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Beta Regression Model for Predicting the Development of Pink Rot in Potato Tubers During Storage Full text
2016
Yellareddygari, S. KR. | Pasche, Julie S. | Taylor, Raymond J. | Hua, Su | Gudmestad, Neil C.
Pink rot is an important disease of potato with worldwide distribution. Severe yield and quality losses have been reported at harvest and in postharvest storage. Under conditions favoring disease development, pink rot severity can continue to increase from the field to storage and from storage to transit, causing further losses. Prediction of pink rot disease development in storage has great potential for growers to intervene at an earlier stage of disease development to minimize economic losses. Pink rot disease is estimated as percent rot confined on the interval (0 or 1, corresponding to 0% as no disease and 100% as maximum disease). In this study, beta regression is considered over the traditional ordinary least squares regression (linear regression) for fitting continuous response variables bounded on the unit interval (0,1). This method is considered a good alternative to data transformation and analysis by linear regression. The percentages of incidence of pink rot in tubers at harvest, yield, and days after harvest were used as study covariates to predict pink rot development from 32 to 78 days postharvest. Results demonstrate that the interaction between percentage of pink rot at harvest and yield is a significant predictor (P < 0.0001) of the beta regression model. A linear regression model was also designed to compare the results with the proposed beta regression model. Linear predictors observed in diagnostic plots with linear regression model was found to not be constant and an adjusted R² (0.49) was obtained. The pseudo R² (0.56) and constant variance for this study suggests that the beta regression function is adequate for predicting the development of pink rot during storage. The use of the beta prediction model could help growers decide whether to apply a fungicide to tubers going into storage or to market their crop before significant storage losses are incurred.
Show more [+] Less [-]Respiration rate, physico-chemical fruit quality and consumer acceptability for Fajri mango under different storage temperatures
2016
Raza, S.A. (University of Agriculture, Faisalabad (Pakistan). Inst. of Horticultural Sciences) | Khan, A.S. (University of Agriculture, Faisalabad (Pakistan). Inst. of Horticultural Sciences) | Malik, A.U. (University of Agriculture, Faisalabad (Pakistan). Inst. of Horticultural Sciences) | Amin, M. | Asad, H.U. | Razzaq, K.
Fajri is a commercial yet scientifically an unexplored mango cv. of Pakistan. Due to large fruit size and being mid to late season in fruit maturity, it has tremendous potential for export. The storage life and quality of mango cv. 'Fajri' at low temperature has not been standardized. Present study was aimed to investigate the effect of low temperature storage on fruit quality and shelf-life of mango cv. 'Fajri'. Fruits were harvested at commercial maturity and stored at 10, 12 or 14 plus minus 1 degree C with 80-85% RH for 21 days. After storage, the rate of respiration in the fruit stored at 12 and 14 degree C remained 1-2 times higher than fruit kept at 10 degree C. Storage of fruit at 14 degree C resulted in significantly higher fruit skin shriveling, fruit softening and disease incidence severity as compared to at 10 and 12 degree C. The fruit stored at 10 and 12 degree C showed statistically similar behaviour regarding fruit peel colour, fruit softness, disease incidence, disease severity, skin shriveling, acidity, SSC: TA ratio, total and reducing sugars contents. However, no chilling injury of fruit was observed at any storage temperatures. The extent of yellow peel colour and disease incidence was significantly higher at 14 degree C compared to fruit stored at 10 and 12 degree C. In conclusion, the fruit of cv. 'Fajri' exhibited extended (21 days) storage life with better fruit quality at 10 and 12 degree C compared to 4-5 days of under ambient conditions (32 plus minus 1 degree C; 55-60% RH). Study emphasized the need to further investigate and develop the strategies for disease management and post-storage peel colour development for better consumer acceptability.
Show more [+] Less [-]Production locality influences postharvest disease development and quality in mangoes Full text
2016
Fiaz, M. | Malik, A. U. | Amin, M. | Khan, A. S. | Rehman, A. | Alam, M. W. | Hofman, P. J. | Johnson, P.
