavibacter xyli subsp. xyli (Cxx) causing ratoon stunting disease (RSD) was used as major model to compare assay platforms based on PCR-ELISA (Boehringer) and TaqManTM real time PCR (Applied Biosystems). TaqMan was more sensitive, robust, and subject to less interference than PCR-ELISA. Laboratory tests and field trials using cultured Cxx cells and xylem fluids from RSD-infected cane demonstrated that TaqMan could detect fewer than 10 bacterial cells reliably, and was >100x as sensitive as previous ELISA and phase contrast microscopy methods. Quantitative TaqMan assays appeared to be congruent with these existing methods. TaqMan assays were also developed for Fiji disease fijivirus (FDV) and sugarcane mosaic potyvirus (SCMV). BSES can readily access this advanced technology via the Real Time PCR Facility at the University of Queensland. Compared to alternative methods the TaqMan assays are inherently time-efficient, robust, highly sensitive, quantitative, and are especially well suited for rigorous quality control. These tests are recommended for ongoing evaluation for quarantine and other purposes by the Australian sugar industry. TaqMan is a robust generic technology and assays can readily be developed for further pathogens if the need arises.
Optimising productivity and variety recommendations through analysis of mill data : ASSCT peer reviewed paper
(ASSCT, 2016) Stringer, JK; Croft, B; Di Bella, L; Sefton, M; Nielsen, R; Larsen, P; De Lai, R; Davies, I
Production peaked in the Herbert River mills in 2005 but since then productivity has declined. Analysis of mill data in the Herbert has successfully identified groups of farms with similar productivity over time and the major factors associated with these groupings. The major finding of the study was that those growers who have adopted new farming systems had significantly higher productivity than those who use traditional practices. The impact of the Pachymetra resistance of previous varieties on yield of the current crop was also significant, suggesting this may be a major factor contributing to poor ratooning in the Herbert. In the small farm size groups, low and high performing growers had similar levels of % plant, % young crops, % old crops and % old varieties. However, the low and high performing groups varied significantly in terms of new varieties, suggesting that the small farm size low performing group were not adopting the new, more productive varieties to the same extent as the small farm size high performing group. Manager’s age was also an important factor associated with cane yields. Growers who regularly (five or six years out of six) obtained clean seed had more than 10% higher yields than growers who never or infrequently obtained clean seed and greater than 6% higher yields than growers who only obtained clean seed in three or four years out of six. Results from this research has allowed the Herbert Cane Productivity Services Limited (HCPSL) to design targeted extension strategies with the region. This will result in better variety recommendations and increase productivity.
Rapid detection of ratoon stunting disease; final report 2013/001
(Sugar Research Australia Limited, 2016) Berna, A; Trowell, S; Croft, B
This project's objective was to develop a rapid 'sniff test' to diagnose ratoon stunting disease (RSD) using a new technology called 'Enose' or electronic nose. The aim was to be able to identify contaminated cane within minutes in the field, rather than wait for samples to be aggregated, shipped to, and tested at a central laboratory and with a procedure that takes more than a day to complete. Some species of pathogenic bacteria can be characterized by the volatile chemicals they produce and it is believed that Leifsonia xyli will be the same. The proposed test could be applied to a large number of sap samples or to freshly cut cane in a sampling chamber. The headspace would be drawn off the sample and analysed by Enose with minimal processing. The test could be automated and performed in a laboratory or, if desired, close to or in the field. The eNose test would improve RSD management and reduce costs to Productivity Service companies.