EFFECT OF DRYING CONDITIONS ON TRITICALE SEED GERMINATION AND RICE WEEVIL INFESTATION
The combination of high protein content and a soft seed coat makes the wheat-rye hybrid Triticale (Triticosecale) vulnerable to attack by rice weevils. Drying triticale grain to moisture contents safe for storage can prevent infestation by rice weevils, but if grain is being stored for seed, high drying temperatures can affect seed germination. Grain can be effectively dried at low temperatures, but low-temperature drying is difficult in hot, humid regions such as the Gulf Coast. This study investigated the effects of drying temperatures from 35°C to 45°C on triticale seed germination and found no statistical differences between the germination rates of the seed at any of the drying temperatures and the germination rates of controls. Final moisture contents after drying ranged from 7.9% wet basis (w.b.) at 45°C for 48 h to 9.7% w.b. at 35°C for 24 h. New generations of rice weevils appeared in the control samples maintained at 23°C and 13.8% or 13.9% w.b. but were not observed in grain dried at any of the drying treatments. The results of this study showed that triticale seed can be dried to moisture contents that effectively control rice weevil infestation in hot, humid climates without significantly affecting germination rate.
Research on procedural optimization and development of agricultural drying processes
Abstract Drying is the most important post-harvest process for fast and safe preservation of agricultural products, but it is also energy-intensive at the same time. Agricultural drying is particularly energy-demanding for several reasons – high differences between harvest and storage moisture content, low drying temperatures, and low levels of pre-treatment due to sensitivity to thermal and mechanical stress. Well-established methods for increasing heat and mass transfer, such as surface enlargement and agitation of the bed material, are not applicable for many products. Therefore, farmers depend on optimum harvest windows and weather conditions as well as powerful drying systems in order to attain high product quality, to avoid deterioration, and to process large amounts of produce at the same time. Consequently agricultural process engineers have to compromise between gentle drying, energy efficiency and high drying capacity in order to approach optimum process quality for a specific crop. The current research activities of the Drying Group at ATB Potsdam addressing agricultural drying of grain are presented in this paper.
Original paper: Diagnosis of bacterial spot of tomato using spectral signatures
Ultraviolet, visible, and near-infrared reflectance spectroscopy was used to determine the disease severity of tomato (Lycopersicon esculentum) leaves infected with Xanthomonas perforans, the causal agent of bacterial leaf spot of tomato. Chemometric methods were used to identify significant wavelengths and create spectral-based prediction models. Significant wavelengths were identified through analysis of the B-matrix from partial least squares (PLS) regression, analysis of a correlation coefficient spectrum, and through the use of a stepwise multiple linear regression (SMLR) procedure. These analysis methods revealed several significant regions wavelengths and produced predictive models of disease severity based on absorbance spectra. The best model predicted the disease severity of the validation data set with a root mean square difference (RMSD) of 4.9% and a coefficient of determination (R^2) of 0.82. The results of this initial study indicate the potential for the use of spectral technology to detect bacterial leaf spot of tomato in the field.