Production locality influences postharvest disease development and quality in mangoes Full text
2016
Fiaz, M. | Malik, A. U. | Amin, M. | Khan, A. S. | Rehman, A. | Alam, M. W. | Hofman, P. J. | Johnson, P.
Postharvest disease management is one of the key challenges in commercial mango supply chains. Comprehensive investigations were made regarding the impact of geographic locality on postharvest disease development and other quality parameters in ‘Sindhri’ and ‘Samar Bahisht (S.B.) Chaunsa’ mangoes under ambient (33±1°C; 55-60% RH) and low temperature storage/simulated shipping (12±1°C; 80-85% RH) conditions (28 or 35 days storage for ‘Sindhri’ and 21 or 28 days for ‘S.B. Chaunsa’). Physiologically mature (days from fruit set were 95-100 and 110-115 for ‘Sindhri’ and ‘S.B Chaunsa’, respectively) ‘Sindhri’ and ‘S.B. Chaunsa’ fruits were harvested from five geographic localities and subjected to ambient and simulated shipping conditions. Under ambient conditions, no disease incidence was observed till fruit eating stage in ‘Sindhri’. However, in ‘S.B. Chaunsa’, significant variation in different localities was observed with respect to disease incidence. Maximum and at par disease was exhibited by the fruit collected from district Vehari and Khanewal in ‘S.B. Chaunsa’. Under simulated shipping conditions, disease development varied significantly with respect to different locations and storage durations. In ‘Sindhri’, fruit of M. Garh, while, ‘S.B. Chaunsa’ fruit of districts R.Y. Khan, M. Garh and Khanewal showed higher disease incidence. Fruit peel colour development was significantly reduced as storage days increased. Fruit firmness, skin shriveling, fresh weight loss, dry matter, biochemical and organoleptic attributes also varied significantly among the fruit sourced from different orchards of different localities. Analysis of N contents in leaves and fruit peel revealed that N contents of leaf and peel were positively correlated with disease severity in mango. Botryodiplodia spp., Phomopsis mangiferae, Alternaria alternata, Colletotrichum gloeosporioides were the pathogens isolated from fruits of all locations; however, the prevalence frequency varied with the geographic localities. In conclusion, the production locality, cultivar and nutrition (nitrogen content of fruit peel) had significant effect on fruit quality out-turn at ripe stage in terms of disease development so area specific disease management system needs to be implemented for better quality at retail.
Show more [+] Less [-]Production locality influences postharvest disease development and quality in mangoes
Tissue culture studies on a suspected lysosomal storage disease in Abyssinian cats Full text
2016 | 1980
Lange, A. Lucia | Bigalke, R.D. | Cameron, Colin McKenzie | Gilchrist, Frances M.C. | Morren, A.J. | Verster, Anna J.M. | Verwoerd, Daniel Wynand | Walker, Jane B. | Steyn, P.J.J.
The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format. | Cell cultures prepared from the spleen and mesenteric lymph nodes of affected kittens were subjected to histochemical and ultrastructural studies. Macrophages in the cultures contained lipid in the cytoplasm and the ultrastructural studies revealed lysosomes containing lamellae similar in appearance to phospholipids.
