Processing of frost- damaged beet remains a significant topical issue for the sugar industry. The growth of microbiological infections in frost-damaged beet leads to several changes in the chemical composition of beet. Microorganisms play a major role in the hydrolysis of sucrose and the production of various metabolites, especially exopolysaccharides. Exopolysaccharides in the raw juice disrupt in normal processing operations, especially purification. The paper shows how exopolysaccharides influence calcium-sludge particles' size distribution, filtration, and sedi- mentation during juice purification. The research was conducted under laboratory conditions using standard dextran and exopolysaccharides extracted from degraded beet of different origins. Findings indicate that the natural exopolysaccharides extracted from the deteriorated sugar beet adversely impacted the purification process more strongly than dextran.
The sugarcane borer Diatraea saccharalis is a major pest of sugarcane (Saccharum spp. hybrids) in the Americas. The insect is partially controlled by cultural, biological, and chemical methods but still causes significant economic losses to sugarcane growers and processors. Currently, one of the most efficient strategies for pest control in other crops is the use of transgenic plants harbouring genes from Bacillus thuringiensis (Bt), which encode crystalline proteins (Cry and/or Vip) with insecticidal activity, known as Bt genes/proteins. In sugarcane, the expression of individual Bt proteins has been previously reported, but not the stacking of two or more Bt proteins. In this study, Bt genes were incorporated by microprojectile bombardment into embryogenic sugarcane calli of the clones TUC 95-10 and TUC 03-12. The presence of the transgenes in 33 transgenic lines was verified by using PCR assays. Subsequently, transgenic lines were acclimated and multiplied in the greenhouse to generate vegetative material for their phenotypic and molecular assessments. The expression levels of transcripts in candidate lines were quantified by real time quantitative PCR (qRT-PCR) assays. In conclusion, transgenic sugarcane lines with a higher level of expression of Bt transcripts compared with the control were developed. These promising lines will be used for future phenotypic tests to determine their resistance against D. saccharalis.
In the South African sugarcane industry, as in many countries, poor adoption of irrigation scheduling is common, leading to ineffective use of irrigation water and loss in yield and income. The reasons for the lack of adoption include economic constraints, difficulty with implementation and human perceptions. To demonstrate the benefits of effective irrigation scheduling under local conditions, a demonstration trial was conducted over 5 years at Pongola, South Africa. Here, a fixed irrigation schedule (control) was compared with three scheduling treatments: (1) the MyCanesim® computer model with data from an automatic weather station; (2) soil-water data from a capacitance probe; and (3) a combination treatment, where MyCanesim® was integrated with a capacitance probe. The number of stress days from either under- or over-irrigation, along with the RV (recoverable value) yield, irrigation applied, irrigation water productivity (IWP) and financial benefits was used to assess each treatment. The adoption of irrigation scheduling was also evaluated through farmer surveys before and after the trial. When compared to the fixed-cycle control, the use of irrigation-scheduling techniques resulted in an increase of up to 13% in RV yield, a reduction of up to 58% in irrigation water applied, improved IWP of up to 23.9 t cane/100 mm of irrigation and financial benefits of up to ZAR10,487/(ha · a) (USD698/(ha · a)). The combination treatment incurred the least water-stress days, 79% lower than the control. Farmer surveys showed an increase of 45% in the adoption of irrigation scheduling, from 11% (n = 111) in 2014 to 56% (n = 100) in 2020. Although site-specific, the trial results show substantial benefits that can be realised by scheduling irrigation. The trial results compare well to other similar studies, showing that the results can be used in other areas to promote the adoption of irrigation scheduling.
Digital cameras are widely used tools for plant monitoring in plant science today. Used to track plant growth or even visible symptoms, they are important tools for breeding and plant protection field trials. Nevertheless, its extension to measure the near infrared (NIR) region (700–1000 nm) includes great potential as plants show a higher light reflectance within this spectrum. Various applications have shown its use for disease detection, quantification, virus content estimation, and stress monitoring. As the next step is a comprehensive integration into agricultural routines, this study will show two use-cases with a high technological readiness level. One use-case shows a handheld multispectral sensor, which is used for manual measurements to detect and discriminate different virus types in sugar beet. In contrast, the second use-case shows a transfer to an UAV based disease quantification routine based on spectral imaging for Cercospora leaf spot. In addition, two prototypical workflows are shown for processing non-imaging and imaging spectral data in an agricultural setting. This study shows the state of the art in spectral sensing in the field for the two major sugar beet diseases – virus yellows and Cercospora leaf spot. Furthermore a future perspective for coming technological challenges regarding the integration of AI in sensors or robotic workflows is provided.
Ratoon stunting disease (RSD) is caused by the bacterium Leifsonia xyli subsp. xyli. The disease causes significant yield losses in sugarcane crops (Saccharum hybrids) throughout the world. Three diagnostic techniques for detecting RSD in fields in the Herbert sugarcane region were assessed in 2022: qPCR on leaf sheath biopsy samples (LSB-qPCR); qPCR on expressed xylem sap; and phase-contrast microscopy (PCM) on expressed xylem sap. The LSB-qPCR leaf sheath biopsy is taken from the lowest green leaf sheath of the plant. Differences among techniques were compared for confirmation of the presence or lack of RSD detected, the time required to collect and process samples, the fee to undertake the sampling, safety considerations and transport costs. Differences were identified among the three sampling methods concerning RSD detection, costs associated with sample collection, processing, and some safety related issues. LSB-qPCR was the most efficient and cost-effective diagnostic platform for RSD.