Show more [+] Less [-]Effect of Modified Atmosphere Packaging on Postharvest Quality of Mango cvs. Sindhri and Sufaid Chaunsa During Storage Full text
2016
Omer Hafeez | Aman Ullah Malik | Muhammad Shafique Khalid | Muhammad Amin | Samina Khalid | Muhammad Umar
Modified atmosphere packaging (MAP) technology is gaining popularity worldwide for its potential of extending shelf life of fresh produce with better fruit quality. Effect of MAP (using Xtend® bags), was investigated on postharvest storage life and quality of mango cvs Sindhri and Sufaid Chaunsa stored at 11°C with 80-85% RH for 4 and 5 weeks respectively, in comparison with un-bagged (control) fruit. Uniform physiological mature fruit of Sindhri and Sufaid Chaunsa were harvested from a commercial mango orchard along with 4-5 cm long pedicel and were de-sapped in 0.5% lime solution (to avoid sap burn injury). Later on fruit were given cold water fungicidal dip (Sportak @ 0.5ml/L, Active Ingredient: Prochloraz) followed by hot water treatment (52°C; 5 min). After shade drying and pre-cooling (11°C; 10-12 hours), fruit were packed according to the treatment combination and stored at 11°C. Fruit of both varieties were removed after 2, 3 and 4 weeks of storage followed by ripening at 24±2°C with an additional removal after 5 weeks for Sufaid Chaunsa only. Fruit quality was evaluated for various bio-chemical, organoleptic and physical parameters at two stages of ripening (at removal day and at final ripening day). Fruit of both varieties stored in MAP exhibited better firmness and retained green colour as compared to un-bagged fruit. Quality of fruit subjected to postharvest fungicidal application and hot water treatments and stored under MAP at 11°C showed better peel colour development and less disease development. Moreover, storage durations and post storage ripening stages significantly affected fruit peel colour, textural softness and disease development. Further, cv. Sindhri showed better storage potential with lower disease incidence as compared to cv. Sufaid Chaunsa which warrants further studies on disease control aspects.
Show more [+] Less [-]Pre-harvest application of oxalic acid increases quality and resistance to Penicillium expansum in kiwifruit during postharvest storage Full text
2016
Zhu, Yuyan | Yu, Jie | Brecht, Jeffrey K. | Jiang, Tianjia | Zheng, Xiaolin
Kiwifruit (Actinidia deliciosa cv. Bruno) fruits were sprayed with 5mM oxalic acid (OA) at 130, 137, and 144days after full blossom, and then harvested at commercial maturity [soluble solid content (SSC) around 10.0%] and stored at room temperature (20±1°C). Pre-harvest application of OA led to fruit with higher ascorbic acid content at harvest, slowed the decreases in fruit firmness and ascorbic acid content and increase in SSC during storage, and also decreased the natural disease incidence, lesion diameter, and patulin accumulation in fruit inoculated with Penicillium expansum, indicating that the OA treatment increased quality and induced disease resistance in kiwifruit. It was suggested that the increase in activities of defense-related enzymes and in levels of substances related to disease resistance might collectively contribute to resistance in kiwifruit against fungi such as P. expansum in storage.
Show more [+] Less [-]Consistent viral DNA quantification after prolonged storage at ambient temperature Full text
2016
Zaniello, Benjamin | Huang, Meei-Li | Cheng, Anqi | Selke, Stacy | Wald, Anna | Jerome, Keith R. | Magaret, Amalia S.
Long-term storage of biological specimens at low temperatures is costly and impractical in resource limited settings, where the disease burden of chronic viral infections is highest, and the need for research greatest. We examined the necessity of cold storage by comparing the quantity of HHV-8 DNA recovered from swab samples before and after 9–11 months of storage at temperatures of −20°C, 4°C and 37°C. Quantitative levels of HHV-8 DNA remained consistent for laboratory or mucosal swab samples regardless of storage temperature. Freezer storage is determined to be not necessary for mucosal samples destined for HHV-8 DNA quantification.
Show more [+] Less [-]Potential of carboxymethyl cellulose and γ-irradiation to maintain quality and control disease of peach fruit Full text
2016
Hussain, Peerzada R. | Suradkar, Prashant P. | Wani, Ali M. | Dar, Mohd A.
Carboxymethyl cellulose (CMC) coatings alone and in combination with gamma irradiation were tested for maintaining the storage quality and control of post-harvest gray and black mold disease of peach. Matured green peaches were CMC coated at levels 0.5–1.0% (w/v) and gamma irradiated at 1.2kGy. The treated fruit including control was stored under ambient (temperature 25±2°C, RH 70%) and refrigerated (temperature 3±1°C, RH 80%) conditions. In fruits treated with individual treatments of 1.0% (w/v) CMC; 1.2kGy irradiation and combination of 1.0% (w/v) CMC and 1.2kGy irradiation, no decay was recorded up to 6, 8 and 14 days of ambient storage. Irradiation alone at 1.2kGy prevented the onset of disease incidence up to 4 days compared to 2 days by 1.0% (w/v) CMC coating following 30 days of refrigeration. Combination of CMC at 1.0% (w/v) and 1.2kGy irradiation prevented disease incidence of peach up to 7 days during post-refrigerated storage at 25±2°C, RH 70% following 30 days of refrigeration. Above combinatory treatment can be of great potential in facilitating the marketing of the fruit, thereby benefiting the growers.
Show more [+] Less [-]Application of gaseous chlorine dioxide for control of fungal fruit rot disease of harvested ‘Daw’ longan Full text
2016
Longan (Dimocarpus longan Lour.) fruit decay caused by microbial infection during storage is the main problem that results in a great loss of its market value. The objective of this study was to investigate the application of gaseous chlorine dioxide (ClO2) to control fruit rot disease caused by three fungi: Cladosporium sp., Fusarium sp., and Lasiodiplodia sp. in longan fruit. The effect of ClO2 fumigation at 10mgL-1 for 10min on the onset of disease and the activities of two defense enzymes, chitinase and glucanase, in the harvested longan fruits during storage at 25±3°C for 7days were investigated. The inhibition of fungal growth and spore germination, and oxidative damage to fungal membrane by gaseous ClO2 were also studied. It was found that ClO2 fumigation could significantly reduce disease incidence (by 20–75%) and disease index (by 28–38%) of the inoculated longans and markedly increased chitinase and glucanase activities during 7days of storage. ClO2 stimulated the activity of chitinase and glucanase which were increased by 29.45–58.89% and 68.98–78.12%, respectively higher than those in the inoculated controls. ClO2 was more efficient in stimulating the activity of glucanase than that of chitinase. ClO2 also increased fungal membrane damage by causing an increase in malondialdehyde and conjugated diene contents, lipoxygenase activity and electrolyte leakage. The increase in the activities of both enzymes in fruits and the increase in fungal membrane damage causes by ClO2, were in accordance with the inhibition of fungal growth and spore germination, leading to the reduction of fruit rot disease suggesting that it is the response mechanism of longan to reduce fungal fruit rot caused by the pathogens.
Show more [+] Less [-]Early storage root bulking index and agronomic traits associated with early bulking in cassava Full text
2016
Chipeta, Michael M. | Shanahan, Paul | Melis, Rob | Sibiya, Julia | Benesi, Ibrahim R.M.
One of the attempts by farmers in counteracting the devastating effects of cassava brown streak disease (CBSD) on yield and quality of cassava is early harvesting. However, most varieties grown by farmers are often late bulking which increases the disease severity while on the other hand early harvesting results in significant yield losses. Farmers, therefore, need early storage root bulking cassava varieties in order to reduce the time to harvest leading to a faster rate of return to investment, while at the same time avoiding devastating effects of CBSD on yield and quality of cassava. The study was, therefore, conducted to identify high-yielding and early storage root bulking cassava genotypes as well as traits associated with early storage root bulking and estimate yield loss if any due to early harvesting. The overall aim was to generate information that would guide future improvement programmes for high-yielding and early-bulking cassava varieties in Malawi and other countries facing similar challenges. Trials were implemented using a square lattice design with three replications at two locations for two growing seasons with three harvest intervals (6, 9 and 12 months after planting, MAP). High yields were obtained of up to 9.5t/ha at 6 and 17.8t/ha at 9 MAP. Furthermore, the study revealed that yields obtained at 9 MAP were higher than those obtained at 12 MAP for some genotypes which suggests that such genotypes would be considered as early storage root bulking. Simple correlation analysis identified harvest index, storage root number, storage root diameter and storage root length as the selection criteria to achieve high fresh storage root yield (t/ha) and dry mass yield (t/ha). Path coefficient analysis allocated harvest index and shoot mass as the major selection criteria in improving fresh storage yield and dry mass yield. The study suggests that both source and sink capacities were important for determining early yield. Therefore, these two traits are the key determinants of early storage root bulking and should be used when selecting early-bulking cultivars and indirectly selecting for storage root number, storage root diameter and storage root length.
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